Certified Dermatology Tech (CDT) — Questions and Answers
Question 1: During a skin assessment, a technician notes 'telangiectasias.' These are best described as:
- Dilated superficial blood vessels visible through the skin (Correct answer)
- Small subcutaneous hemorrhages
- Yellow fatty deposits beneath the skin
- White macular lesions indicating depigmentation
Correct answer: Dilated superficial blood vessels visible through the skin
Telangiectasias are permanently dilated small superficial blood vessels visible as red or purple linear marks on the skin surface.
Question 2: A slit-skin smear is primarily used to diagnose which condition?
- Psoriasis
- Dermatitis herpetiformis
- Pemphigus vulgaris
- Leprosy (Correct answer)
Correct answer: Leprosy
Slit-skin smears are used to detect Mycobacterium leprae in tissue fluid from incised skin sites to diagnose and classify leprosy.
Question 3: Which dermatophyte infection specifically affects the nails?
- Onychomycosis (Correct answer)
- Tinea versicolor
- Tinea corporis
- Tinea pedis
Correct answer: Onychomycosis
Onychomycosis is fungal infection of the nails, causing thickening, discoloration, and brittleness.
Question 4: A technician performing a patch test for contact allergy reads results at 48 and 96 hours. A '+' (weakly positive) reaction is characterized by:
- Bullae formation with necrosis
- Spreading reaction beyond the patch site
- Erythema, edema, and small papules (Correct answer)
- Non-palpable erythema only
Correct answer: Erythema, edema, and small papules
A single-plus patch test reaction shows erythema, edema, and small papules, indicating a mild allergic contact sensitization to the test allergen.
Question 5: What is the Minimal Erythema Dose (MED) used to determine in phototherapy?
- Safe starting UV dose for treatment (Correct answer)
- Frequency of treatment sessions
- Amount of psoralen to prescribe
- Maximum safe topical steroid dose
Correct answer: Safe starting UV dose for treatment
The MED is the lowest UV dose producing minimal redness at 24 hours, used to calculate a safe and individualized starting phototherapy dose.
Question 6: Transmission-based precautions for varicella (chickenpox) in a dermatology clinic include:
- Airborne and contact precautions (Correct answer)
- Contact precautions only
- Droplet precautions only
- Standard precautions only
Correct answer: Airborne and contact precautions
Varicella spreads via both airborne droplet nuclei and direct contact with lesions, requiring both airborne and contact precautions.
Question 7: Which hallmark sign is used to diagnose pemphigus vulgaris at the bedside, where lateral pressure on unblistered skin causes shearing of the epidermis?
- Asboe-Hansen sign
- Nikolsky sign (Correct answer)
- Fitzpatrick sign
- Darier sign
Correct answer: Nikolsky sign
A positive Nikolsky sign, elicited by applying lateral shear pressure to normal-appearing skin to produce blistering, is characteristic of pemphigus vulgaris.
Question 8: Phototesting (MED determination) measures the minimum erythema dose. This test is used to:
- Assess skin cancer risk by pigmentation typing
- Diagnose fungal scalp infections
- Determine a patient's UV sensitivity threshold for phototherapy dosing (Correct answer)
- Identify allergens causing contact dermatitis
Correct answer: Determine a patient's UV sensitivity threshold for phototherapy dosing
The MED test exposes skin to incremental UV doses to find the lowest dose causing perceptible erythema, guiding safe and effective phototherapy treatment initiation.
Question 9: Which statement about alcohol-based hand rubs (ABHR) in dermatology is CORRECT?
- ABHR should contain at least 60% alcohol to be effective (Correct answer)
- ABHR is effective against Clostridioides difficile spores
- ABHR is preferred over soap and water when hands are visibly soiled
- ABHR requires rinsing with water after application
Correct answer: ABHR should contain at least 60% alcohol to be effective
The CDC recommends hand sanitizers containing at least 60% alcohol to effectively kill most pathogens; lower concentrations may not be as effective.
Question 10: The Langerhans cells found in the epidermis function primarily as:
- Melanin producers
- Keratin synthesizers
- Antigen-presenting immune cells (Correct answer)
- Tactile receptors
Correct answer: Antigen-presenting immune cells
Langerhans cells are dendritic antigen-presenting cells that play a key role in the skin's immune surveillance.
Question 11: Which antibiotic class used in dermatology requires patients to use sunscreen due to photosensitivity?
- Oral tetracyclines (doxycycline, minocycline) (Correct answer)
- Oral antihistamines
- Topical calamine lotion
- Topical hydrocortisone
Correct answer: Oral tetracyclines (doxycycline, minocycline)
Oral tetracyclines cause photosensitivity reactions, requiring patients to apply broad-spectrum sunscreen and minimize direct sun exposure during treatment.
Question 12: What type of lesion is associated with psoriasis?
- Crusty pustules
- Fluid-filled vesicles
- Scaly plaques (Correct answer)
- Ulcerations
Correct answer: Scaly plaques
Psoriasis is a chronic autoimmune condition characterized by the rapid overproduction of skin cells, leading to thick, red patches covered with silvery scales, known as plaques. These plaques are typically well-demarcated and can appear on various parts of the body.
Question 13: What type of collagen predominates in the reticular dermis and provides tensile strength to the skin?
- Type I collagen (Correct answer)
- Type IV collagen
- Type VII collagen
- Type III collagen
Correct answer: Type I collagen
Type I collagen is the most abundant collagen in the reticular dermis and is responsible for the skin's tensile strength.
Question 14: According to the ICDRG grading system, what does a '++' reaction indicate?
- Strong positive with erythema, infiltration, and vesicles (Correct answer)
- Extreme positive reaction with bullae
- Doubtful reaction with faint erythema only
- Weak positive with erythema and mild infiltration
Correct answer: Strong positive with erythema, infiltration, and vesicles
In the ICDRG scale, '++' (strong positive) indicates erythema, infiltration, papules, and vesicles at the patch test site.
Question 15: Which skin finding is most characteristic of tuberous sclerosis complex?
- Neurofibromata
- Ash-leaf macules (hypomelanotic macules) (Correct answer)
- Café-au-lait macules
- Shagreen patches only
Correct answer: Ash-leaf macules (hypomelanotic macules)
Ash-leaf macules (hypomelanotic macules visible under Wood's lamp) are the earliest and most common cutaneous sign of tuberous sclerosis complex, often present at birth.
Question 16: The stratum lucidum is found exclusively in which body locations?
- Palms and soles (Correct answer)
- Back and abdomen
- Face and neck
- Scalp and axillae
Correct answer: Palms and soles
The stratum lucidum is an additional clear epidermal layer found only in the thick skin of palms and soles, providing extra protection in high-pressure areas.
Question 17: How does the skin participate in immune defense?
- By producing antibodies
- Via sweat production
- Through Langerhans cells (Correct answer)
- By secreting melanin
Correct answer: Through Langerhans cells
Langerhans cells are specialized dendritic cells found in the epidermis. They are a crucial part of the skin's immune system, acting as antigen-presenting cells that capture and process foreign antigens, then migrate to lymph nodes to initiate an immune response.
Question 18: When a patient's guardian requests to see the minor patient's dermatology records, the tech should:
- Deny the request because minors have full medical privacy rights
- Release only billing records, not clinical notes
- Verify the guardian's legal authority before releasing any records (Correct answer)
- Provide all records immediately without verification
Correct answer: Verify the guardian's legal authority before releasing any records
Before releasing a minor's records to any third party, staff must verify legal guardianship or parental rights to ensure compliance with HIPAA and state law.
Question 19: A patient asks the tech to skip the consent form because they've 'had this done before.' The appropriate response is:
- Insist on signed informed consent regardless of history (Correct answer)
- Obtain verbal consent and document it in the chart
- Proceed since prior consent implies ongoing consent
- Ask the provider to handle the situation
Correct answer: Insist on signed informed consent regardless of history
Informed consent must be obtained for each separate procedure or visit; prior consent does not carry forward to new encounters.
Question 20: A dermoscopy examination reveals a 'blue-white veil' structure. This finding is most associated with:
- Basal cell carcinoma
- Melanoma (Correct answer)
- Dermatofibroma
- Seborrheic keratosis
Correct answer: Melanoma
A blue-white veil in dermoscopy is a significant marker associated with melanoma, representing a confluent blue-white color over a raised area of the lesion.
Question 21: What is the primary purpose of applying a coupling gel during an ultrasound-based skin tightening procedure such as Ultherapy?
- To anesthetize the skin surface
- To prevent post-procedure hyperpigmentation
- To facilitate ultrasound wave transmission and skin contact (Correct answer)
- To dilute the ultrasound energy for safety
Correct answer: To facilitate ultrasound wave transmission and skin contact
Coupling gel eliminates air gaps between the transducer and skin, allowing efficient ultrasound energy transmission to the target tissue depth.
Question 22: The papillary dermis differs from the reticular dermis in that it contains:
- Thick elastic fibers only
- Loose connective tissue and capillary loops (Correct answer)
- Adipocytes and large vessels
- Densely packed Type I collagen bundles
Correct answer: Loose connective tissue and capillary loops
The papillary dermis is composed of loose connective tissue with capillary loops that nourish the avascular epidermis.
Question 23: Which of the following is the most common site of melanoma in males in the United States?
- Trunk (back) (Correct answer)
- Upper extremities
- Lower extremities
- Head and neck
Correct answer: Trunk (back)
In males, the trunk—particularly the back—is the most common anatomical location for melanoma in the United States.
Question 24: Which vehicle type is most appropriate for delivering medication to a hairy area of the body?
- Ointment
- Cream
- Paste
- Solution or lotion (Correct answer)
Correct answer: Solution or lotion
Solutions and lotions are preferred for hairy areas because they penetrate hair follicles more easily and are less occlusive than thicker formulations.
Question 25: Which immunofluorescence pattern is classically associated with pemphigus vulgaris on direct immunofluorescence (DIF)?
- Linear IgG along the basement membrane zone
- Homogeneous IgM deposits in the dermis
- Intercellular IgG in a 'fishnet' pattern throughout the epidermis (Correct answer)
- Granular IgA in dermal papillae
Correct answer: Intercellular IgG in a 'fishnet' pattern throughout the epidermis
Pemphigus vulgaris shows intercellular IgG deposits between keratinocytes in a characteristic 'fishnet' or 'chicken-wire' pattern on DIF.
Question 26: A tech observes a coworker reusing a single-use lancet on a second patient. The correct ethical action is:
- Document it privately without reporting
- Intervene immediately and report the incident per facility policy (Correct answer)
- Ignore it because the coworker is experienced
- Ask the patient if they consent to the reused device
Correct answer: Intervene immediately and report the incident per facility policy
Patient safety requires immediate intervention and reporting when a single-use device is reused, regardless of the colleague's experience level.
Question 27: Which viral condition often appears as grouped blisters?
- Herpes simplex (Correct answer)
- Ringworm
- Eczema
- Psoriasis
Correct answer: Herpes simplex
Herpes simplex virus (HSV) infections, such as cold sores (HSV-1) or genital herpes (HSV-2), are characterized by the appearance of small, painful, fluid-filled blisters that often occur in clusters or groups on a red base. These vesicles eventually rupture, crust over, and heal.
Question 28: Which condition is narrowband UVB phototherapy most commonly used to treat?
- Psoriasis (Correct answer)
- Acne vulgaris
- Rosacea
- Seborrheic dermatitis
Correct answer: Psoriasis
Narrowband UVB is most commonly used for psoriasis, and is also effective for vitiligo and atopic dermatitis.
Question 29: When assisting with a chemical peel, what is the correct action if the patient reports extreme burning beyond the expected sensation during a medium-depth TCA peel?
- Apply more neutralizer immediately
- Fan the area and encourage deep breathing
- Notify the supervising physician and prepare to neutralize (Correct answer)
- Document the complaint and continue the procedure
Correct answer: Notify the supervising physician and prepare to neutralize
Unexpected intense burning may indicate excessive penetration; the dermatology tech must alert the physician immediately while being prepared to neutralize.
Question 30: Meissner's corpuscles are sensory receptors primarily located in which skin region?
- Hypodermis
- Sebaceous glands
- Stratum corneum
- Dermal papillae of hairless skin (Correct answer)
Correct answer: Dermal papillae of hairless skin
Meissner's corpuscles are encapsulated mechanoreceptors found in the dermal papillae of glabrous (hairless) skin, detecting light touch.
Question 31: The Tzanck smear is a rapid diagnostic test used primarily to identify:
- Fungal hyphae in dermatophytosis
- Melanocytes in melanoma
- Bacterial cocci in impetigo
- Multinucleated giant cells in herpesvirus infections (Correct answer)
Correct answer: Multinucleated giant cells in herpesvirus infections
The Tzanck smear identifies multinucleated giant cells (viral cytopathic effect) from the base of herpetic vesicles, confirming HSV or VZV infection.
Certified Dermatology Tech (CDT)
The CDT certification, offered by the Association of Certified Dermatology Techs (ACDT), validates the knowledge and skills of dermatology clinical staff across two levels: Level I covering essentials such as skin anatomy, medications, and infection control, and Level II covering advanced topics including skin conditions, lab procedures, and cosmetic dermatology.
Exam Rules
- You can skip questions and return to them later
- Flag questions for review before submitting
- No feedback shown until you submit the entire exam
- Unanswered questions count as wrong — answer everything
- 10 pretest questions are mixed in and don't affect your score
- Timer auto-submits when time runs out
- Your progress is auto-saved every 30 seconds