Clinical patterns of cutaneous nontuberculous mycobacterial infections

Background Cutaneous nontuberculous mycobacterial infections result from external inoculation, spread of a deeper infection, or haematogenous spread of a disseminated infection. There are two species-specific infections (fish-tank or swimming-pool granuloma, due to Mycobacterium marinum, and Buruli ulcer, caused by M. ulcerans). Most infections, however, produce a nonspecific clinical picture. Objectives To define clinical patterns of cutaneous disease in nontuberculous mycobacterial infections. Methods Fifty-one patients with cutaneous nontuberculous mycobacterial infections were reviewed. Clinical and histopathological features of normal hosts and immunosuppressed patients were compared. Two subgroups of immunosuppressed patients were distinguished: patients with cutaneous infection and patients with a disseminated infection and cutaneous involvement. Results In immunosuppressed patients the number of lesions was significantly higher. Abscesses and ulceration were also more frequently observed. Different species were found in normal hosts and immunosuppressed patients. Several clinical patterns of cutaneous infection were defined: lymphocutaneous or sporotrichoid lesions; nonlymphocutaneous lesions at the site of trauma; folliculitis and furunculosis involving the lower extremities; disseminated lesions on the extremities in immunosuppressed patients. Two patterns were observed in patients with a disseminated infection: localized cutaneous lesions and disseminated cutaneous and mucosal lesions. Conclusions Cutaneous manifestations of nontuberculous mycobacterial infections may be classified according to criteria such as cutaneous lesions and immune status.