[Generalized Mycobacterium avium-intracellulare infection due to immunosuppressive therapy of paraneoplastic dermatomyositis].

The ubiquitous Mycobacterium avium-intracellulare (MAI) is the most frequent cause of disseminated atypical mycobacteriosis in AIDS patients. MAI infections may develop in patients with other acquired immune defects, such as connective tissue disorders. In adults, the gastrointestinal and respiratory systems are most frequently affected. We report a patient with dermatomyositis receiving immunosuppressive therapy in whom only the skin and the skeletal system were affected by MAI. Because it presented with polymyositis-like symptoms, the infection was initially not identified and treated. The MAI was cultured from a periarticular joint effusion from the right upper arm and from venous blood, as well as identified histologically in lesional skin. Resistance to antibiotics developed most likely because the patient failed to take oral antibiotics regularly. Because of an acute exacerbation of the tumor-associated dermatomyositis, immunosuppressive therapy was initiated, while the tuberculostatic therapy was continued. Using these therapies both diseases markedly improved. In patients with connective tissue disorders receiving longterm immunosuppressive therapy, especially when changes in symptoms and signs are observed, opportunistic infections such as MAI should be considered and included in the differential diagnosis.