Chromoblastomycosis
A chronic, localized subcutaneous fungal infection caused by the traumatic implantation of dematiaceous (pigmented) fungi (e.g., Fonsecaea pedrosoi, Phialophora verrucosa).
Key Clinical Features
- Appearance: Slowly growing, verrucous (wart-like) or cauliflower-like plaques, often on lower extremities.
- “Black Dots”: Often seen on the surface of the lesions, representing transepidermal elimination of fungal elements.
- Course: Very slow progression over years; can lead to secondary bacterial infection or lymphedema.
Diagnostic & Management Pearls
| Aspect | Details |
|---|---|
| Histology | Pathognomonic “Medlar bodies” (sclerotic, copper-colored, septate yeast cells). |
| Treatment | Difficult; usually requires prolonged oral antifungals (Itraconazole or Terbinafine), sometimes combined with surgical excision or cryotherapy. |
High-Yield Exam Pearl:
- Medlar Bodies: Also known as “copper pennies” or “sclerotic bodies”—visualizing these under KOH or biopsy is the diagnostic key.
- Distribution: Most common in tropical and subtropical regions; usually affects rural agricultural workers who have frequent contact with soil/vegetation.