Answer to Question 1
A
Small red papules with peripheral scaling in a sharply demarcated area involving the anterior thighs, lower abdomen, and perineum are characteristic of primary candidiasis. A shiny, parchment-like erythematous rash on the buttocks, medial thighs, mons pubis, and scrotum, but not in the folds, is suggestive of irritant contact dermatitis. Intertrigo is identified by a red macerated area of sharp demarcation in the groin folds. It can also develop in the gluteal and neck folds. Seborrheic dermatitis is recognized by salmon-colored, greasy lesions with a yellowish scale found primarily in skin-fold areas or on the scalp.
Answer to Question 2
B
Tretinoin causes photosensitivity and sunscreen should be applied before sun exposure. Tretinoin is a topical medication. Application is not affected by meals. If applied together, benzoyl peroxide and tretinoin have reduced effectiveness and a potentially irritant effect. Optimal results from tretinoin are not achieved for 3 to 5 months.