Question 1: Which histologic finding is pathognomonic for lichen planus?

• Max-Joseph spaces with saw-tooth rete ridges (Correct answer)
• Spongiform pustules of Kogoj
• Pautrier microabscesses
• Munro microabscesses

Correct answer: Max-Joseph spaces with saw-tooth rete ridges

Lichen planus shows vacuolar interface dermatitis with Max-Joseph spaces, saw-tooth rete ridges, and a band-like lymphocytic infiltrate.

Question 2: A patient presents with discrete, flat-topped, polygonal, violaceous papules on the wrists. What is the most likely diagnosis?

• Secondary syphilis
• Pityriasis rosea
• Psoriasis
• Lichen planus (Correct answer)

Correct answer: Lichen planus

Lichen planus classically presents with the '6 P's': pruritic, planar, polygonal, purple papules and plaques.

Question 3: The 'saw-tooth' pattern of rete ridges on skin histology is most characteristic of which condition?

• Seborrheic dermatitis
• Systemic lupus erythematosus
• Lichen planus (Correct answer)
• Psoriasis

Correct answer: Lichen planus

Lichen planus shows irregular, saw-tooth shaped rete ridges with a band-like lymphocytic infiltrate hugging the dermal-epidermal junction.

Question 4: Which laser type is considered the gold standard for treating port-wine stains?

• Fractional CO2 laser
• Q-switched Nd:YAG laser
• Alexandrite laser
• Pulsed dye laser (585/595 nm) (Correct answer)

Correct answer: Pulsed dye laser (585/595 nm)

The pulsed dye laser, which targets oxyhemoglobin at 585 or 595 nm, is the treatment of choice for port-wine stains and other vascular lesions using the principle of selective photothermolysis.

Question 5: The Fitzpatrick scale, developed in 1975, classifies human skin into how many phototypes?

• Eight
• Ten
• Six (Correct answer)
• Four

Correct answer: Six

Thomas Fitzpatrick developed a six-type scale (I–VI) to classify skin response to UV radiation based on pigmentation and burn/tan tendency.

Question 6: What is excessive scaling?

• Seborrhea (Correct answer)
• Epidermal Collarette
• Dandruff
• Gross

Correct answer: Seborrhea

Seborrhea is a common skin condition characterized by excessive scaling, flaking, and sometimes greasiness of the skin. It results from an overproduction of sebum and/or abnormal keratinization, leading to visible flakes often referred to as dandruff.

Question 7: Which skin-associated lymphoma is the most common primary cutaneous T-cell lymphoma and presents with patches, plaques, and tumors?

• Primary cutaneous anaplastic large cell lymphoma
• Mycosis fungoides (Correct answer)
• Subcutaneous panniculitis-like T-cell lymphoma
• Sézary syndrome

Correct answer: Mycosis fungoides

Mycosis fungoides is the most common primary cutaneous T-cell lymphoma, progressing from eczematous patches to plaques to tumors.

Question 8: Gianotti-Crosti syndrome (papular acrodermatitis of childhood) is most commonly associated with which viral infection?

• Hepatitis B virus
• Parvovirus B19
• Epstein-Barr virus (EBV) (Correct answer)
• Cytomegalovirus

Correct answer: Epstein-Barr virus (EBV)

While historically associated with hepatitis B, Gianotti-Crosti syndrome in the US is now most commonly triggered by EBV infection, presenting with papular eruption on the face and extremities.

Question 9: Dapsone is used in dermatology primarily for which two conditions?

• Vitiligo and alopecia areata
• Psoriasis and eczema
• Acne and rosacea
• Dermatitis herpetiformis and leprosy (Correct answer)

Correct answer: Dermatitis herpetiformis and leprosy

Dapsone is the drug of choice for dermatitis herpetiformis and is a key component of multidrug therapy for leprosy, working through anti-inflammatory and antimicrobial mechanisms.

Question 10: Which of the following is the first-line treatment for onychomycosis caused by dermatophytes?

• Topical ciclopirox
• Oral terbinafine (Correct answer)
• Oral fluconazole
• Topical clotrimazole

Correct answer: Oral terbinafine

Oral terbinafine is the first-line treatment for dermatophyte onychomycosis due to its high cure rates and fungicidal activity.

Question 11: Which histological feature best characterizes Kaposi sarcoma and distinguishes it from other vascular tumors?

• Epithelioid endothelial cells with hobnail morphology
• Slit-like vascular spaces with spindle cells and extravasated erythrocytes (Correct answer)
• Cavernous dilated vascular channels lined by flat endothelium
• Glomeruloid vascular structures within dermal nodules

Correct answer: Slit-like vascular spaces with spindle cells and extravasated erythrocytes

Kaposi sarcoma shows slit-like irregular vascular spaces lined by spindle cells with extravasated red blood cells and hemosiderin deposition, reflecting its HHV-8-driven spindle cell proliferation.

Question 12: What is the first-line treatment for onychomycosis confirmed by positive fungal culture?

• Oral fluconazole
• Oral terbinafine (Correct answer)
• Topical ciclopirox
• Topical clotrimazole

Correct answer: Oral terbinafine

Oral terbinafine for 12 weeks is first-line for toenail onychomycosis due to its high cure rate and fungicidal mechanism against dermatophytes.

Question 13: Which of the three skin layers contains the most fat and is therefore the thickest?

• subcutaneous tissue (Correct answer)
• epidermis
• dermis
• epithelium

Correct answer: subcutaneous tissue

The subcutaneous tissue, also known as the hypodermis, is the deepest layer of the skin. It is primarily composed of adipose (fat) tissue and loose connective tissue. This layer serves as an insulator, shock absorber, and energy reserve, making it typically the thickest layer of the skin.

Question 14: A 45-year-old presents with a scaly, erythematous plaque with silver scale on the extensor surface of the elbow. The Auspitz sign is positive. What is the most likely diagnosis?

• Seborrheic dermatitis
• Pityriasis rosea
• Lichen planus
• Psoriasis vulgaris (Correct answer)

Correct answer: Psoriasis vulgaris

Auspitz sign (pinpoint bleeding when scale is removed) is characteristic of psoriasis vulgaris, commonly found on extensor surfaces.

Question 15: What is the ABCDE rule used to evaluate in dermatology?

• Age, Biopsy, Curettage, Dermoscopy, Excision
• Appearance, Bleeding, Crust, Diameter, Erythema
• Asymmetry, Border irregularity, Color variation, Diameter >6mm, Evolution (Correct answer)
• Atopy, Barrier dysfunction, Contact allergy, Dryness, Erythema

Correct answer: Asymmetry, Border irregularity, Color variation, Diameter >6mm, Evolution

The ABCDE criteria — Asymmetry, Border irregularity, Color variation, Diameter greater than 6mm, and Evolution — are used to assess pigmented lesions for potential melanoma.

Question 16: What is the mechanism of action of cryotherapy in treating actinic keratoses?

• Thermal denatura­tion of keratin proteins
• Chemical destruction of the stratum corneum
• Selective thermolysis of pigmented cells
• Rapid freezing causes intracellular ice crystal formation and cell destruction (Correct answer)

Correct answer: Rapid freezing causes intracellular ice crystal formation and cell destruction

Cryotherapy destroys abnormal cells through rapid freezing with liquid nitrogen, causing intracellular ice crystal formation, membrane disruption, and subsequent cell death.

Question 17: Which injection technique minimizes the risk of intravascular filler injection in the glabellar region?

• Perpendicular needle insertion to periosteum
• Deep subcutaneous injection with large bolus technique
• Rapid high-pressure injection
• Aspiration before injection, small aliquots, low injection pressure, and superficial dermal placement (Correct answer)

Correct answer: Aspiration before injection, small aliquots, low injection pressure, and superficial dermal placement

In the high-risk glabellar region, aspiration, small aliquot injection, low pressure, superficial placement, and knowledge of vascular anatomy help prevent catastrophic intravascular injection.

Question 18: Which anatomic structure marks the junction between the epidermis and dermis and plays a key role in anchoring the two layers?

• Stratum granulosum
• Papillary dermis capillaries
• Basement membrane zone (Correct answer)
• Rete pegs only

Correct answer: Basement membrane zone

The basement membrane zone (dermal-epidermal junction) contains hemidesmosomes, laminin, and type IV collagen that anchor the epidermis to the dermis.

Question 19: Infantile hemangiomas reach their peak size at approximately what age?

• Birth
• 3–5 months of age (Correct answer)
• 2–3 years of age
• 12–18 months of age

Correct answer: 3–5 months of age

Infantile hemangiomas are absent or barely visible at birth, proliferate rapidly in the first 3–5 months of life reaching peak size, then slowly involute over years.

Question 20: Which direct immunofluorescence pattern is characteristic of pemphigus vulgaris?

• Granular IgA deposits in dermal papillae
• Linear IgG and C3 at the basement membrane zone
• Granular IgM at the dermal-epidermal junction
• Intercellular IgG in a 'chicken wire' pattern (Correct answer)

Correct answer: Intercellular IgG in a 'chicken wire' pattern

Pemphigus vulgaris shows intercellular IgG deposits creating a 'chicken wire' or 'fish net' pattern throughout the epidermis due to anti-desmoglein autoantibodies.

Question 21: Both clotrimazole and nystatin are?

• topical antifungals (Correct answer)
• used to treat eczema
• topical antibiotics
• anti-itch creams

Correct answer: topical antifungals

Clotrimazole and nystatin are both well-known medications used to treat fungal infections. They are commonly available as topical creams, ointments, or powders and work by inhibiting the growth of fungi on the skin or mucous membranes. They are effective against a wide range of fungal pathogens.

Question 22: Which skin condition, historically called 'the great imitator,' can mimic virtually any dermatological disease in its secondary stage?

• Drug hypersensitivity syndrome
• Secondary syphilis (Correct answer)
• Pityriasis rosea
• Systemic lupus erythematosus

Correct answer: Secondary syphilis

Secondary syphilis produces a wide variety of skin manifestations—maculopapular rashes, condylomata lata, alopecia—earning syphilis the nickname 'the great imitator.'

Question 23: Which laser is specifically used for tattoo removal based on the principle of selective photothermolysis?

• CO2 fractional laser
• Diode laser
• Pulsed dye laser
• Q-switched Nd:YAG, alexandrite, or ruby laser (Correct answer)

Correct answer: Q-switched Nd:YAG, alexandrite, or ruby laser

Q-switched lasers (Nd:YAG 1064/532 nm, alexandrite 755 nm, ruby 694 nm) deliver nanosecond pulses that fragment tattoo ink particles into smaller pieces cleared by macrophages.

Question 24: Which biologic drug class is approved for moderate-to-severe plaque psoriasis and works by inhibiting IL-17A?

• TNF-alpha inhibitors
• IL-17A inhibitors (Correct answer)
• IL-12/23 inhibitors
• IL-23 inhibitors

Correct answer: IL-17A inhibitors

Secukinumab and ixekizumab are IL-17A inhibitors approved for moderate-to-severe plaque psoriasis with high efficacy.

Question 25: What can be the Remnants of a pustule, vesicle, or bulla?

• Cyst
• Plaque
• Scale
• Epidermal Collarette (Correct answer)

Correct answer: Epidermal Collarette

An epidermal collarette is a circular rim of scale that represents the remnants of the roof of a ruptured pustule, vesicle, or bulla. It indicates a previous lesion that has healed or is in the process of healing, often seen in pyoderma.

Question 26: What is the most common benign skin tumor in adults?

• Lipoma
• Epidermal inclusion cyst
• Seborrheic keratosis (Correct answer)
• Dermatofibroma

Correct answer: Seborrheic keratosis

Seborrheic keratosis is the most common benign epidermal tumor in adults, increasing in number and size with age and typically requiring no treatment.

Question 27: 'Naked granulomas' (non-caseating granulomas with sparse surrounding lymphocytes) in skin biopsies are characteristic of which systemic condition?

• Sarcoidosis (Correct answer)
• Rheumatoid nodule
• Granuloma annulare
• Crohn's disease with cutaneous involvement

Correct answer: Sarcoidosis

Sarcoidosis produces 'naked' non-caseating epithelioid granulomas with minimal surrounding lymphocytic infiltrate, often with Langhans giant cells and inclusion bodies.

Question 28: Which of the following conditions is caused by a fungus?

• tinea capitis (Correct answer)
• suborrhea
• lichen planus
• keratosis

Correct answer: tinea capitis

Tinea capitis is a fungal infection that specifically affects the scalp and hair shafts, commonly known as ringworm of the scalp. It is caused by dermatophytes, a type of fungus that feeds on keratin. The other options listed are not primarily caused by fungal pathogens.

Question 29: The phrase 'herald patch' is the classic initial presentation of which common self-limited skin eruption?

• Tinea corporis
• Secondary syphilis
• Guttate psoriasis
• Pityriasis rosea (Correct answer)

Correct answer: Pityriasis rosea

Pityriasis rosea classically begins with a single large 'herald patch' followed days to weeks later by a widespread Christmas-tree pattern eruption.

Question 30: Parakeratosis is defined as which histological finding?

• Retention of nuclei within the stratum corneum (Correct answer)
• Increased thickness of the stratum spinosum
• Neutrophil infiltration within the epidermis
• Absence of the stratum granulosum

Correct answer: Retention of nuclei within the stratum corneum

Parakeratosis is the retention of nuclei in the stratum corneum, indicating abnormal keratinization and rapid epidermal turnover, as seen in psoriasis.

Question 31: Which congenital melanocytic nevus size poses the greatest risk of malignant melanoma transformation?

• Medium CMN (1.5–19.9 cm)
• Speckled lentiginous nevus
• Small CMN (<1.5 cm)
• Giant CMN (>20 cm in adult equivalent size) (Correct answer)

Correct answer: Giant CMN (>20 cm in adult equivalent size)

Giant congenital melanocytic nevi (>20 cm) carry the highest lifetime risk of melanoma transformation (estimated 5–10%) and are also associated with neurocutaneous melanocytosis.

Question 32: A 55-year-old construction worker has a 2 cm hyperkeratotic, ulcerated lesion on the lower lip with regional lymphadenopathy. What is the most likely diagnosis?

• Squamous cell carcinoma (Correct answer)
• Keratoacanthoma
• Actinic cheilitis
• Herpes labialis

Correct answer: Squamous cell carcinoma

Squamous cell carcinoma of the lip is common in sun-exposed, fair-skinned individuals and can metastasize to regional nodes.

Question 33: What histological finding is characteristic of mycosis fungoides (cutaneous T-cell lymphoma)?

• Granulomas with central caseation
• Acanthosis with parakeratosis
• Pautrier microabscesses with atypical lymphocytes in the epidermis (Correct answer)
• Subepidermal clefting with eosinophils

Correct answer: Pautrier microabscesses with atypical lymphocytes in the epidermis

Pautrier microabscesses — collections of atypical cerebriform T-lymphocytes within the epidermis — are pathognomonic of mycosis fungoides on histology.

Question 34: A teenager presents with grouped erythematous papules and nodules along the jawline and perioral area. Which hormonal influence is most implicated?

• Estrogen dominance
• Elevated cortisol from stress
• Growth hormone
• Androgens stimulating sebaceous gland activity and sebum production (Correct answer)

Correct answer: Androgens stimulating sebaceous gland activity and sebum production

Teenage acne along the jawline and lower face is driven by androgen-stimulated sebaceous gland hypertrophy and increased sebum production, particularly during puberty.

Question 35: What histological hallmark differentiates Bowen disease (SCC in situ) from invasive SCC?

• Keratin pearl formation
• Perineural invasion
• Full-thickness epidermal dysplasia without invasion through the basement membrane (Correct answer)
• Lymphovascular invasion

Correct answer: Full-thickness epidermal dysplasia without invasion through the basement membrane

Bowen disease shows full-thickness dysplasia of the epidermis with preserved basement membrane — by definition, carcinoma in situ has not breached the basement membrane to invade the dermis.

Question 36: What is the recommended first-line systemic treatment for severe atopic dermatitis in adults when topical therapy fails?

• Dupilumab (IL-4Rα biologic) (Correct answer)
• Methotrexate
• Oral prednisone
• Systemic cyclosporine

Correct answer: Dupilumab (IL-4Rα biologic)

Dupilumab is now the preferred first-line systemic agent for moderate-to-severe atopic dermatitis in adults, offering superior efficacy and safety compared to traditional immunosuppressants.

Question 37: 'Interface dermatitis' describes inflammatory damage primarily at which anatomical site?

• At the dermal-epidermal junction (Correct answer)
• Between the dermis and subcutaneous fat
• Within the mid-dermis
• Between the dermis and follicular epithelium

Correct answer: At the dermal-epidermal junction

Interface dermatitis refers to a lichenoid inflammatory pattern at the dermal-epidermal junction, causing vacuolar change or band-like infiltrate, as seen in lichen planus and lupus.

Question 38: The skin's vascular layer is called the?

• dermis (Correct answer)
• epidermis
• stratum corneum unguis
• hypodermis

Correct answer: dermis

The dermis is the middle layer of the skin, located beneath the epidermis. It is rich in blood vessels, nerves, hair follicles, and sweat glands, making it the primary vascular layer responsible for nourishing the skin and providing its structural integrity.

Question 39: Which topical therapy is first-line treatment for molluscum contagiosum in immunocompetent children?

• Watchful waiting or cantharidin application (Correct answer)
• Imiquimod 5% cream
• Cidofovir cream
• Podophyllotoxin

Correct answer: Watchful waiting or cantharidin application

Molluscum contagiosum in immunocompetent children typically self-resolves; if treatment is desired, cantharidin (blister beetle extract) or watchful waiting are preferred approaches.

Question 40: Nikolsky's sign is positive in which of the following conditions?

• Dermatitis herpetiformis
• Bullous pemphigoid
• Pemphigus vulgaris (Correct answer)
• Epidermolysis bullosa acquisita

Correct answer: Pemphigus vulgaris

Nikolsky's sign — lateral pressure causing epidermal slippage — is positive in pemphigus vulgaris due to loss of keratinocyte cohesion from anti-desmoglein antibodies.

Question 41: A 30-year-old woman presents with periorbital heliotrope rash and Gottron's papules over the knuckles. What is the most likely diagnosis?

• Mixed connective tissue disease
• Systemic lupus erythematosus
• Dermatomyositis (Correct answer)
• Psoriatic arthritis

Correct answer: Dermatomyositis

Heliotrope rash and Gottron's papules are pathognomonic features of dermatomyositis.

Question 42: Which electrosurgical technique uses alternating current to destroy tissue while controlling hemostasis?

• Electrodesiccation and curettage (ED&C) (Correct answer)
• Radiofrequency ablation
• Electrolysis
• Iontophoresis

Correct answer: Electrodesiccation and curettage (ED&C)

Electrodesiccation and curettage uses high-frequency alternating current to dehydrate and destroy superficial tumor tissue, followed by physical removal with a curette.

Question 43: Which systemic medication requires monthly pregnancy tests and two forms of contraception due to severe teratogenicity?

• Isotretinoin (Correct answer)
• Hydroxychloroquine
• Methotrexate
• Dapsone

Correct answer: Isotretinoin

Isotretinoin is highly teratogenic, causing severe fetal malformations, and requires enrollment in the iPLEDGE program with mandatory monthly pregnancy testing and dual contraception.

Question 44: What is the vehicle that determines the potency classification of topical corticosteroids?

• The formulation (ointment > gel > cream > lotion > solution) significantly affects potency (Correct answer)
• Molecular weight of the steroid
• Concentration alone determines potency
• pH of the preparation

Correct answer: The formulation (ointment > gel > cream > lotion > solution) significantly affects potency

The same corticosteroid molecule can have different potency classes depending on the vehicle — ointments provide the greatest occlusion and skin penetration, followed by gels, creams, and lotions.

Question 45: Which condition presents with comedones, papules, pustules, and nodules primarily on the face, chest, and back?

• Perioral dermatitis
• Folliculitis
• Rosacea
• Acne vulgaris (Correct answer)

Correct answer: Acne vulgaris

Acne vulgaris involves follicular plugging (comedones) that progress to inflammatory papules, pustules, and nodules on sebaceous gland-rich areas of the face, chest, and back.

Question 46: Which phototherapy modality delivers narrowband ultraviolet B (NB-UVB) radiation at approximately 311–313 nm?

• Broadband UVB
• PUVA (psoralen + UVA)
• Excimer laser
• Narrowband UVB lamp (Correct answer)

Correct answer: Narrowband UVB lamp

Narrowband UVB phototherapy uses a fluorescent lamp that emits UVB radiation at the therapeutic peak of 311–313 nm, which is more effective and safer than broadband UVB.

Question 47: Flame figures in the dermis are classically associated with which dermatological condition?

• Wells syndrome (eosinophilic cellulitis) (Correct answer)
• Dermatitis herpetiformis
• Granuloma annulare
• Erythema nodosum

Correct answer: Wells syndrome (eosinophilic cellulitis)

Flame figures are eosinophilic granular deposits coating collagen fibers, characteristic of Wells syndrome (eosinophilic cellulitis), a recurrent eosinophilic dermatosis.

Question 48: What is the pathognomonic skin finding of Kawasaki disease in children?

• Target lesions on the trunk and extremities
• Vesicular eruption on palms and soles
• Palpable purpura on the lower extremities
• Polymorphous exanthem with desquamation of fingertips in the recovery phase (Correct answer)

Correct answer: Polymorphous exanthem with desquamation of fingertips in the recovery phase

Kawasaki disease features a polymorphous rash plus desquamation of the fingertips and toes beginning in the periungual region during the subacute phase (10–25 days after fever onset).

Question 49: What is the role of niacinamide (nicotinamide) in topical skin care and dermatology?

• Inhibits tyrosinase activity
• Reduces transepidermal water loss, decreases sebum production, and inhibits melanosome transfer (Correct answer)
• Directly bleaches melanin pigment
• Blocks UV-B radiation

Correct answer: Reduces transepidermal water loss, decreases sebum production, and inhibits melanosome transfer

Topical niacinamide improves the skin barrier by increasing ceramide synthesis, reduces TEWL, decreases sebum production, and inhibits melanosome transfer from melanocytes to keratinocytes.

Question 50: Which histological feature best distinguishes superficial spreading melanoma from a benign compound nevus?

• Presence of melanin pigment
• Presence of dermal melanocytes
• Pagetoid spread of melanocytes into upper epidermal layers (Correct answer)
• Nesting of melanocytes at the dermal-epidermal junction

Correct answer: Pagetoid spread of melanocytes into upper epidermal layers

Pagetoid spread refers to single melanocytes or nests ascending into the upper epidermis, a hallmark of melanoma not seen in benign nevi.

Question 51: A patient with HIV presents with diffuse brownish-red macules and papules on the palms and soles. Which diagnosis should be considered first?

• Pityriasis rosea
• Drug eruption
• Secondary syphilis (Correct answer)
• Kaposi's sarcoma

Correct answer: Secondary syphilis

Palm and sole involvement is a hallmark of secondary syphilis, which must be ruled out in any sexually active or immunocompromised patient.

Question 52: Pautrier microabscesses on skin biopsy are characteristic of which condition?

• Atopic dermatitis
• Mycosis fungoides (Correct answer)
• Folliculitis decalvans
• Psoriasis

Correct answer: Mycosis fungoides

Pautrier microabscesses are intraepidermal collections of atypical T lymphocytes (cerebriform nuclei) that are pathognomonic of mycosis fungoides (cutaneous T-cell lymphoma).

Question 53: Which rare genodermatosis causes blistering at the site of minor trauma due to mutations in structural proteins of the epidermis or basement membrane?

• Ichthyosis vulgaris
• Epidermolysis bullosa (Correct answer)
• Darier disease
• Hailey-Hailey disease

Correct answer: Epidermolysis bullosa

Epidermolysis bullosa encompasses a group of inherited disorders caused by mutations in keratin, laminin, or collagen VII genes, resulting in extreme skin fragility.

Question 54: Nikolsky's sign, where lateral pressure causes the skin to slide and blister, is positive in which condition?

• Pemphigus vulgaris (Correct answer)
• Dermatitis herpetiformis
• Bullous pemphigoid
• Epidermolysis bullosa acquisita

Correct answer: Pemphigus vulgaris

Nikolsky's sign is positive in pemphigus vulgaris due to the fragile suprabasal cleavage plane caused by desmoglein 3 autoantibodies.

Question 55: A severe outbreak of extremely itchy papules or wheals is referred to as?

• psoriasis
• urticaria (Correct answer)
• acne vulgaris
• pityriasis rosea

Correct answer: urticaria

Urticaria, commonly known as hives, is characterized by a severe outbreak of extremely itchy, raised, red, or skin-colored welts (wheals) or papules on the skin. These lesions can appear suddenly and often disappear within hours, only to reappear elsewhere. It is typically an allergic reaction or a response to various triggers.

Question 56: A 35-year-old woman has butterfly-shaped facial erythema, photosensitivity, and a positive ANA. Which antibody is most specific for SLE?

• Anti-histone
• Anti-Ro (SSA)
• Anti-La (SSB)
• Anti-dsDNA (Correct answer)

Correct answer: Anti-dsDNA

Anti-dsDNA antibodies are highly specific for SLE and their titers often correlate with disease activity, particularly lupus nephritis.

Question 57: Palisading granulomas with central necrobiosis of collagen and mucin are the histological hallmark of which condition?

• Sarcoidosis
• Granuloma annulare (Correct answer)
• Lepromatous leprosy
• Foreign body granuloma

Correct answer: Granuloma annulare

Granuloma annulare is characterized by palisading histiocytes surrounding central zones of degenerated collagen and mucin deposition in the dermis.

Question 58: What is the approximate total surface area of the skin in an average adult human?

• 3–4 square meters
• 0.5–1 square meter
• 1.5–2 square meters (Correct answer)
• 2.5–3 square meters

Correct answer: 1.5–2 square meters

The adult human skin covers approximately 1.5–2 square meters, making it the body's largest organ.

Question 59: Which ABCDE criterion for melanoma evaluation stands for 'Evolution'?

• The lesion is asymmetric
• The lesion has multiple colors
• The lesion has changed over time (Correct answer)
• The lesion has irregular borders

Correct answer: The lesion has changed over time

The 'E' in ABCDE stands for Evolution — any change in size, shape, color, or a new symptom such as bleeding is a warning sign of melanoma.

Question 60: Which type of non-melanoma skin cancer is most commonly seen in organ transplant recipients on long-term immunosuppression?

• Merkel cell carcinoma
• Basal cell carcinoma
• Sebaceous carcinoma
• Squamous cell carcinoma (SCC) (Correct answer)

Correct answer: Squamous cell carcinoma (SCC)

Immunosuppressed transplant recipients develop SCC at dramatically higher rates (65–250 times higher) than the general population, with SCC outnumbering BCC — the reverse of the normal ratio.

Question 61: Which skin sign—yellowing of the sclerae and skin—most commonly indicates which underlying metabolic process?

• Elevated serum bilirubin from hepatic or hemolytic disease (Correct answer)
• Iron deposition in hemochromatosis
• Lipid deposition in xanthomatosis
• Elevated serum carotenoids from diet

Correct answer: Elevated serum bilirubin from hepatic or hemolytic disease

True jaundice with scleral icterus reflects hyperbilirubinemia (>2–3 mg/dL) from liver disease or hemolysis, not dietary carotenoids.

Question 62: Sentinel lymph node biopsy is recommended for melanomas with Breslow thickness greater than which measurement?

• 0.5 mm
• 0.8 mm (or 0.8–1.0 mm with high-risk features) (Correct answer)
• 1.5 mm
• 2.0 mm

Correct answer: 0.8 mm (or 0.8–1.0 mm with high-risk features)

Current NCCN guidelines recommend sentinel lymph node biopsy for melanomas >0.8 mm in Breslow thickness, or for thinner melanomas with ulceration or high mitotic rate.

Question 63: What is the correct depth of injection for hyaluronic acid filler used to treat nasolabial folds?

• Subperiosteal plane
• Deep dermis to subcutaneous junction (Correct answer)
• Muscle belly
• Superficial epidermis

Correct answer: Deep dermis to subcutaneous junction

Nasolabial fold correction with HA filler requires injection at the deep dermis to subcutaneous junction to provide volume support and lift without visibility of filler.

Question 64: Which gene is most commonly mutated in familial melanoma?

• CDKN2A (Correct answer)
• NRAS
• KIT
• BRAF

Correct answer: CDKN2A

CDKN2A (encoding p16/INK4a) is the most frequently mutated gene in hereditary melanoma-prone families.

Question 65: Which layer of the epidermis is responsible for cell division and renewal?

• Stratum corneum
• Stratum basale (Correct answer)
• Stratum granulosum
• Stratum spinosum

Correct answer: Stratum basale

The stratum basale contains mitotically active keratinocytes that continuously divide to renew the epidermis.

Question 66: Which skin neoplasm is linked to an increase in cell development in the epidermis' keratin layer brought on by pressure or friction?

• keratosis
• callus (Correct answer)
• leukoplakia
• keloid

Correct answer: callus

A callus is a thickened area of skin that develops in response to repeated pressure or friction. It is a protective mechanism where the epidermis, specifically the keratin layer, increases cell production to create a tougher, more resilient surface. Calluses are benign and are commonly found on the hands and feet.

Question 67: The Koebner phenomenon refers to the appearance of skin lesions at sites of:

• Trauma or injury (Correct answer)
• Sun exposure
• Bacterial infection
• Allergic reaction

Correct answer: Trauma or injury

The Koebner (isomorphic) phenomenon occurs when skin disease appears at sites of trauma, classically seen in psoriasis, vitiligo, and lichen planus.

Question 68: Which mite is responsible for scabies infestation in humans?

• Demodex folliculorum
• Cheyletiella yasguri
• Dermatophagoides pteronyssinus
• Sarcoptes scabiei var. hominis (Correct answer)

Correct answer: Sarcoptes scabiei var. hominis

Scabies is caused by the burrowing mite Sarcoptes scabiei var. hominis, which is transmitted through close physical contact.

Question 69: Which topical medication is first-line for treating cradle cap (infantile seborrheic dermatitis) on the scalp?

• Gentle emollient oils and mild antifungal shampoos (Correct answer)
• Salicylic acid peels
• Coal tar preparations
• High-potency topical corticosteroids

Correct answer: Gentle emollient oils and mild antifungal shampoos

Cradle cap is managed with gentle emollient oils to loosen scales followed by mild ketoconazole or antifungal shampoos, reserving low-potency steroids for resistant cases.

Question 70: Which filler material provides the longest duration of effect among commonly used dermal fillers?

• Hyaluronic acid fillers
• Poly-L-lactic acid (Sculptra) (Correct answer)
• Calcium hydroxylapatite (Radiesse)
• Collagen fillers

Correct answer: Poly-L-lactic acid (Sculptra)

Poly-L-lactic acid (Sculptra) is a biostimulatory filler that stimulates neocollagenesis over months, with results lasting up to 2 years or more.

Question 71: A patient presents with diffuse hair shedding 3 months after a major surgery. What type of alopecia is this?

• Anagen effluvium
• Alopecia areata
• Androgenetic alopecia
• Telogen effluvium (Correct answer)

Correct answer: Telogen effluvium

Telogen effluvium occurs 2–4 months after a physiological stressor (surgery, illness, childbirth), causing premature shift of hair follicles into the telogen phase.

Question 72: What does yellowing of the skin indicate?

• hyperkalemia
• hyperbilirubinemia (Correct answer)
• hyporeninemia
• hyperuricemia

Correct answer: hyperbilirubinemia

Yellowing of the skin, known as jaundice, is a clinical sign of hyperbilirubinemia, which is an excess of bilirubin in the blood. Bilirubin is a yellow pigment produced during the breakdown of red blood cells. Elevated levels can indicate liver disease, bile duct obstruction, or excessive red blood cell destruction.

Question 73: Extramammary Paget disease most commonly affects which anatomical sites?

• Face and scalp
• Trunk and extremities
• Vulva, perianal region, and scrotum (Correct answer)
• Axillae and neck

Correct answer: Vulva, perianal region, and scrotum

Extramammary Paget disease presents as erythematous, eczematous plaques with large clear (Paget) cells and may be associated with an underlying adnexal or visceral adenocarcinoma.

Question 74: Death of tissue resulting from a reduction in blood flow to the affected area is referred to as?

• psoriasis
• cellulitis
• eczema
• gangrene (Correct answer)

Correct answer: gangrene

Gangrene is a serious and potentially life-threatening condition that occurs when a significant amount of body tissue dies. This tissue death results from a severe lack of blood supply to the affected area, often caused by injury, infection, or underlying conditions that impair circulation. The reduced blood flow deprives the tissue of essential oxygen and nutrients, leading to its necrosis.

Question 75: Koebner phenomenon — appearance of lesions along lines of trauma — is classically seen in which condition?

• Psoriasis (Correct answer)
• Atopic dermatitis
• Acne vulgaris
• Seborrheic dermatitis

Correct answer: Psoriasis

The Koebner (isomorphic) phenomenon, where new psoriatic plaques develop at sites of skin trauma or injury, is a hallmark feature of psoriasis.

Question 76: What is the name of a chronic dermatitis in people with a history of allergies that has no recognized cause?

• atopic dermatitis (Correct answer)
• actinic dermatitis
• stasis dermatitis
• seborrheic dermatitis

Correct answer: atopic dermatitis

Atopic dermatitis, also known as eczema, is a chronic inflammatory skin condition characterized by dry, intensely itchy, and inflamed skin. It often begins in childhood and is strongly associated with a personal or family history of allergies, asthma, or hay fever, forming part of the 'atopic triad.' While its exact cause is unknown, it involves a complex interplay of genetic, environmental, and immunological factors.

Question 77: IL-17A inhibitors (secukinumab, ixekizumab) are approved for which dermatological condition?

• Atopic dermatitis
• Alopecia areata
• Moderate-to-severe plaque psoriasis (Correct answer)
• Hidradenitis suppurativa

Correct answer: Moderate-to-severe plaque psoriasis

Secukinumab and ixekizumab target IL-17A, a key downstream cytokine in the IL-23/Th17 axis, and are FDA-approved for moderate-to-severe plaque psoriasis with excellent efficacy.

Question 78: Which feature best distinguishes seborrheic keratosis from a melanoma?

• Rapid growth over weeks
• Pruritus and bleeding
• Asymmetric borders and color variation
• Stuck-on appearance with horn cysts visible on dermoscopy (Correct answer)

Correct answer: Stuck-on appearance with horn cysts visible on dermoscopy

Seborrheic keratosis has a characteristic 'stuck-on' waxy appearance with comedone-like openings (horn cysts) seen on dermoscopy, distinguishing it from melanoma.

Question 79: Which dermatoscopic structure is most associated with melanoma?

• Arborizing vessels
• Atypical pigment network (Correct answer)
• Comma vessels
• Milia-like cysts

Correct answer: Atypical pigment network

An atypical (irregular) pigment network with variable thickness and abrupt termination at the periphery is a key dermoscopic feature of melanoma.

Question 80: Dupilumab (Dupixent) works by blocking the receptor for which cytokines in atopic dermatitis?

• IL-4 and IL-13 (Correct answer)
• TNF-alpha and IL-1
• IL-12 and IL-23
• IL-17A and IL-17F

Correct answer: IL-4 and IL-13

Dupilumab is a monoclonal antibody that blocks the IL-4Rα subunit shared by IL-4 and IL-13 receptors, inhibiting the Th2 inflammatory cascade central to atopic dermatitis.

Question 81: Which type of hypersensitivity reaction underlies allergic contact dermatitis?

• Type II (cytotoxic)
• Type III (immune complex)
• Type IV (delayed-type) (Correct answer)
• Type I (IgE-mediated)

Correct answer: Type IV (delayed-type)

Allergic contact dermatitis is a Type IV (cell-mediated, delayed-type) hypersensitivity reaction involving sensitized T lymphocytes.

Question 82: What makes ARF different from FAD?

• Scratching of muzzle
• Papules
• GI Signs (Correct answer)
• Excoriations

Correct answer: GI Signs

ARF (Atopic-like Reaction to Food) is a food allergy, and unlike FAD (Flea Allergy Dermatitis) which primarily causes skin irritation, ARF often presents with gastrointestinal (GI) signs such as vomiting, diarrhea, or changes in appetite, in addition to dermatological symptoms.

Question 83: What is the mechanism of action of terbinafine (Lamisil) in treating onychomycosis?

• Inhibits squalene epoxidase, blocking ergosterol synthesis and causing toxic squalene accumulation (Correct answer)
• Inhibits lanosterol 14α-demethylase
• Disrupts the cell wall beta-glucan synthesis
• Binds to fungal tubulin inhibiting mitosis

Correct answer: Inhibits squalene epoxidase, blocking ergosterol synthesis and causing toxic squalene accumulation

Terbinafine inhibits squalene epoxidase, an earlier step in ergosterol synthesis, causing dual toxicity — ergosterol depletion and accumulation of toxic squalene within the fungal cell.

Question 84: Which dermatological condition famously affected the 16th-century monarch King Henry VIII later in life, contributing to his characteristic appearance?

• Pemphigus vulgaris
• Rosacea flushing
• Syphilitic gummas and leg ulcers (Correct answer)
• Psoriatic plaques

Correct answer: Syphilitic gummas and leg ulcers

Henry VIII likely suffered from syphilitic gummas and chronic leg ulcers, consistent with historical accounts of painful, draining wounds.

Question 85: Squamous cell carcinoma arising in a chronic wound or scar is known as which eponymous carcinoma?

• Bowen disease
• Marjolin ulcer (Correct answer)
• Paget disease
• Spiegler tumor

Correct answer: Marjolin ulcer

Marjolin ulcer is SCC arising from chronic wounds, burn scars, osteomyelitis sinuses, or other areas of chronic inflammation, typically with an aggressive course and higher metastatic risk.

Question 86: What skin findings are associated with celiac disease beyond dermatitis herpetiformis?

• Aphthous ulcers, angular cheilitis, and alopecia (Correct answer)
• Psoriasis and vitiligo
• Acanthosis nigricans and ichthyosis
• Erythema nodosum and pyoderma gangrenosum

Correct answer: Aphthous ulcers, angular cheilitis, and alopecia

Celiac disease is associated with multiple cutaneous manifestations including recurrent aphthous ulcers, angular cheilitis from nutritional deficiencies, and alopecia.

Question 87: Which actinic keratosis feature suggests highest risk of progression to invasive SCC?

• Hypertrophic/thick AK with induration and tenderness (Correct answer)
• Flat pigmented AK
• AK on the forearm
• Multiple thin AKs on the scalp

Correct answer: Hypertrophic/thick AK with induration and tenderness

Hypertrophic, indurated, or tender actinic keratoses have the highest risk of harboring or progressing to invasive SCC and warrant aggressive treatment or biopsy.

Question 88: What dermatological tool, invented in the 1990s, allows in vivo visualization of the epidermis and dermal-epidermal junction without biopsy?

• Confocal reflectance microscopy
• High-frequency ultrasound
• Optical coherence tomography
• Dermoscopy (dermatoscopy) (Correct answer)

Correct answer: Dermoscopy (dermatoscopy)

Dermoscopy uses polarized or contact oil lens illumination to visualize subsurface skin structures, improving melanoma detection accuracy.

Question 89: Which histological subtype of basal cell carcinoma carries the highest risk of recurrence and invasion?

• Pigmented BCC
• Superficial BCC
• Nodular BCC
• Morpheaform (sclerosing/infiltrative) BCC (Correct answer)

Correct answer: Morpheaform (sclerosing/infiltrative) BCC

Morpheaform BCC has indistinct clinical borders with finger-like projections extending well beyond the visible lesion, making it the most aggressive subtype with the highest recurrence rate.

Question 90: Which pigment gives sebaceous gland secretions their characteristic color and contributes to the yellow tint in aged skin?

• Bilirubin
• Carotenoids (Correct answer)
• Lipofuscin
• Melanin

Correct answer: Carotenoids

Dietary carotenoids accumulate in sebaceous secretions and subcutaneous fat, contributing to the yellowish tint seen in the skin.

Question 91: Which immunoglobulin is primarily found at the dermal-epidermal junction in bullous pemphigoid?

• IgA
• IgG (Correct answer)
• IgE
• IgM

Correct answer: IgG

Bullous pemphigoid is characterized by IgG autoantibodies targeting BP180 and BP230 antigens at the dermal-epidermal junction.

Question 92: Mohs micrographic surgery is most appropriate for which type of skin cancer?

• Sebaceous carcinoma on the eyelid
• High-risk basal cell carcinoma on the face with poorly defined borders (Correct answer)
• Thin superficial spreading melanoma on the trunk
• Dermatofibrosarcoma protuberans on the scalp

Correct answer: High-risk basal cell carcinoma on the face with poorly defined borders

Mohs surgery is the gold standard for high-risk BCCs, particularly on the face (H-zone), with recurrent tumors, or poorly defined borders where tissue conservation is critical.

Question 93: What stage of growth is a hair follicle in?

• Growagen
• Catagen
• Anagen (Correct answer)
• Telogen

Correct answer: Anagen

The anagen phase is the active growth phase of hair follicles, where hair cells rapidly divide and new hair is formed. This is the longest stage of the hair cycle, determining the length of the hair.

Question 94: Merkel cell carcinoma is a neuroendocrine tumor associated with which viral pathogen?

• Human herpesvirus 8 (HHV-8)
• Epstein-Barr virus (EBV)
• Human papillomavirus (HPV)
• Merkel cell polyomavirus (MCPyV) (Correct answer)

Correct answer: Merkel cell polyomavirus (MCPyV)

Merkel cell polyomavirus DNA is integrated in approximately 80% of Merkel cell carcinomas, and viral oncoproteins (T antigens) contribute to tumorigenesis by inactivating tumor suppressors.

Question 95: Which SPF value indicates protection against approximately 97% of UVB radiation?

• SPF 100
• SPF 30 (Correct answer)
• SPF 15
• SPF 50

Correct answer: SPF 30

SPF 30 blocks approximately 97% of UVB rays, SPF 50 blocks ~98%, and SPF 100 blocks ~99% — the incremental difference above SPF 30 is minimal.

Question 96: What is the primary mechanism of action of botulinum toxin A in cosmetic dermatology?

• Stimulates collagen production in the dermis
• Blocks substance P to reduce inflammation
• Inhibits acetylcholine release at the neuromuscular junction causing temporary muscle paralysis (Correct answer)
• Disrupts disulfide bonds in keratin filaments

Correct answer: Inhibits acetylcholine release at the neuromuscular junction causing temporary muscle paralysis

Botulinum toxin A cleaves SNAP-25, preventing acetylcholine vesicle fusion at the neuromuscular junction, thereby causing temporary flaccid paralysis of injected muscles.

Question 97: Dermatitis herpetiformis is strongly associated with which systemic condition?

• Inflammatory bowel disease
• Crohn disease
• Systemic lupus erythematosus
• Celiac disease (gluten-sensitive enteropathy) (Correct answer)

Correct answer: Celiac disease (gluten-sensitive enteropathy)

Dermatitis herpetiformis is the cutaneous manifestation of celiac disease, with IgA deposits in dermal papillae triggered by gluten sensitivity.

Question 98: A patient with HIV develops painful, grouped vesicles along a unilateral thoracic dermatome. What is the treatment of choice?

• Intravenous amphotericin B
• Oral doxycycline
• Oral valacyclovir (Correct answer)
• Topical acyclovir

Correct answer: Oral valacyclovir

Herpes zoster in immunocompromised patients is treated with oral valacyclovir or famciclovir; IV acyclovir is reserved for severe or disseminated disease.

Question 99: Which of the following is a high-risk feature of SCC that significantly increases metastatic potential?

• Presence on trunk
• Age <50 at diagnosis
• Tumor diameter >2 cm, depth >2 mm, perineural invasion, or immunosuppression (Correct answer)
• Lesion arising de novo rather than from actinic keratosis

Correct answer: Tumor diameter >2 cm, depth >2 mm, perineural invasion, or immunosuppression

High-risk SCC features include large size (>2 cm), deep invasion (>2 mm), poor differentiation, perineural or lymphovascular invasion, location on ear/lip, and patient immunosuppression.

Question 100: The typical symptoms of this dermatologic condition include erythema, papules, and pustules, as well as follicular dilatation that affects the nose and parts of the cheeks.

• acne pustulosa
• acne rosacea (Correct answer)
• acne vulgaris
• acne cosmetica

Correct answer: acne rosacea

Acne rosacea, commonly known as rosacea, is a chronic inflammatory skin condition primarily affecting the face. Its characteristic symptoms include persistent facial redness (erythema), small red bumps (papules), pus-filled lesions (pustules), and visible blood vessels, often with follicular dilatation, particularly on the nose and cheeks. Unlike acne vulgaris, it typically lacks comedones (blackheads/whiteheads) and is more common in adults.

Question 101: Which topical retinoid is considered the gold standard for treating photodamage and acne?

• Tretinoin (all-trans retinoic acid) (Correct answer)
• Adapalene
• Tazarotene
• Retinol

Correct answer: Tretinoin (all-trans retinoic acid)

Tretinoin is the prototypical topical retinoid with the strongest evidence base for treating acne, photodamage, and fine wrinkles by modulating keratinocyte differentiation and stimulating collagen.

Question 102: Which neurocutaneous syndrome is characterized by café-au-lait macules, axillary freckling, and neurofibromas?

• Neurofibromatosis type 1 (NF1) (Correct answer)
• Sturge-Weber syndrome
• Tuberous sclerosis complex
• Incontinentia pigmenti

Correct answer: Neurofibromatosis type 1 (NF1)

NF1 (von Recklinghausen disease) is diagnosed by ≥6 café-au-lait macules, Lisch nodules, axillary/inguinal freckling, neurofibromas, and other features from autosomal dominant NF1 mutations.

Question 103: A patient presents with grouped vesicles on an erythematous base along a unilateral thoracic dermatome. Which antiviral is first-line?

• Ganciclovir 5 mg/kg IV
• Acyclovir 200 mg 5x/day
• Famciclovir 500 mg BID
• Valacyclovir 1000 mg TID (Correct answer)

Correct answer: Valacyclovir 1000 mg TID

Valacyclovir 1000 mg three times daily for 7 days is preferred for herpes zoster due to improved bioavailability over acyclovir.

Question 104: Which of the following conditions also goes by the name "ringworm"?

• tinea corporis (Correct answer)
• herpes simplex
• folliculitis
• impetigo

Correct answer: tinea corporis

Tinea corporis is the medical term for ringworm of the body. It is a common fungal infection that causes a red, itchy, circular rash with raised edges, often resembling a ring. Despite its name, ringworm is not caused by a worm but by dermatophyte fungi that thrive on keratinized tissues.

Question 105: Which vitamin deficiency causes pellagra, characterized by dermatitis, diarrhea, and dementia?

• Vitamin B1 (thiamine)
• Vitamin C (ascorbic acid)
• Vitamin B3 (niacin) (Correct answer)
• Vitamin B12 (cobalamin)

Correct answer: Vitamin B3 (niacin)

Pellagra results from niacin (vitamin B3) deficiency and classically presents with the '3 Ds': dermatitis, diarrhea, and dementia.

Question 106: What is the name of the embryological process by which melanocytes migrate from the neural crest to the epidermis?

• Epidermal stratification
• Neural crest cell migration (Correct answer)
• Gastrulation
• Dermal condensation

Correct answer: Neural crest cell migration

Melanocytes originate from neural crest cells that migrate during embryogenesis into the epidermis, dermis, and other tissues.

Question 107: Which of the following is a characteristic feature of rosacea that distinguishes it from acne vulgaris?

• Open comedones
• Cystic nodules
• Phymatous skin changes (Correct answer)
• Truncal involvement

Correct answer: Phymatous skin changes

Phymatous changes (e.g., rhinophyma) are specific to rosacea and do not occur in acne vulgaris.

Question 108: Which topical antifungal works by inhibiting ergosterol synthesis through blockade of lanosterol 14α-demethylase?

• Ciclopirox
• Ketoconazole (Correct answer)
• Terbinafine
• Nystatin

Correct answer: Ketoconazole

Azole antifungals like ketoconazole inhibit cytochrome P450-dependent lanosterol 14α-demethylase, blocking ergosterol synthesis and disrupting the fungal cell membrane.

Question 109: What is the recommended treatment for head lice (Pediculosis capitis) when permethrin 1% has failed?

• Oral ivermectin or topical spinosad/benzyl alcohol (Correct answer)
• Lindane shampoo
• Higher concentration permethrin
• Ketoconazole shampoo

Correct answer: Oral ivermectin or topical spinosad/benzyl alcohol

Resistance to permethrin is widespread; second-line options include oral ivermectin, topical spinosad (Natroba), or benzyl alcohol (Ulesfia), which work through different mechanisms.

Question 110: What is the mechanism by which UV radiation causes DNA damage leading to skin cancer?

• Direct strand breaks in double-stranded DNA
• Generation of reactive oxygen species only
• Deamination of cytosine to uracil
• Formation of cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts in DNA (Correct answer)

Correct answer: Formation of cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts in DNA

UVB radiation causes direct DNA damage by inducing formation of cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts between adjacent pyrimidine bases, causing characteristic C→T mutations.

Question 111: Kaposi sarcoma is associated with which herpesvirus, and which patient population is classically affected in epidemic KS?

• EBV; organ transplant recipients
• HHV-8 (KSHV); patients with advanced HIV/AIDS (Correct answer)
• HHV-6; elderly Mediterranean men
• CMV; immunosuppressed patients

Correct answer: HHV-8 (KSHV); patients with advanced HIV/AIDS

Human herpesvirus 8 (Kaposi sarcoma-associated herpesvirus) causes all forms of KS; epidemic KS affecting HIV-positive patients with AIDS was the most prevalent form during the AIDS epidemic.

Question 112: Which dermatophyte species is the most common cause of tinea capitis in the United States?

• Trichophyton tonsurans (Correct answer)
• Microsporum canis
• Epidermophyton floccosum
• Trichophyton rubrum

Correct answer: Trichophyton tonsurans

Trichophyton tonsurans is the predominant cause of tinea capitis in the US, especially in African American children.

Question 113: Which connective tissue disorder classically presents with a heliotrope rash around the eyes and Gottron's papules over the knuckles?

• Systemic sclerosis
• Systemic lupus erythematosus
• Mixed connective tissue disease
• Dermatomyositis (Correct answer)

Correct answer: Dermatomyositis

Dermatomyositis features a violaceous heliotrope rash on eyelids and Gottron's papules over the metacarpophalangeal joints, associated with proximal muscle weakness.

Question 114: A patient presents with pruritic, flesh-colored papules in a linear arrangement on the wrist and forearm after touching a plant. The pattern suggests which phenomenon?

• Phytophotodermatitis
• Dermatographism
• Blaschko's lines
• Koebner phenomenon (Correct answer)

Correct answer: Koebner phenomenon

The Koebner (isomorphic) phenomenon describes new lesions arising at sites of trauma or irritation, seen in conditions like lichen planus and psoriasis.

Question 115: What are moles that have the potential to turn into malignant melanoma?

• dysplastic nevi (Correct answer)
• verrucae
• giant nevi
• intraderma nevi

Correct answer: dysplastic nevi

Dysplastic nevi are atypical moles that have irregular borders, varied color, and are often larger than common moles. While most dysplastic nevi do not become melanoma, they are considered precursors to malignant melanoma and indicate an increased risk for developing this serious skin cancer. Regular monitoring by a dermatologist is crucial for individuals with these moles.

Question 116: Verocay bodies are a histological feature associated with which cutaneous tumor?

• Dermatofibroma
• Granular cell tumor
• Schwannoma (neurilemmoma) (Correct answer)
• Neurofibroma

Correct answer: Schwannoma (neurilemmoma)

Verocay bodies are palisading arrangements of Schwann cell nuclei around acellular fibrillar material (Antoni A areas), pathognomonic of schwannoma.

Question 117: In dermatopathology, 'spongiosis' refers to which histological finding?

• Loss of cell-to-cell cohesion in the epidermis
• Thickening of the stratum corneum
• Intercellular edema within the epidermis (Correct answer)
• Thinning of the granular layer

Correct answer: Intercellular edema within the epidermis

Spongiosis is intercellular edema between keratinocytes, causing the epidermis to appear sponge-like on histology and is the hallmark of eczematous dermatitis.

Question 118: Dermatitis herpetiformis is characterized by deposits of which immunoglobulin in the dermal papillae?

• IgA (Correct answer)
• IgE
• IgM
• IgG

Correct answer: IgA

Dermatitis herpetiformis shows granular IgA deposits in the dermal papillae on direct immunofluorescence, associated with celiac disease.

Question 119: What is the Breslow depth, and why is it the most important prognostic factor in primary melanoma?

• Distance from epidermis to nearest lymph node
• Depth of surgical excision needed
• Tumor thickness measured in mm from the granular layer to deepest tumor cell; predicts metastatic risk and survival (Correct answer)
• Clark level of dermal invasion

Correct answer: Tumor thickness measured in mm from the granular layer to deepest tumor cell; predicts metastatic risk and survival

Breslow depth is the vertical tumor thickness in millimeters measured by pathology, directly correlating with 5-year survival — thicker melanomas have greater access to lymphatics and blood vessels for metastasis.

Question 120: Atopy can be treated. True or False?

• False (Correct answer)
• True

Correct answer: False

Atopy, or atopic dermatitis, is a chronic, inherited allergic skin condition. While its symptoms can be managed with various treatments like medications, immunotherapy, and environmental control, there is currently no known cure for the underlying condition itself.

Question 121: Which finding on histopathology is pathognomonic for psoriasis?

• Munro microabscesses in the stratum corneum (Correct answer)
• Spongiosis with eosinophils
• Subepidermal blister with neutrophils
• Dyskeratotic cells at all levels

Correct answer: Munro microabscesses in the stratum corneum

Munro microabscesses — collections of neutrophils in the stratum corneum — are a pathognomonic histological feature of psoriasis.

Question 122: The Darier sign, elicited by stroking a lesion causing it to urticate and become raised, is pathognomonic for which condition?

• Mastocytosis (urticaria pigmentosa) (Correct answer)
• Dermatographism
• Bullous pemphigoid
• Lichen planus

Correct answer: Mastocytosis (urticaria pigmentosa)

Darier sign reflects mast cell degranulation in urticaria pigmentosa (cutaneous mastocytosis) upon physical stroking of the lesion.

Question 123: What is the Breslow thickness threshold above which sentinel lymph node biopsy is routinely recommended for melanoma?

• 0.5 mm
• 1.0 mm (Correct answer)
• 1.5 mm
• 0.8 mm

Correct answer: 1.0 mm

SLNB is routinely recommended for melanomas >1.0 mm Breslow thickness; it may be considered for 0.8–1.0 mm lesions with high-risk features.

Question 124: Civatte bodies (colloid/hyaline bodies) are characteristic of which dermatological condition?

• Dermatitis herpetiformis
• Lichen planus (Correct answer)
• Psoriasis
• Pemphigus vulgaris

Correct answer: Lichen planus

Civatte bodies are apoptotic keratinocytes (eosinophilic globules) seen at the dermal-epidermal junction in lichen planus due to interface dermatitis.

Question 125: A patient presents with targetoid lesions after starting trimethoprim-sulfamethoxazole. Mucosal involvement affects two sites. What is the diagnosis?

• Stevens-Johnson syndrome (Correct answer)
• Erythema multiforme major
• Toxic epidermal necrolysis
• Fixed drug eruption

Correct answer: Stevens-Johnson syndrome

Stevens-Johnson syndrome involves mucosal involvement at ≥2 sites with epidermal detachment affecting <10% of body surface area, often triggered by drugs.

Question 126: What is the most common type of skin cancer in the United States?

• Basal cell carcinoma (BCC) (Correct answer)
• Melanoma
• Merkel cell carcinoma
• Squamous cell carcinoma (SCC)

Correct answer: Basal cell carcinoma (BCC)

Basal cell carcinoma is the most common human malignancy, accounting for approximately 80% of all non-melanoma skin cancers and affecting millions of Americans annually.

Question 127: What is the term for excessive facial or body hair, especially in women?

• atrichia
• hirsutism (Correct answer)
• albinism
• alopecia

Correct answer: hirsutism

Hirsutism is a medical condition characterized by excessive growth of coarse, dark hair in a male-like pattern (e.g., on the face, chest, back) in women. It is typically caused by an excess of androgens (male hormones) or increased sensitivity of hair follicles to androgens. This differs from general hypertrichosis, which is excessive hair growth anywhere on the body.

Question 128: What is the primary cell type responsible for the inflammatory response in contact dermatitis?

• Plasma cells
• Neutrophils
• Mast cells
• CD4+ T lymphocytes (Th1/Th2 cells) (Correct answer)

Correct answer: CD4+ T lymphocytes (Th1/Th2 cells)

Allergic contact dermatitis is a Type IV (delayed-type) hypersensitivity reaction mediated by sensitized CD4+ T lymphocytes responding to the hapten-carrier complex.

Question 129: What is the recommended surgical margin for a primary melanoma with Breslow thickness between 1.01–2.0 mm?

• 3 cm wide local excision
• 0.5 cm wide local excision
• 5 mm punch excision
• 1–2 cm wide local excision (Correct answer)

Correct answer: 1–2 cm wide local excision

Current guidelines recommend 1–2 cm surgical margins for melanomas with Breslow thickness between 1.01 and 2.0 mm to achieve adequate local control.

Question 130: What is alopecia?

• Full or partial hair loss (Correct answer)
• Never where you want it to be
• Only full hair loss
• Difficult for men to deal with

Correct answer: Full or partial hair loss

Alopecia is the medical term for hair loss, which can manifest as either complete absence of hair in an area (full hair loss) or a thinning of hair (partial hair loss). It can affect any part of the body and have various underlying causes.

Question 131: A 60-year-old presents with a pearly, rolled border nodule on the nose with telangiectasias and central ulceration. What is the most likely diagnosis?

• Keratoacanthoma
• Merkel cell carcinoma
• Basal cell carcinoma (Correct answer)
• Squamous cell carcinoma

Correct answer: Basal cell carcinoma

A pearly nodule with rolled borders, telangiectasias, and central ulceration on sun-exposed skin of an older patient is classic for nodular basal cell carcinoma.

Question 132: Dermatofibrosarcoma protuberans (DFSP) is characterized by which genetic translocation?

• t(9;22) Philadelphia chromosome
• t(14;18) BCL2-IGH fusion
• t(17;22) resulting in COL1A1-PDGFB fusion gene (Correct answer)
• t(11;22) creating EWS-FLI1 fusion

Correct answer: t(17;22) resulting in COL1A1-PDGFB fusion gene

DFSP carries a translocation t(17;22) fusing COL1A1 and PDGFB, resulting in constitutive PDGF receptor activation, which is also the rationale for treating with imatinib (Gleevec).

Question 133: Seborrheic dermatitis preferentially affects which areas?

• Scalp, nasolabial folds, and central chest (Correct answer)
• Flexural creases and groin
• Lower legs and dorsal feet
• Dorsal hands and extensor surfaces

Correct answer: Scalp, nasolabial folds, and central chest

Seborrheic dermatitis affects sebum-rich areas including the scalp, face (nasolabial folds, eyebrows), and upper trunk due to Malassezia overgrowth.

Question 134: Photodynamic therapy (PDT) with aminolevulinic acid (ALA) is FDA-approved for treatment of which condition?

• Squamous cell carcinoma in situ (Bowen disease)
• Sebaceous hyperplasia
• Actinic keratoses (Correct answer)
• Nodular basal cell carcinoma

Correct answer: Actinic keratoses

PDT with ALA (Levulan) followed by blue or red light activation is FDA-approved for non-hyperkeratotic actinic keratoses on the face and scalp.

Question 135: A port-wine stain (nevus flammeus) on the face in a V1 trigeminal distribution should prompt evaluation for which syndrome?

• PHACE syndrome
• Sturge-Weber syndrome (Correct answer)
• Klippel-Trenaunay syndrome
• Beckwith-Wiedemann syndrome

Correct answer: Sturge-Weber syndrome

Port-wine stains in the V1 (ophthalmic) distribution of the trigeminal nerve are associated with Sturge-Weber syndrome, which includes ipsilateral leptomeningeal angioma, glaucoma, and seizures.

Question 136: Ash-leaf macules (hypopigmented macules), shagreen patches, and angiofibromas are cutaneous markers of which genodermatosis?

• LEOPARD syndrome
• Tuberous sclerosis complex (Correct answer)
• Neurofibromatosis type 2
• McCune-Albright syndrome

Correct answer: Tuberous sclerosis complex

Tuberous sclerosis complex presents with characteristic skin findings including ash-leaf macules (first sign), angiofibromas on the face, shagreen patches on the back, and periungual fibromas.

Question 137: A neonate develops a widespread vesiculopustular eruption within the first 2 weeks of life. Tzanck smear shows multinucleated giant cells. What is the diagnosis?

• Erythema toxicum neonatorum
• Neonatal candidiasis
• Neonatal herpes simplex (Correct answer)
• Transient neonatal pustular melanosis

Correct answer: Neonatal herpes simplex

Neonatal HSV presents with vesiculopustular eruption in the first weeks of life; Tzanck smear showing multinucleated giant cells confirms herpetic etiology.

Question 138: Which inflammatory cell type predominates in the histological findings of allergic contact dermatitis?

• Eosinophils
• Neutrophils
• Plasma cells
• Lymphocytes (Correct answer)

Correct answer: Lymphocytes

Allergic contact dermatitis is a type IV (delayed-type) hypersensitivity reaction mediated by T lymphocytes, which predominate in the perivascular dermal infiltrate.

Question 139: Which autoantibody is most specifically associated with pemphigus vulgaris?

• Anti-desmoglein 1
• Anti-laminin-332
• Anti-desmoglein 3 (Correct answer)
• Anti-BP180 (BPAG2)

Correct answer: Anti-desmoglein 3

Pemphigus vulgaris is caused by IgG antibodies against desmoglein 3, leading to acantholysis and suprabasal blisters.

Question 140: In which epidermal layer are melanocytes primarily located?

• Stratum basale (Correct answer)
• Stratum spinosum
• Stratum corneum
• Stratum granulosum

Correct answer: Stratum basale

Melanocytes reside in the stratum basale (basal layer), where they synthesize melanin and transfer it to surrounding keratinocytes via dendrites.

Question 141: Which of the following best describes the mechanism of action of isotretinoin in treating acne?

• Inhibits bacterial protein synthesis
• Blocks androgen receptors in follicles
• Increases epidermal turnover
• Reduces sebaceous gland size and sebum production (Correct answer)

Correct answer: Reduces sebaceous gland size and sebum production

Isotretinoin permanently reduces sebaceous gland size by up to 90%, dramatically decreasing sebum production and normalizing follicular keratinization.

Question 142: A teenager presents with open and closed comedones without inflammatory lesions. Which topical agent is most appropriate as first-line monotherapy?

• Benzoyl peroxide
• Topical clindamycin
• Topical tretinoin (Correct answer)
• Topical dapsone

Correct answer: Topical tretinoin

Topical retinoids like tretinoin are first-line for comedonal acne because they normalize follicular keratinization.

Question 143: What wood lamp finding is characteristic of erythrasma?

• No fluorescence
• Coral-red fluorescence (Correct answer)
• Blue-green fluorescence
• Yellow-green fluorescence

Correct answer: Coral-red fluorescence

Erythrasma, caused by Corynebacterium minutissimum, produces coral-red fluorescence under Wood lamp due to porphyrins produced by the bacteria.

Question 144: What is a skin condition characterized by red lesions that resemble targets and is typically brought on by the herpes virus?

• erythema multiforme
• keratosis pilaris
• hirsutism
• candidiasis

The correct answer is Erythema Multiforme. This skin condition is characterized by distinctive 'target lesions' (red lesions with a darker center and a pale ring), and it is frequently triggered by infections, most notably the herpes simplex virus.

Question 145: What is another word for itching?

• petechiae
• dermatitis
• pruritus (Correct answer)
• keratosis

Correct answer: pruritus

Pruritus is the medical term for itching, which is an unpleasant sensation that provokes the desire to scratch. It can be a symptom of various skin conditions, systemic diseases, allergic reactions, or even neurological disorders. Understanding the cause of pruritus is essential for effective treatment.

Question 146: A child presents with thick, hyperkeratotic plaques on the elbows, knees, and scalp with nail pitting. Which condition is most likely?

• Pityriasis rubra pilaris
• Childhood psoriasis (Correct answer)
• Tinea corporis
• Atopic dermatitis

Correct answer: Childhood psoriasis

Psoriasis in children presents similarly to adults with thick scaly plaques on extensor surfaces and scalp, and nail changes (pitting, onycholysis) are common associated findings.

Question 147: What term describes the genetic skin disorder characterized by absent or reduced melanin production due to tyrosinase deficiency?

• Chediak-Higashi syndrome
• Piebaldism
• Oculocutaneous albinism (Correct answer)
• Vitiligo

Correct answer: Oculocutaneous albinism

Oculocutaneous albinism results from mutations in genes such as TYR (tyrosinase), leading to absent or severely reduced melanin in skin, hair, and eyes.

Question 148: Which condition is characterized by thickened, yellow-green nails with slow growth and is associated with lymphedema and pleural effusion?

• Pachyonychia congenita
• Onychomycosis
• Yellow nail syndrome (Correct answer)
• Nail-patella syndrome

Correct answer: Yellow nail syndrome

Yellow nail syndrome is a rare disorder characterized by yellow, thickened, slow-growing nails associated with lymphedema and respiratory manifestations.

Question 149: Which skin finding is pathognomonic for Lyme disease?

• Migratory salmon-colored plaques
• Petechiae and purpura on lower extremities
• Vesiculobullous eruption following dermatome
• Erythema migrans — expanding annular erythema at tick bite site (Correct answer)

Correct answer: Erythema migrans — expanding annular erythema at tick bite site

Erythema migrans, the expanding bull's-eye or ring-shaped rash at the site of Borrelia burgdorferi-infected tick bite, is pathognomonic for early Lyme disease.

Question 150: Which topical calcineurin inhibitor is approved for use in children as young as 2 years old for atopic dermatitis?

• Pimecrolimus 1%
• Tacrolimus 0.1%
• Tacrolimus 0.03% (Correct answer)
• Crisaborole 2%

Correct answer: Tacrolimus 0.03%

Tacrolimus 0.03% ointment is approved for children aged 2–15 years, while the 0.1% formulation is reserved for adults.

Question 151: What kind of follicles do fur-bearing animals have?

• Compound (Correct answer)
• Intermediate
• Simple
• Fuzzy

Correct answer: Compound

Fur-bearing animals, such as dogs and cats, typically possess compound hair follicles. These follicles are unique because they produce multiple hairs (a primary guard hair and several secondary undercoat hairs) from a single pore, contributing to their dense fur coat.

Question 152: PD-1 checkpoint inhibitors (nivolumab, pembrolizumab) are approved for which stage of melanoma?

• Stage I thin melanoma
• Lentigo maligna melanoma only
• Advanced/metastatic melanoma and high-risk resected stage III/IV adjuvant therapy (Correct answer)
• In situ melanoma

Correct answer: Advanced/metastatic melanoma and high-risk resected stage III/IV adjuvant therapy

Anti-PD-1 immunotherapy is approved for unresectable or metastatic melanoma and as adjuvant therapy for high-risk resected stage III and stage IV melanoma to reduce recurrence.

Question 153: Which dermatological sign—a positive Nikolsky sign—is characterized by what response when lateral pressure is applied to normal-appearing skin?

• Blanching of erythema
• Darkening of the lesion
• Epidermal shearing and blister formation (Correct answer)
• Induration of the skin

Correct answer: Epidermal shearing and blister formation

A positive Nikolsky sign occurs when gentle lateral pressure causes the epidermis to slide or shear off, indicating fragile epidermal cohesion as in pemphigus.

Question 154: What is intralesional triamcinolone acetonide most commonly used to treat in dermatology?

• Epidermoid tumors
• Sebaceous cysts
• Keloids and hypertrophic scars (Correct answer)
• Basal cell carcinoma

Correct answer: Keloids and hypertrophic scars

Intralesional triamcinolone acetonide is the first-line treatment for keloids and hypertrophic scars, reducing collagen synthesis and inducing collagenase activity to flatten the scar.

Question 155: What historical skin treatment, involving wrapping patients in cloth soaked in coal tar, was standard therapy for psoriasis before modern biologics?

• Goeckerman regimen (Correct answer)
• PUVA therapy
• Ingram method
• Darier technique

Correct answer: Goeckerman regimen

The Goeckerman regimen combined crude coal tar application with UV light exposure and was a mainstay psoriasis treatment for decades.

Question 156: Subepidermal blisters with neutrophilic microabscesses in dermal papillae are histologically characteristic of which condition?

• Bullous pemphigoid
• Pemphigus vulgaris
• Dermatitis herpetiformis (Correct answer)
• Linear IgA bullous dermatosis

Correct answer: Dermatitis herpetiformis

Dermatitis herpetiformis shows subepidermal blisters with neutrophil-rich microabscesses at dermal papillae tips, corresponding to granular IgA deposits.

Question 157: Which vitamin, when severely deficient, causes pellagra with its classic triad of dermatitis, diarrhea, and dementia?

• Riboflavin (B2)
• Thiamine (B1)
• Niacin (B3) (Correct answer)
• Pyridoxine (B6)

Correct answer: Niacin (B3)

Pellagra results from niacin (vitamin B3) or tryptophan deficiency; the skin shows a photosensitive dermatitis in sun-exposed areas called casal necklace.

Question 158: A child presents with a 'strawberry tongue,' desquamating rash, and perioral pallor. What organism is responsible?

• Staphylococcus aureus
• Group A Streptococcus (Correct answer)
• Haemophilus influenzae
• Neisseria meningitidis

Correct answer: Group A Streptococcus

Scarlet fever is caused by Group A Streptococcus producing erythrogenic toxins, leading to the classic rash and strawberry tongue.

Question 159: Which topical medication is first-line for rosacea papulopustular subtype?

• Topical metronidazole (Correct answer)
• Topical mupirocin
• Topical betamethasone
• Topical tretinoin

Correct answer: Topical metronidazole

Topical metronidazole is a first-line treatment for papulopustular rosacea due to its anti-inflammatory and antimicrobial properties.

Question 160: A patient taking methotrexate for psoriasis develops oral ulcers and cytopenias. Which supplement should be co-administered to reduce toxicity?

• Zinc
• Vitamin B12
• Folic acid (Correct answer)
• Vitamin D

Correct answer: Folic acid

Folic acid supplementation reduces methotrexate-related side effects including mucositis and bone marrow suppression without significantly reducing efficacy.

Question 161: Acantholysis, the disruption of cell-to-cell adhesion between keratinocytes, is a hallmark histological finding in which condition?

• Epidermolysis bullosa
• Bullous pemphigoid
• Pemphigus vulgaris (Correct answer)
• Dermatitis herpetiformis

Correct answer: Pemphigus vulgaris

Pemphigus vulgaris features intraepidermal acantholysis due to IgG autoantibodies against desmoglein 3, causing suprabasal blisters with 'tombstone' basal cells.

Question 162: What is the most common cause of tinea capitis in the United States?

• Trichophyton rubrum
• Microsporum canis
• Epidermophyton floccosum
• Trichophyton tonsurans (Correct answer)

Correct answer: Trichophyton tonsurans

Trichophyton tonsurans is responsible for the majority of tinea capitis cases in the US, particularly in school-aged children of African American descent.

Question 163: What is the recommended first-line topical treatment for localized superficial basal cell carcinoma?

• Imiquimod 5% cream (Correct answer)
• Tretinoin cream
• Diclofenac gel
• 5-fluorouracil cream

Correct answer: Imiquimod 5% cream

Imiquimod 5% cream is FDA-approved for superficial BCC and works as an immune response modifier stimulating innate and adaptive immunity against tumor cells.

Question 164: Which skin condition is characterized by silvery-white plaques with well-defined borders most commonly found on the elbows and knees?

• Vitiligo
• Rosacea
• Psoriasis (Correct answer)
• Eczema

Correct answer: Psoriasis

Psoriasis presents as thick, silvery-white scaly plaques with sharply demarcated borders, classically on extensor surfaces like elbows and knees.

Question 165: Ivermectin 1% cream is approved for topical treatment of which skin condition?

• Scabies
• Demodicosis
• Rosacea (papulopustular subtype) (Correct answer)
• Pediculosis capitis

Correct answer: Rosacea (papulopustular subtype)

Topical ivermectin 1% cream (Soolantra) is FDA-approved for inflammatory lesions of rosacea, working through anti-inflammatory effects and reduction of Demodex mite burden.

Question 166: Which Wood's lamp finding is associated with erythrasma?

• Coral-red fluorescence (Correct answer)
• Bright green fluorescence
• No fluorescence
• Blue-white fluorescence

Correct answer: Coral-red fluorescence

Erythrasma caused by Corynebacterium minutissimum produces coral-red fluorescence under Wood's lamp due to porphyrin production.

Question 167: Xeroderma pigmentosum (XP) results from defects in which cellular repair mechanism?

• Homologous recombination
• Mismatch repair
• Nucleotide excision repair (NER) of UV-induced DNA damage (Correct answer)
• Base excision repair

Correct answer: Nucleotide excision repair (NER) of UV-induced DNA damage

XP is caused by inherited mutations in nucleotide excision repair genes, leaving UV-induced pyrimidine dimers unrepaired, leading to early and multiple skin cancers and photosensitivity.

Question 168: Which term describes the benign, dome-shaped, skin-colored papule that undergoes central umbilication and spontaneous resolution, caused by a poxvirus?

• Sebaceous hyperplasia
• Molluscum contagiosum (Correct answer)
• Milia
• Verruca vulgaris

Correct answer: Molluscum contagiosum

Molluscum contagiosum is caused by a poxvirus and presents as umbilicated papules that typically self-resolve within months to years.

Question 169: The term 'lichenification' refers to which morphological skin change caused by chronic rubbing or scratching?

• Thickened, exaggerated skin markings with a leathery texture (Correct answer)
• Fluid-filled cavity within the epidermis
• Flat, non-palpable color change
• Loss of epidermis exposing the dermis

Correct answer: Thickened, exaggerated skin markings with a leathery texture

Lichenification describes thickened, leathery skin with accentuated surface markings, resulting from prolonged rubbing or scratching in conditions like atopic dermatitis.

Question 170: What is the most common site of origin for lentigo maligna melanoma?

• Sun-damaged skin of the head and neck in elderly patients (Correct answer)
• Mucosal surfaces
• Posterior trunk
• Acral surfaces of hands and feet

Correct answer: Sun-damaged skin of the head and neck in elderly patients

Lentigo maligna melanoma develops from lentigo maligna (melanoma in situ) on chronically sun-damaged skin, most commonly on the face of elderly individuals.

Question 171: Tinea versicolor is caused by which organism?

• Malassezia furfur (Correct answer)
• Candida albicans
• Epidermophyton floccosum
• Trichophyton rubrum

Correct answer: Malassezia furfur

Tinea versicolor (pityriasis versicolor) is caused by the dimorphic yeast Malassezia furfur, part of normal skin flora.

Question 172: What is the indication of pemphigus foliceus?

• Very young puppies
• Elderly animals
• Any age
• Young to middle age adults (Correct answer)

Correct answer: Young to middle age adults

Pemphigus foliaceus is an autoimmune skin disease that can affect various age groups, but it is most commonly diagnosed in young to middle-aged adult animals. It causes characteristic crusting and erosions, particularly on the face and ears.

Question 173: A virus-induced epidermal growth is referred to as a?

• impetigo
• melanoma
• nevus
• verruca (Correct answer)

Correct answer: verruca

A verruca, commonly known as a wart, is a small, rough growth on the skin or mucous membrane caused by a viral infection, specifically by the human papillomavirus (HPV). These growths are benign and can appear anywhere on the body, varying in size and shape depending on the type of HPV and location.

Question 174: Which Nobel Prize-winning discovery led to widespread use of UV radiation in dermatology?

• Wilhelm Röntgen's X-rays
• Marie Curie's discovery of radium
• Niels Finsen's phototherapy for lupus vulgaris (Correct answer)
• Alexander Fleming's penicillin

Correct answer: Niels Finsen's phototherapy for lupus vulgaris

Niels Finsen won the 1903 Nobel Prize in Medicine for treating lupus vulgaris with concentrated UV light, founding phototherapy.

Question 175: What is the name of a crack or groove-like sore?

• fissure (Correct answer)
• nodule
• polyp
• ulcer

Correct answer: fissure

In dermatology, a fissure is defined as a linear crack or break in the skin that extends into the dermis. These lesions are often painful and can occur in areas of thickened, dry, or inflamed skin. Unlike an ulcer, which is a deeper open sore, a fissure is typically a narrow, groove-like defect.

Question 176: Chemical peels using trichloroacetic acid (TCA) at 30–40% penetrate to which skin layer?

• Papillary to upper reticular dermis (Correct answer)
• Stratum corneum only
• Deep reticular dermis
• Subcutaneous fat

Correct answer: Papillary to upper reticular dermis

Medium-depth TCA peels at 30–40% penetrate through the epidermis to the papillary and upper reticular dermis, making them effective for actinic keratoses and dyspigmentation.

Question 177: Which of the following treatments for acne would be recommended?

• Actonel
• Accutane (Correct answer)
• Actiq
• Accu-Check

Correct answer: Accutane

Accutane (isotretinoin) is a powerful prescription medication commonly recommended by dermatologists for severe, recalcitrant nodular acne that has not responded to other treatments. It works by significantly reducing the size and activity of sebaceous glands, thereby decreasing oil production and preventing clogged pores. The other options are not treatments for acne.

Question 178: What feature of melanoma on dermoscopy is most specific for malignancy?

• Blue-white veil overlying raised areas (Correct answer)
• Uniform pigment network
• Symmetrical globules
• Regular dermoscopic structures

Correct answer: Blue-white veil overlying raised areas

The blue-white veil — an irregular, structureless, ground-glass blue area with overlying white haze — is a dermoscopic feature highly specific for invasive melanoma.

Question 179: Which type of hypersensitivity reaction is responsible for allergic contact dermatitis?

• Type IV (cell-mediated) (Correct answer)
• Type II (cytotoxic)
• Type I (IgE-mediated)
• Type III (immune complex)

Correct answer: Type IV (cell-mediated)

Allergic contact dermatitis is a Type IV delayed hypersensitivity reaction mediated by sensitized T lymphocytes, typically occurring 48–72 hours after exposure.

Question 180: Which US state became the first to ban commercial tanning beds for minors under 18, paving the way for similar legislation nationwide?

• California (Correct answer)
• New York
• Texas
• Florida

Correct answer: California

California became the first US state to ban indoor tanning for minors under 18 in 2011, citing increased melanoma risk.

Question 181: The 'ABCDE' criteria for melanoma evaluation stands for asymmetry, border, color, diameter, and what fifth feature added later?

• Evolving (Correct answer)
• Erosion
• Elevation
• Erythema

Correct answer: Evolving

The 'E' in ABCDE was later defined as 'evolving,' meaning any change in size, shape, color, or new symptom over time warrants evaluation.

Question 182: Which histochemical stain is most useful for identifying amyloid deposits in the skin, and what is its characteristic finding under polarized light?

• Masson trichrome showing green collagen
• Alcian blue showing blue mucin deposits
• PAS stain showing magenta coloration
• Congo red stain showing apple-green birefringence (Correct answer)

Correct answer: Congo red stain showing apple-green birefringence

Congo red staining with apple-green birefringence under polarized light is the gold standard for identifying amyloid deposits in skin and other tissues.

Question 183: What is the purpose of patch testing in dermatology?

• To identify specific allergens causing allergic contact dermatitis (Correct answer)
• To diagnose irritant contact dermatitis
• To detect immediate IgE-mediated hypersensitivity reactions
• To confirm atopic dermatitis diagnosis

Correct answer: To identify specific allergens causing allergic contact dermatitis

Patch testing (epicutaneous testing) identifies specific causative allergens in type IV delayed hypersensitivity reactions responsible for allergic contact dermatitis.

Question 184: Which mite is responsible for scabies infestation?

• Sarcoptes scabiei var. hominis (Correct answer)
• Dermanyssus gallinae
• Cheyletiella species
• Demodex folliculorum

Correct answer: Sarcoptes scabiei var. hominis

Scabies is caused by the human itch mite Sarcoptes scabiei var. hominis, which burrows into the stratum corneum causing intense pruritus, especially at night.

Question 185: Impetigo caused by Staphylococcus aureus most characteristically produces which type of lesion?

• Deep nodular abscesses
• Vesicles following a dermatomal pattern
• Honey-colored crusted lesions and bullae from exfoliative toxins (Correct answer)
• Erythematous targetoid plaques

Correct answer: Honey-colored crusted lesions and bullae from exfoliative toxins

Staphylococcal impetigo produces the classic honey-colored crusted lesions; bullous impetigo results from exfoliative toxins A and B causing superficial epidermal cleavage at the granular layer.

Question 186: The white, half-moon-shaped region at the end of a fingernail is referred to as the?

• stratum
• lunula (Correct answer)
• cuticle
• basal layer

Correct answer: lunula

The lunula is the visible, white, half-moon-shaped area at the base of the fingernail or toenail. It is the visible part of the nail matrix, where new nail cells are produced. Its white appearance is due to the thickness of the nail matrix obscuring the blood vessels underneath.

Question 187: Livedo reticularis presenting with systemic thrombosis and recurrent pregnancy loss suggests which underlying condition?

• Polyarteritis nodosa
• Cryoglobulinemia
• Antiphospholipid syndrome (Correct answer)
• Livedoid vasculopathy

Correct answer: Antiphospholipid syndrome

The combination of livedo reticularis, arterial or venous thrombosis, and recurrent pregnancy loss is the classic triad of antiphospholipid antibody syndrome.

Question 188: A 'Grenz zone' on dermatopathology refers to which histological finding?

• A clear halo surrounding a tumor nest
• The zone of acanthosis seen in psoriasis
• The normal papillary dermis in unaffected skin
• A band of spared papillary dermis between the epidermis and a dermal infiltrate (Correct answer)

Correct answer: A band of spared papillary dermis between the epidermis and a dermal infiltrate

The Grenz zone is a narrow band of normal papillary dermis separating the overlying epidermis from the underlying inflammatory or neoplastic infiltrate, often seen in lepromatous leprosy and some lymphomas.

Question 189: A newborn presents with vesicles and pustules on an erythematous base distributed over the trunk, face, and extremities. Smear shows eosinophils. What is the diagnosis?

• Neonatal herpes simplex
• Erythema toxicum neonatorum (Correct answer)
• Staphylococcal scalded skin syndrome
• Transient neonatal pustular melanosis

Correct answer: Erythema toxicum neonatorum

Erythema toxicum neonatorum is a benign self-limiting eruption in newborns characterized by eosinophils on smear.

Question 190: A 70-year-old woman has tense bullae on uninflamed skin of the thighs and lower abdomen. DIF shows linear IgG and C3 at the dermoepidermal junction. What is the diagnosis?

• Bullous pemphigoid (Correct answer)
• Pemphigus vulgaris
• Dermatitis herpetiformis
• Linear IgA bullous dermatosis

Correct answer: Bullous pemphigoid

Bullous pemphigoid presents with tense subepidermal bullae and linear IgG/C3 at the BMZ on DIF, targeting BP180 and BP230.

Question 191: What is the role of dermoscopy (dermatoscopy) in skin cancer diagnosis?

• Real-time imaging of dermal collagen fibers
• Magnified visualization of subsurface skin structures to improve diagnostic accuracy of pigmented lesions (Correct answer)
• Spectroscopic analysis of melanin content
• In vivo confocal microscopy of cellular architecture

Correct answer: Magnified visualization of subsurface skin structures to improve diagnostic accuracy of pigmented lesions

Dermoscopy uses polarized or immersion light to visualize structures in the epidermis and superficial dermis invisible to the naked eye, significantly improving melanoma detection rates.

Question 192: What is the hallmark clinical feature of atopic dermatitis (eczema) in adults?

• Depigmented macules on sun-exposed skin
• Annular scaling patches on the trunk
• Vesicular eruption on palms and soles
• Lichenification and pruritus in flexural areas (Correct answer)

Correct answer: Lichenification and pruritus in flexural areas

Adult atopic dermatitis typically presents with lichenification and intense itching in flexural areas such as the antecubital and popliteal fossae.

Question 193: The Auspitz sign, elicited by removing a psoriatic scale and seeing pinpoint bleeding, reflects what underlying histological feature?

• Dermal neutrophilic infiltrate
• Acanthosis of the epidermis
• Dilated tortuous capillaries in elongated dermal papillae (Correct answer)
• Parakeratosis of the stratum corneum

Correct answer: Dilated tortuous capillaries in elongated dermal papillae

Auspitz sign results from the very thin suprapapillary plate in psoriasis; removing scale exposes the engorged capillary tips, causing punctate bleeding.

Question 194: Solar elastosis is characterized by which histological finding in the dermis?

• Granulomatous inflammation with giant cells
• Increased fibrotic collagen deposition
• Basophilic degeneration and clumping of elastic fibers (Correct answer)
• Mucin deposition in the reticular dermis

Correct answer: Basophilic degeneration and clumping of elastic fibers

Solar elastosis results from chronic UV exposure causing abnormal production and degeneration of elastic fibers, which appear basophilic/amphophilic and clumped on H&E staining.

Question 195: The skin's outermost layer is called the?

• epidermis (Correct answer)
• endodermis
• dermis
• hypodermis

Correct answer: epidermis

The epidermis is the outermost protective layer of the skin. It acts as a crucial barrier against water loss, pathogens, and environmental damage. This layer is primarily composed of keratinocytes and is responsible for producing melanin, which gives skin its color and protects against UV radiation.

Question 196: Which histological finding is considered pathognomonic of psoriasis?

• Flame figures
• Pautrier microabscesses
• Munro microabscesses (Correct answer)
• Civatte bodies

Correct answer: Munro microabscesses

Munro microabscesses are collections of neutrophils within the parakeratotic stratum corneum and are pathognomonic of psoriasis.

Question 197: What is the primary pathological finding in bullous pemphigoid?

• IgG autoantibodies targeting BP180 and BP230 at the dermoepidermal junction (Correct answer)
• IgG autoantibodies targeting desmoglein 1 and 3
• T-cell mediated destruction of basal keratinocytes
• IgA deposits in dermal papillae

Correct answer: IgG autoantibodies targeting BP180 and BP230 at the dermoepidermal junction

Bullous pemphigoid is caused by IgG autoantibodies against BP180 (collagen XVII) and BP230, proteins of the hemidesmosome at the dermoepidermal junction.

Question 198: What kind of cyst typically develops on the vulva, scrotum, and scalp and includes yellowish sebum?

• sebaceous cyst (Correct answer)
• vesicle
• papule
• ulcer

Correct answer: sebaceous cyst

A sebaceous cyst, also known as an epidermoid cyst, is a common non-cancerous cyst that arises from a blocked sebaceous gland or hair follicle. These cysts typically contain a yellowish, cheesy, or oily substance (sebum) and are frequently found on areas with many sebaceous glands, such as the scalp, face, neck, back, and sometimes the vulva or scrotum.

Question 199: Which skin condition in pregnancy presents with intensely pruritic urticarial papules and plaques in the striae of the abdomen?

• Atopic eruption of pregnancy
• Pemphigoid gestationis
• Intrahepatic cholestasis of pregnancy
• PUPPP (Pruritic Urticarial Papules and Plaques of Pregnancy) (Correct answer)

Correct answer: PUPPP (Pruritic Urticarial Papules and Plaques of Pregnancy)

PUPPP (also called polymorphic eruption of pregnancy) classically begins in the abdominal striae of primigravida women in the third trimester, sparing the umbilicus.

Question 200: What is the term for a lack of colour in the skin?

• melanism
• acanthosis nigricans
• xanthoderma
• albinism (Correct answer)

Correct answer: albinism

Albinism is a congenital condition characterized by a complete or partial absence of pigment in the skin, hair, and eyes. This lack of melanin, the pigment responsible for color, results in very pale skin, white hair, and often light-colored eyes. It is a genetic disorder affecting melanin production pathways.