Simultaneous infection with Borrelia burgdorferi and human granulocytic ehrlichiosis.

A 5-year-old child with simultaneous early Lyme disease and human granulocytic ehrlichiosis (HGE) is described. Because of the shared vector, HGE and Lyme disease are increasingly identified as coinfections in tick-exposed patients. Early recognition of concurrent Lyme disease and HGE is important because amoxicillin, an antibiotic of choice for young children with early Lyme disease, is ineffective for HGE.