Human monocytotropic ehrlichiosis

Human monocytotropic ehrlichiosis

Human monocytic ehrlichiosis
Classification and external resources
Ehrlichia chaffeensis
ICD-9 082.41
DiseasesDB 31131
MedlinePlus 001381
eMedicine med/3391
MeSH D016873

Human monocytotropic ehrlichiosis[1] (HME) is a form of ehrlichiosis associated with Ehrlichia chaffeensis.[2]

This bacteria is an obligate intracellular pathogen affecting monocytes and macrophages.

Ecology & Epidemiology

In the USA, HME occurs across the south-central, southeastern, and mid-Atlantic states, regions where both the white-tailed deer (Odocoileus virginianus) and lone star ticks (Amblyomma americanum) thrive.

HME occurs in California in Ixodes pacificus ticks and in Dermacentor variabilis ticks.[3]

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.[4]


The most common symptoms are fever, headache, malaise, and muscle aches (myalgia). Compared to human granulocytic ehrlichiosis, rash is more common.[5] Laboratory abnormalities include thrombocytopenia, leukopenia, and elevated liver tests.

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.[6]


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.

Ehrlichia serologies can be negative in the acute period. PCR 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.

Presentation during early pregnancy can complicate treatment.[9]

Rifampin has been used in pregnancy and in patients allergic to doxycycline.[10]


  1. ^ Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology. Mosby. p. 1130.  
  2. ^ Schutze GE, Buckingham SC, Marshall GS, et al. (June 2007). "Human monocytic ehrlichiosis in children". Pediatr. Infect. Dis. J. 26 (6): 475–9.  
  3. ^ Holden K, Boothby JT, Anand S, Massung RF (July 2003). "Detection of  
  4. ^ "Statistics and Epidemiology: Annual Cases of Ehrlichiosis in the United States". Ehrlichiosis. Division of Vector-Borne Diseases (DVBD), National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Centers for Disease Control and Prevention. 5 September 2013. 
  5. ^ Dumler JS, Choi KS, Garcia-Garcia JC, et al. (December 2005). "Anaplasma phagocytophilum"Human granulocytic anaplasmosis and . Emerging Infectious Diseases 11 (12): 1828–34.  
  6. ^ Paddock CD, Folk SM, Shore GM, et al. (November 2001). "Infections with Ehrlichia chaffeensis and Ehrlichia ewingii in persons coinfected with human immunodeficiency virus". Clinical Infectious Diseases 33 (9): 1586–94.  
  7. ^ Prince LK, Shah AA, Martinez LJ, Moran KA (August 2007). "Ehrlichiosis: making the diagnosis in the acute setting". Southern Medical Journal 100 (8): 825–8.  
  8. ^ Hamburg BJ, Storch GA, Micek ST, Kollef MH (March 2008). "The importance of early treatment with doxycycline in human ehrlichiosis". Medicine 87 (2): 53–60.  
  9. ^ Muffly T, McCormick TC, Cook C, Wall J (2008). "Human granulocytic ehrlichiosis complicating early pregnancy". Infect Dis Obstet Gynecol 2008: 359172.  
  10. ^ Krause PJ, Corrow CL, Bakken JS (September 2003). "Successful treatment of human granulocytic ehrlichiosis in children using rifampin". Pediatrics 112 (3 Pt 1): e252–3.  

See also