[Eruptive melanocytic nevi during azathioprine therapy in myasthenia gravis]

While being treated with azathioprine and dexamethasone, a 21-year old man with myasthenia gravis suddenly developed rapidly progressing brown macules, predominantly on the trunk, palms and soles. We made a diagnosis of eruptive melanocytic nevi (EMN). This rare entity can appear after blistering skin diseases, in immunocompromised patients, and, in particular, during immunosuppressive therapy for autoimmune diseases. Since therapeutic regimens including azathioprine have been frequently reported in association with EMN, we recommended to our patient a treatment switch to mycophenolic acid to prevent the development of more nevi.