The severity of the illness can range from minor or asymptomatic to life-threatening. CNS involvement may occur. A serious septic or toxic shock-like picture can also develop, especially in patients with impaired immunity.[5]
Tick exposure is often overlooked. For patients living in high-prevalence areas who spend time outdoors, a high degree of clinical suspicion should be employed.[citation needed] Ehrlichia serologies can be negative in the acute period.Polymerase chain reaction is therefore the laboratory diagnostic tool of choice.[7]
If ehrlichiosis is suspected, treatment should not be delayed while waiting for a definitive laboratory confirmation, as prompt doxycycline therapy has been associated with improved outcomes.[8]Doxycycline is the treatment of choice.[citation needed]
Presentation during early pregnancy can complicate treatment.[9]Rifampin has been used in pregnancy and in patients allergic to doxycycline.[10]
In the US, human monocytotropic ehrlichiosis occurs across the south-central, southeastern, and mid-Atlantic states, regions where both thewhite-tailed deer (Odocoileus virginianus) and its ectoparasite, Lone Star ticks (Amblyomma americanum), thrive.[11][12][13]
Human monocytotropic ehrlichiosis occurs in California inIxodes pacificus ticks and inDermacentor variabilis ticks.[14] Nearly 600 cases were reported to the CDC in 2006. In 2001–2002, the incidence was highest in Missouri, Tennessee, and Oklahoma, as well as in people older than 60.[15]
