A 22-year-old woman presents with ringworm; which over-the-counter medication would be most suitable?

• A. Terbinafine 1% cream
• B. Miconazole 2% cream
• C. Clotrimazole 1% cream
• D. Ketoconazole 2% cream

Answer: (C)

Ringworm is a superficial fungal infection of the skin caused by dermatophytes. For uncomplicated infections in a healthy person, a topical antifungal available over the counter is appropriate. Clotrimazole 1% cream works by inhibiting fungal sterol synthesis (lanosterol 14α-demethylase), which disrupts the fungal cell membrane and stops growth. This mechanism is effective against dermatophytes that cause ringworm, and clotrimazole is widely used, well tolerated, and has minimal systemic absorption, making it suitable for outpatient use. It’s best applied to the affected area (and a surrounding margin) twice daily for about two to four weeks, with continued use for a short period after symptoms improve to prevent relapse. If there’s no improvement within one to two weeks, or if the infection is extensive, involves the face, scalp, or nails, or the patient has conditions like diabetes or immune suppression, seek medical assessment.