36-13: Chromoblastomycosis (Chromomycosis)

Chromoblastomycosis is a chronic, principally tropical cutaneous infection usually affecting older male agricultural workers and caused by several species of closely related black molds; Cladophialophora carrionii and Fonsecaea pedrosoi are the most common etiologic agents.

Lesions usually follow implantation wounds and are slowly progressive, occurring most frequently on a lower extremity. The lesions begin as a papule or ulcer. Over months to years, papules enlarge to become vegetating, papillomatous, verrucous elevated nodules along with scarring. The lesions may vary in appearance and have been classified into five categories: (1) nodular, (2) verrucous or warty, (3) plaque (infiltrative or erythematous), (4) tumoral, or (5) atrophic. There may be secondary bacterial infection. Elephantiasis may result, as can squamous cell cancers.

The fungi appear as brown, thick-walled, spherical, sometimes septate cells in potassium hydroxide preparations of pus or skin scrapings (so-called Medlar bodies), which are quite sensitive for diagnosis, as are punch or excisional biopsy specimens.

Itraconazole, 200–400 mg/day orally for 6–18 months, achieves a response rate of 65% (Table 36–1). Terbinafine at 500–1000 mg/day orally may have similar efficacy to itraconazole and the two may be useful in combination, especially in difficult to treat cases. Posaconazole appears to have the most reliable in vitro activity, but clinical data are lacking. The combination of 5-fluorocytosine with one of the above drugs also has been shown to be active; however, patients require careful monitoring for adverse events, and the drug can be difficult and expensive to obtain in countries with limited resources. Surgery or photodynamic therapy combined with antifungal drugs has been used successfully, as have immunomodulatory drugs such as imiquimod.