A 10-year-old boy who helps his father tend cattle develops a boggy, inflamed, pustular plaque on the scalp with associated cervical lymphadenopathy. Hair plucking shows large-spored ectothrix invasion. Which organism is the most likely cause?
- A Trichophyton verrucosum ✓
- B Microsporum audouinii
- C Trichophyton tonsurans
- D Trichophyton rubrum
Correct answer: A. Trichophyton verrucosum
Explanation
C kerion is an intensely inflammatory boggy plaque caused by zoophilic dermatophytes. Trichophyton verrucosum is acquired from cattle, produces large-spored ectothrix hair invasion and classically causes kerion in rural children. Trichophyton tonsurans is anthropophilic, causes endothrix invasion and typically produces a mild non-inflammatory seborrhoeic pattern. Microsporum audouinii is anthropophilic and fluoresces under Wood lamp, while Trichophyton rubrum is a cause of tinea corporis and onychomycosis rather than kerion.
Reference: Jagdish Chander, Textbook of Medical Mycology, 4th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.