What caused this itchy, persistent rash?

An itchy rash on the dorsum of her dominant, right hand prompted a 34-year-old mother of three to try an over-the-counter miconazole and hydrocortisone preparation. The rash has not improved in 3 weeks. The patient washes her hands several times a day.

What is your next step?

A. Change her soap to one with a mild cream base.

B. Recommend that she apply moisturizer more frequently.

C. Prescribe a mid-potency topical corticosteroid.

D. Perform a potassium hydroxide (KOH) evaluation.

E. Perform a patch test for a possible allergic reaction.

(Answer on next page)

Answer: Dermatophyte infection

All of these strategies are appropriate, but it is essential to perform the KOH evaluation, D, first when red, itchy lesions suggest a dermatophyte. Here, the KOH preparation confirmed the diagnosis of a dermatophyte infection.

The patient had no exposure to pets, which can be a source of infection; however, frequent hand washing probably produced micro-cracks in the skin surface, which allowed the fungus to enter. The eruption responded to potent topical antifungal therapy, and it did not recur.