A history of participating in activities placing the patient at risk for a tick bite should be sought. Fever Fever is nearly universally present. Other Stiff neck, nausea and vomiting, abdominal pain, diarrhea, and sore throat all have been reported in a minority of patients. One series of patients with suspected Colorado tick fever and symptoms of abdominal pain, rash, or sore throat were found more likely to not have Colorado tick fever based on serologic diagnosis. Rash It is described as macular, maculopapular, and petechial.
Distribution is often truncal, in contrast to the more acral rash of Rocky Mountain spotted fever.
Rash tends to be short-lived, which is another point of differential value with Rocky Mountain spotted fever. Petechiae are associated with rare cases, complicated by thrombocytopenia. People who are exposed to the vector, D andersoni , in the endemic area of the mountainous areas in western North America are at risk. Laboratory studies generally are not helpful. Leukopenia may suggest the diagnosis.