Which organism is the most common causative agent of tinea pedis in India?

Explanation

## Tinea Pedis: Epidemiology and Causative Organisms **Key Point:** *Trichophyton rubrum* is the most common causative agent of tinea pedis globally, including in India. It accounts for approximately 60–70% of all tinea pedis cases. ### Ranking of Causative Organisms in Tinea Pedis | Organism | Frequency | Clinical Features | |----------|-----------|-------------------| | **T. rubrum** | **60–70%** (most common) | Chronic, indolent; interdigital or moccasin type | | T. mentagrophytes | 20–30% | Acute, inflammatory; vesiculobullous or interdigital | | E. floccosum | 5–10% | Interdigital, mild inflammation | | M. canis | <1% | Rare; usually from animal contact | **High-Yield:** T. rubrum is the most common dermatophyte overall in India and causes the majority of tinea pedis, tinea corporis, and tinea cruris cases. ### Clinical Significance 1. **T. rubrum** — Chronic, slowly progressive; often affects the plantar surface (moccasin type); responds well to topical azoles but may require systemic therapy for severe cases. 2. **T. mentagrophytes** — More inflammatory; causes acute blistering and pustulation; responds faster to treatment but has higher relapse rates. 3. **E. floccosum** — Mild, localized; usually interdigital; rare in India. 4. **M. canis** — Zoophilic; rare; associated with animal exposure. **Mnemonic:** **TERM** — *Trichophyton rubrum* is the **E**ssential/most common organism in tinea pedis (and most tinea infections in India). **Clinical Pearl:** When tinea pedis is suspected in an Indian patient, T. rubrum should be the presumed organism until KOH mount or culture proves otherwise.