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

More general terms

• mycosis; fungal infection