Ehrlichiosis Clinical Presentation
- Author: Burke A Cunha, MD; Chief Editor: Michael Stuart Bronze, MD more...
History
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% in 1 series)
- Fevers (>90%)
- Headaches (>85%)
- Malaise (>70%)
- Myalgias (>70%)
- Rigors (60%)
- Nausea (40%)
- Vomiting (40%)
- Anorexia (40%)
- Confusion (20%)
Rash is rare in patients with HME/HGA. Rash is rare but, if present, usually occurs on the trunk, legs, arms, or face and may be macular, maculopapular, and/or petechial. Rash on the palms or the soles is very rare.
Physical Examination
Physical findings due to ehrlichiosis are minimal.
Splenomegaly is not uncommon, and some patients develop hepatomegaly. Lymphadenopathy is very uncommon. Patients with severe ehrlichiosis may develop thrombocytopenia or disseminated intravascular coagulation (DIC), which can result in purpura.
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| Human monocytic ehrlichiosis (HME) | Human granulocytic anaplasmosis (HGA) | |
| Cell type Affected | Monocytes | Granulocytes |
| Organism | E chaffeensis | A phagocytophilum |
| Vector | Amblyomma americanum (Lone Star tick) | Ixodes scapularis (black-legged tick), Ixodes pacificus (Western black-legged tick) in California, Ixodes ricinus in Europe, and probably Ixodes persulcatus in parts of Asia |
| Location | Southeastern and south-central United States | Wisconsin and Minnesota, less active in New York and Connecticut, also California |
| Rash | 30% of adults, 60% of children | Rare |
| Prognosis | ~3% mortality | < 1% mortality |

