Health Dictionary Find a Doctor

Ehrlichiosis natural history, complications and prognosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Ilan Dock, B.S.

Overview

Overview

Early symptoms that are commonly associated with human granulocytotropic anaplasmosis (HGA) include sudden onset of fever and intense pains. Progression of the disease may lead to serious complications including neurological disorders and ARDS. Co-infection remains the greatest threat associated with death as a result of HGA. Human monocytotropic ehrlichiosis (HME) presents a very different scenario than that of HGA. HME is far more dangerous as well as deadly. An incubation period of 7-10 days will often follow an infected tick bite. Initial symptoms include fever, headache, and malaise. Further complications will follow the onset of infection, these complications may prove to be extremely dangerous and should be closely monitored for the patients safety. Unlike HME, the prognosis is usually good for human granulocytotropic anaplasmosis (HGA). Individuals suffering from HGA should fully recover without treatment in 2 months. However, proper treatment of HGA will expedite the recovery process.

Natural History

Natural History

Infection varies according to the Ehrlichiae agent responsible for the infection. Listed below are the progressive pathways of each infection:

Human granulocytotropic anaplasmosis

Early Stage

  • Sudden onset of fever with rigors
  • Severe Myalgia
  • Early Symptoms such as pain, nausea, vomiting, weight loss, cough, and confusion

Late Stage

If left untreated

  • Usually achieve a full recovery in 2 months
  • Immuno-compromised individuals may suffer severe infections or even death as a result of an opportunistic co-infection.

Human monocytotropic ehrlichiosis

Early Stage

  • Incubation of 7-10 days
  • Initial presenting symptoms include fever, headache, and malaise.
  • More severe infections will include myalgia, diaphoresis, weight loss, maculopapular rash, and confusion.

Late Stage

  • Progression of symptoms requires hospitalization
  • Majority of infected patients require intensive care
  • Even with medical therapy 2.7% of infected patients die

If left untreated

Complications

Complications

Common complications associated with an ehrlichiosis infection are listed below:

Prognosis

Prognosis

Human granulocytotropic anaplasmosis

  • The prognosis for HGE is usually good.
  • With proper treatment, patients should fully clear infection
  • About Half of infected individuals will require 6 days of hospitalization
  • Even in the absence of treatment, infected patients should clear infection within 2 months
  • Death associated with opportunistic co-infection.

Human monocytotropic ehrlichiosis

  • HME is a severe illness with many complications
  • Even in the presence of proper medical therapy, nearly 2.7% of infected patients will die
  • Infection must be closely monitored in order to reduce the amount of possible complications
References

References

  1. Thomas, Rachael J (1 August 2009). “Current management of human granulocytic anaplasmosis, human monocytic ehrlichiosis and ehrlichiosis”. Expert Review of Anti-infective Therapy. 7 (6): 709–722. doi:10.1586/eri.09.44. PMC 2739015. PMID 19681699. Unknown parameter |month= ignored (help); Unknown parameter |coauthors= ignored (help)

Looking for the patient version?

Back to the patient-friendly article

© 2026 MyEClinic – IFTM Institut für Telematik in der Medizin GmbH