Family Practice Exam Dermatology 2 — Questions and Answers
Question 1: A 45-year-old presents with salmon-colored plaques with silvery scales on the elbows and knees. Nail pitting is also noted. What is the most likely diagnosis?
- Psoriasis vulgaris (Correct answer)
- Seborrheic dermatitis
- Lichen planus
- Pityriasis rosea
Correct answer: Psoriasis vulgaris
Psoriasis vulgaris presents with well-demarcated salmon-pink plaques with silvery scales on extensor surfaces, and nail pitting is a classic associated finding.
Question 2: A 28-year-old woman has recurrent facial flushing, erythema of the cheeks and nose, and papulopustules without comedones. What is the first-line topical treatment?
- Metronidazole gel (Correct answer)
- Benzoyl peroxide
- Tretinoin cream
- Salicylic acid wash
Correct answer: Metronidazole gel
Topical metronidazole is first-line therapy for rosacea, reducing papulopustules and erythema.
Question 3: A child presents with honey-crusted lesions around the mouth and nose that began as vesicles. Gram stain shows gram-positive cocci in chains. What organism is most likely responsible?
- Streptococcus pyogenes (Correct answer)
- Staphylococcus aureus
- Streptococcus pneumoniae
- Corynebacterium diphtheriae
Correct answer: Streptococcus pyogenes
Non-bullous impetigo is most commonly caused by Streptococcus pyogenes (Group A Strep), producing honey-colored crusts.
Question 4: A 60-year-old man presents with a pearly, rolled-border nodule with telangiectasias on the nose that has grown slowly over two years. What is the most likely diagnosis?
- Basal cell carcinoma (Correct answer)
- Squamous cell carcinoma
- Melanoma
- Sebaceous cyst
Correct answer: Basal cell carcinoma
Basal cell carcinoma classically appears as a pearly papule or nodule with rolled borders and telangiectasias, most often on sun-exposed areas like the nose.
Question 5: A 35-year-old develops pruritic, coin-shaped eczematous plaques on the lower legs in winter. What is the most likely diagnosis?
- Nummular eczema (Correct answer)
- Tinea corporis
- Psoriasis
- Contact dermatitis
Correct answer: Nummular eczema
Nummular (discoid) eczema presents as coin-shaped, pruritic, eczematous plaques often worse in dry winter conditions.
Question 6: A patient with HIV presents with violaceous papules and plaques on the skin and oral mucosa. Biopsy shows spindle cell proliferation. What is the diagnosis?
- Kaposi sarcoma (Correct answer)
- Bacillary angiomatosis
- Lymphoma cutis
- Secondary syphilis
Correct answer: Kaposi sarcoma
Kaposi sarcoma in HIV patients presents as violaceous lesions on skin and mucosa; biopsy shows spindle cell proliferation with vascular channels and is associated with HHV-8.
Question 7: A 50-year-old presents with a pigmented lesion with asymmetry, border irregularity, multiple colors (black, brown, red), and a diameter of 8 mm. What is the next best step?
- Excisional biopsy with 1-2 mm margins (Correct answer)
- Shave biopsy
- Punch biopsy of darkest area only
- Topical imiquimod and watchful waiting
Correct answer: Excisional biopsy with 1-2 mm margins
Excisional biopsy with narrow margins is the preferred approach for lesions suspicious for melanoma to allow complete pathologic evaluation.
Family Practice Exam Dermatology 2
A 45-year-old presents with salmon-colored plaques with silvery scales on the elbows and knees.
Nail pitting is also noted.
What is the most likely diagnosis?