Rocky Mountain Spotted Fever

Rickettsia rickettsii is transmitted to humans by a tick bite. This boy had been camping a short time before a fever and the classic rash of Rocky Mountain spotted fever developed. The erythematous macular rash first appears on wrists and ankles and spreads to the trunk. Note the puffy appearance of the skin resulting from vasculitis.

(Case and photograph courtesy of W. B. Wadlington, MD.)