Abstract
Measles encephalitis rarely affects young adults and has no established treatment strategy. This brief report described the rare case of an immunocompetent 30-year-old man with severe measles pneumonia and encephalitis, following the autoimmune disease acute disseminated encephalomyelitis, during a large measles outbreak in 2018 in Japan. With multidisciplinary treatments, including corticosteroids, intravenous immunoglobulins, vitamin A, and therapeutic plasma exchange, the patient was successfully treated. This case provides a new strategy for treating measles encephalitis and its complications during measles outbreak.