Family Practice Exam Dermatology 4 — Questions and Answers
Question 1: A 48-year-old woman presents with hypopigmented macules on the face and neck that do not tan in summer. Wood's lamp examination shows enhanced pigmentation of surrounding normal skin. KOH is negative. What is the diagnosis?
- Vitiligo (Correct answer)
- Pityriasis versicolor
- Post-inflammatory hypopigmentation
- Leprosy
Correct answer: Vitiligo
Vitiligo shows chalk-white depigmented macules that fluoresce under Wood's lamp due to enhanced contrast with surrounding skin; KOH is negative.
Question 2: A 3-year-old child has strawberry-red, sharply demarcated perianal erythema with satellite pustules. Culture grows Streptococcus pyogenes. What is the treatment?
- Oral penicillin for 10 days (Correct answer)
- Topical nystatin
- Topical hydrocortisone
- Systemic fluconazole
Correct answer: Oral penicillin for 10 days
Perianal streptococcal dermatitis caused by Group A Strep is treated with oral penicillin or amoxicillin for 10 days.
Question 3: A patient presents with multiple flesh-colored, dome-shaped papules with central umbilication on the trunk and arms. The patient is immunocompetent. What is the natural course without treatment?
- Self-resolution within 6-12 months (Correct answer)
- Progressive spread requiring systemic antiviral therapy
- Malignant transformation in 5% of cases
- Permanent scarring
Correct answer: Self-resolution within 6-12 months
Molluscum contagiosum in immunocompetent individuals is self-limiting and typically resolves spontaneously within 6-18 months without treatment.
Question 4: A 65-year-old man has a hyperkeratotic, scaly, erythematous plaque on the dorsum of the hand that has been present for 2 years. Biopsy shows full-thickness epidermal dysplasia. What is the diagnosis?
- Squamous cell carcinoma in situ (Bowen disease) (Correct answer)
- Actinic keratosis
- Basal cell carcinoma
- Merkel cell carcinoma
Correct answer: Squamous cell carcinoma in situ (Bowen disease)
Bowen disease (SCC in situ) shows full-thickness epidermal dysplasia on biopsy and presents as a persistent, slowly enlarging scaly plaque.
Question 5: A 55-year-old presents with a solitary, firm, brown-red papule on the leg that dimples inward when pinched laterally (positive dimple sign). What is the diagnosis?
- Dermatofibroma (Correct answer)
- Melanoma
- Blue nevus
- Kaposi sarcoma
Correct answer: Dermatofibroma
Dermatofibroma is characterized by the positive dimple sign (lateral compression causes central dimpling) and is a benign fibrous histiocytoma.
Question 6: An infant has vesicles and pustules on the scalp and trunk at birth. Tzanck smear shows multinucleated giant cells. The mother has a history of genital herpes. What is the immediate management?
- Intravenous acyclovir (Correct answer)
- Oral valacyclovir
- Topical acyclovir cream
- Watchful waiting with supportive care
Correct answer: Intravenous acyclovir
Neonatal herpes simplex infection is life-threatening and requires immediate intravenous acyclovir therapy regardless of disease extent.
Question 7: A 42-year-old woman presents with symmetric, well-demarcated hyperpigmentation on the cheeks, upper lip, and forehead exacerbated by sun exposure and oral contraceptive use. What is the diagnosis?
- Melasma (Correct answer)
- Addison disease
- Post-inflammatory hyperpigmentation
- Café-au-lait macules
Correct answer: Melasma
Melasma presents as symmetric facial hyperpigmentation triggered by UV exposure and hormonal factors such as oral contraceptives or pregnancy.
Family Practice Exam Dermatology 4
A 48-year-old woman presents with hypopigmented macules on the face and neck that do not tan in summer.
Wood's lamp examination shows enhanced pigmentation of surrounding normal skin.
KOH is negative.
What is the diagnosis?