Tinea Pedis — SCE Dermatology MCQ

Correct answer: B — Obtain fungal microscopy and culture before considering systemic therapy or alternative diagnoses

Explanation lettering: E = shown as A · C = shown as B · A = shown as C · B = shown as E

C is correct. Treatment failure, unilateral hyperkeratosis and immunosuppression broaden the differential to include dermatophyte infection, psoriasis, dermatitis, keratoderma and less common infections. Mycological confirmation from an active scaly edge, together with examination of the nails, groin and hands, should precede prolonged systemic antifungal therapy when the diagnosis is uncertain. A exposes the patient to interactions and hepatic toxicity without confirmation. B may worsen occult tinea. D does not investigate dermatophytes. E is disproportionate without a focal suspicious lesion; biopsy can be considered if sampling is negative and the diagnosis remains unclear.

Reference: NHS athlete’s foot guidance: https://www.nhs.uk/conditions/athletes-foot/