Fatal rocky mountain spotted fever in a 2-year-old child

A 2-year-old boy developed an acute undifferentiated febrile disease that was considered clinically to be a nonspecific viral syndrome. Progressive deterioration with severe central nervous system involvement, cerebral edema, and brain stem herniation led to death 8 days after onset. Disseminated rickettsial infection of endothelium was accompanied by a lymphohistiocytic vasculitis that is usually the hallmark microscopic lesion recognized by the pathologist. The diagnosis was established by immunohistochemical demonstration of intraendothelial spotted fever group rickettsiae.