Mixed Deck — All Dermatologist Certificate Topics Flashcards

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

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.

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

Answer: Folic acid

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

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

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.

What wood lamp finding is characteristic of erythrasma?

Answer: Coral-red fluorescence

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

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

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.

Which dermatological condition is associated with Nikolsky sign — skin separation with lateral pressure?

Answer: Pemphigus vulgaris

A positive Nikolsky sign, where gentle lateral pressure causes skin to shear and blister, is classically associated with pemphigus vulgaris due to loss of intraepidermal cohesion.

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

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.

Which gene is most commonly mutated in patients with familial melanoma?

Answer: CDKN2A

CDKN2A (encoding p16/INK4A) is the most commonly mutated gene in familial melanoma, significantly increasing lifetime risk.

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

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.

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

Answer: Lymphocytes

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

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

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.

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

Answer: Dermatitis herpetiformis

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

What is the most common primary malignant skin tumor worldwide by incidence?

Answer: Basal cell carcinoma

Basal cell carcinoma is the most common human cancer overall, accounting for approximately 80% of all non-melanoma skin cancers.

What makes ARF different from FAD?

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.

What is the purpose of patch testing in dermatology?

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.

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

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.

In dermatopathology, 'spongiosis' refers to which histological finding?

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.

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

Answer: Trichophyton tonsurans

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

Which layer of the epidermis contains the highest concentration of melanocytes?

Answer: Stratum basale

Melanocytes reside primarily in the stratum basale (basal layer), where they transfer melanin to surrounding keratinocytes.

Which type of skin cancer has the highest rate of metastasis?

Answer: Merkel cell carcinoma

Merkel cell carcinoma is a rare but aggressive neuroendocrine skin cancer with high rates of local recurrence, nodal spread, and distant metastasis.