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chromoblastomycosis (chromomycosis)
Etiology:
- traumatic inoculation of pigmented fungi through the skin, including:
- Fonsecaea pedrosoi
- Phialophora verrucosa
- Cladosporium carrionii
- Fonsecaea compacta
- Exophiala species
- Fonsecaea nubica
- Rhinocladiella aquaspersa
Epidemiology:
- rural populations in tropical or subtropical climates, Madagascar, Brazil, others
- lattitude between 30 degrees North & 30 degrees South
- male predominance (largely a result of differential risk of traumatic inoculation)
- most commonly occurs in men age 30-50 years
- the period between inoculation & disease manifestation is thought to be years, explaining the scarcity of children with chromoblastomycosis
Pathology:
- chronic infection involving the skin & subcutaneous tissue
- fungi induce a purulent & granulomatous inflammatory reaction in skin & subcutaneous tissue
- lymphatic & cutaneous dissemination can occur
Clinical manifestations:
- a nodule develops slowly at the site of innoculation
- over years, the nodule grows centripetally
- the central parts of the nodule may heal, leaving ivory-colored scars
- spread to neighboring healthy skin, forming plaques is common
- can involve an entire limb
- when nodules predominate over plaques, the affected region may have a cauliflower appearance
Laboratory:
- KOH preparation shows sclerotic cells (Medlar bodies)
- globe-shaped
- cigar-colored
- thick-walled structures 4-12 um in diameter
- these are the pathogenic organism
Complications:
- mortality is rare
Management:
- refractory to treatment
- itraconazole is drug of choice
- 200-400 mg PO QD of variable benefit
- severe cases may require years of treatment
- flucytosine (Ancobon) may be synergistic with itraconazole (not for monotherapy)
- cure rarely achieved
- terbinafine has been used
- posaconazole (Noxafil) has been used experimentally
- heat therapy may be of benefit (heat apparently inhibits fungus)
- cryotherapy with liquid nitrogen
- multiple cycles may be needed
General
mycosis; fungal infection
References
- Schwartz RA and Baran E
eMedicine: Chromoblastomycosis
http://emedicine.medscape.com/article/1092695-overview