Therapeutic approaches to subcutaneous mycoses

Subcutaneous mycoses, which are much less common than superficial fungal infections, are characterized by a heterogeneous group of infections that often result from direct penetration of the fungus into the dermis and subcutaneous tissue through traumatic injury. The fungus spreads by local deep tissue invasion from the inoculation site. The disease usually remains localized and then slowly spreads to adjacent tissue and eventually to the lymphatics. More rarely, hematogenous dissemination is observed. There are usually various clinical features and thus a broad range of differential diagnoses. The common subcutaneous mycoses are sporotrichosis, chromoblastomycosis, phaeohyphomycosis, eumycotic mycetoma, and hyalohyphomycosis. Many subcutaneous mycoses are confined to the tropical and subtropical regions, but some, such as sporotrichosis, are also prevalent in temperate regions. Subcutaneous mycoses can occur in healthy individuals. In immuno-compromised individuals, these infections can disseminate widely. Treatment usually involves use of antifungal agents and/or surgical excision. Treatment of some serious subcutaneous mycoses remains unresolved, and there have been reports of relapses or progression during therapy and problems with lack of tolerability of antifungal drugs. Identification of the etiologic agent by culture is essential for prognostic and management considerations, since some fungi are more frequently associated with dissemination. Results of antifungal susceptibility tests may provide valuable information for deciding the appropriate method of treatment. Development of new antifungal agents and combination therapies may result in improvement in the management of subcutaneous mycoses in the future.