Ehrlichiosis--"spotless spotted fever".

Ehrlichia Canis, a canine rickettsia, produces an acute infection in humans characterized by thrombocytopenia, leukopenia, and anemia. Patients should be closely questioned and examined for tick bites. Rash is not prominent, leading to the interesting if somewhat inaccurate label of "spotless spotted fever." The diagnosis is made by clinical presentation, absence of positive Lyme disease or Rocky Mounted Spotted Fever (RMSF) serology, and positive E. canis titers. Tetracyclines are preferred treatment. Ehrlichiosis should be considered in the differential diagnosis of fevers of unknown origin, Lyme disease, idiopathic thrombocytopenia, and hypoplastic anemia.