A 6-year-old presents with an expanding annular erythematous plaque with central clearing on the thigh after a camping trip. The outer border is advancing with scales. KOH preparation shows branching septate hyphae. The child's scalp is unaffected. Which dermatophyte species is MOST commonly responsible for this presentation?
- A Trichophyton tonsurans — the most common cause of tinea corporis in children
- B Trichophyton rubrum — the most common cause of tinea corporis worldwide ✓
- C Microsporum canis — tinea corporis from animal contact
- D Epidermophyton floccosum — body ringworm in immunocompetent children
Correct answer: B. Trichophyton rubrum — the most common cause of tinea corporis worldwide
Explanation
Tinea corporis (ringworm of the body) presents as an expanding annular plaque with scaly, erythematous advancing edge and central clearing. Trichophyton rubrum is the most common cause of tinea corporis worldwide in children and adults (zoophilic T. mentagrophytes and M. canis are common in those with animal exposure). T. tonsurans is predominantly a cause of tinea capitis (scalp ringworm) in children in India and USA. E. floccosum causes tinea cruris predominantly. Treatment is topical azole or terbinafine for uncomplicated tinea corporis.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.