Dermatologist Certificate Skin Disorders and Diagnosis 2 — Questions and Answers
Question 1: What is the most common cause of tinea capitis in the United States?
- Trichophyton tonsurans (Correct answer)
- Microsporum canis
- Trichophyton rubrum
- Epidermophyton floccosum
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 2: Dermatitis herpetiformis is strongly associated with which systemic condition?
- Celiac disease (gluten-sensitive enteropathy) (Correct answer)
- Crohn disease
- Systemic lupus erythematosus
- Inflammatory bowel disease
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 3: Which feature best distinguishes seborrheic keratosis from a melanoma?
- Stuck-on appearance with horn cysts visible on dermoscopy (Correct answer)
- Asymmetric borders and color variation
- Rapid growth over weeks
- Pruritus and bleeding
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 4: What is the ABCDE rule used to evaluate in dermatology?
- Asymmetry, Border irregularity, Color variation, Diameter >6mm, Evolution (Correct answer)
- Appearance, Bleeding, Crust, Diameter, Erythema
- Atopy, Barrier dysfunction, Contact allergy, Dryness, Erythema
- Age, Biopsy, Curettage, Dermoscopy, Excision
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 5: Which condition presents with comedones, papules, pustules, and nodules primarily on the face, chest, and back?
- Acne vulgaris (Correct answer)
- Rosacea
- Perioral dermatitis
- Folliculitis
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 6: What wood lamp finding is characteristic of erythrasma?
- Coral-red fluorescence (Correct answer)
- Blue-green fluorescence
- Yellow-green fluorescence
- No 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.
Dermatologist Certificate Skin Disorders and Diagnosis 2
What is the most common cause of tinea capitis in the United States?