Which clinical history findings are characteristic of ehrlichiosis?

Updated: Jun 22, 2021
  • Author: Chinelo N Animalu, MD, MPH; Chief Editor: Michael Stuart Bronze, MD  more...
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Clinical manifestations of ehrlichiosis usually begin 5-14 days after the tick bite. Approximately 68% of patients with human monocytic ehrlichiosis (HME) report a tick bite, and 83% of patients have a history of tick exposure in the 4-week period before onset of symptoms. Onset is abrupt or subacute.

The histories for HME, human granulocytic anaplasmosis (HGA), and E ewingii infection are similar and may include the following [1, 2] :

  • Tick bites or exposure (>90%)
  • Fevers (>90%)
  • Headaches (>85%)
  • Malaise (>70%)
  • Myalgias (>70%)
  • Rigors (60%)
  • Nausea (40%)
  • Vomiting (40%)
  • Anorexia (40%)
  • Confusion (20%)

Skin rash is not considered a common feature of ehrlichiosis and should not be used to rule in or rule out an infection. E chaffeensis infection can cause rash in up to 60% of children, but rash is reported in fewer than 30% of adults. Rash is not commonly reported in patients infected with E ewingii or the E muris-like organism. [13]

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