Athlete's Foot (Tinea Pedis): Causes, Symptoms, and Treatment

"Aani rogam" (Tamil) = Athlete's foot (tinea pedis) – a common dermatophyte infection of the feet.

Etiology

• Dermatophytes: Trichophyton rubrum (70%), T. mentagrophytes, Epidermophyton floccosum.
• Risk factors: Occlusive footwear, hyperhidrosis, communal showers/pools, diabetes, immunodeficiency, age >60.

Clinical Types

• Interdigital (most common): Maceration, scaling, fissuring between 4th–5th toes. Pruritus.
• Moccasin (chronic hyperkeratotic): Diffuse scaling on soles/heels/lateral feet ("slipper" distribution). Often T. rubrum.
• Vesiculobullous: Tense vesicles/bullae on instep/soles. T. mentagrophytes. Intense itch.
• Ulcerative: Secondary bacterial infection (cellulitis). Diabetics/immunocompromised.

Diagnosis

KOH prep (hyphae), fungal culture (species ID), PCR. Wood's lamp: negative (dermatophytes don't fluoresce; Corynebacterium = erythrasma does).

Treatment

• Topical (1st line, 2–4 wks): Terbinafine 1% (fungicidal, shorter course), clotrimazole, miconazole, butenafine. Apply 1–2× daily 1–2 cm beyond lesion.
• Oral (extensive, moccasin, toenail involvement, topical failure): Terbinafine 250 mg/day × 2–6 wks (pulse for nails). Itraconazole, fluconazole alternatives. LFTs baseline.

Prevention

Dry feet thoroughly (esp. interdigital), moisture-wicking socks, rotate shoes, antifungal powder in shoes, avoid barefoot in communal areas, treat household contacts.