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Winter 2014, Vol. 22 No. 4

Hong Kong J. Dermatol. Venereol. (2014) 22, 210

The differential diagnosis includes infective causes (mycobacterial infection, chromoblastomycosis), malignant causes (Bowen's disease, squamous cell carcinoma)and inflammatory causes (lichen simplex chronicus).
There is an extensive suppurative granulomatous inflammation with abundant epitheloid histiocytes, lymphoid cells, neutrophils, plasma cells and occasional multinucleated giant cells in the papillary dermis. Dark brown, thick-walled, ovoid or spherical spores are noted. They lie singly or in small groups within the giant cells or freely in the tissue.
The diagnosis is chromoblastomycosis.
Multiple treatment modaIities are often combined as chromoblastomycosis is one of the most resistant deep mycotic infections known. Itraconazole is regarded as the best choice of therapy, but efficacy is not as high as one would desire. Severe cases may need to be treated for several years. A daily dose ranging from 200 mg to 400 mg has been used. A few studies have reported successful treatment of chromoblastomycosis with a combination of itraconazole and 5-flucytosine. Terbinafine can also be used but with a suboptimal result. Heat therapy is another treatment option. Thermotherapy may exert a direct toxic effect on the fungi and heat may induce or enhance the anti-infective immune response. In Japan, successful treatment of chromoblastomycosis has been reported with the use of pocket warmers. Cryotherapy, surgical excision and photodynamic therapy are also beneficial.