A 10-year-old child has painful, thick, yellow nails with onycholysis and a persistent brownish discolouration, along with scaly interdigital maceration and annular scaling on the foot soles. KOH preparation shows hyphae. What is the most common causative organism and appropriate treatment?

• A Candida albicans — oral fluconazole
• B Trichophyton rubrum — oral terbinafine ✓
• C Trichophyton verrucosum — griseofulvin
• D Epidermophyton floccosum — topical clotrimazole only

Explanation

Tinea pedis (athlete's foot) with onychomycosis (tinea unguium) in children is most commonly caused by Trichophyton rubrum, a dermatophyte that infects skin and nails. Nail involvement requires systemic antifungal therapy because topical agents cannot adequately penetrate the nail plate; oral terbinafine (fungicidal against dermatophytes) is first-line for onychomycosis. Candida albicans causes paronychia and white superficial onychomycosis but not the dry-type interdigital involvement described. T. verrucosum causes tinea capitis in cattle-exposed individuals. Topical clotrimazole alone is insufficient for onychomycosis.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.