Key points
- The most common symptoms of ehrlichiosis are fever, headache, and malaise, but symptoms vary from person-to-person.
- Most people will have a mild or moderate illness, though severe illness and death are possible.
- Blood tests such as complete blood cell count and a complete metabolic profile, can support the diagnosis.
Common signs and symptoms
- The most common symptoms of ehrlichiosis are fever, headache, and malaise, but symptoms vary from person-to-person.
- Most people will have a mild or moderate illness, though severe illness and death are possible.
- Signs and symptoms typically begin within 5–14 days after the bite of an infected tick. However, many people will not remember a tick bite.
- Common laboratory abnormalities include elevated aminotransferase levels, leukopenia, and thrombocytopenia.
Reminder
Clinical assessment
Early illness
Signs and symptoms commonly seen in the first few days of illness (days 1–5) include:
- Fever, chills, rigors
- Headache
- Malaise
- Myalgia
- Gastrointestinal symptoms (nausea, vomiting, diarrhea, anorexia)
- Confusion
- Rash
- Rash develops in up to 60% of children, but less than 30% of adults, and typically begins 5 days after symptom onset.
- The rash usually spares the face, but in some cases may spread to the palms of hands and soles of feet.
- The rash associated with E. chaffeensis infection may range from maculopapular to petechial in nature and is usually not pruritic (itchy).
- Rash develops in up to 60% of children, but less than 30% of adults, and typically begins 5 days after symptom onset.
Late illness
If treatment is delayed, the disease may become severe. Severe illness may involve:
- Meningitis, meningoencephalitis, and other central nervous system involvement (20% of patients)
- Acute respiratory distress syndrome
- Toxic shock-like or septic shock-like syndromes
- Renal failure
- Hepatic failure
- Coagulopathy
- Pancytopenia
Risk factors for severe disease:
- Delayed antibiotic treatment
- Age: Younger than 5 years old and older than 65 years old.
- Immune-compromising conditions, e.g., advanced HIV, persons receiving chemotherapy or other immune-suppressing medications
Clinical course
The clinical course varies from person to person depending on patient age, co-morbid conditions, immune status, and timing of treatment initiation relative to illness onset. Patients who are treated early may recover quickly with outpatient antibiotic treatment, while those who experience a more severe course might require hospitalization or intensive care.
Clinical features of E. ewingii and E. muris eauclairensis ehrlichiosis
Symptoms of E. ewingii and E. muris eauclairensis infections are similar to those of E. chaffeensis, although typically less severe. Gastrointestinal symptoms are less common in patients with E. ewingii ehrlichiosis and rash is infrequent in cases of E. muris eauclairensis.
Laboratory testing
Bloodwork
Healthcare providers should consider results from blood tests, such as a complete blood cell count and complete metabolic profile when making the diagnosis.
- Abnormal laboratory findings can include leukopenia, thrombocytopenia, and moderately elevated hepatic transaminases.
- Abnormal laboratory findings can appear in the first week of illness; however, normal laboratory findings do not rule out possible infection.
- Anemia is reported in about half of patients but generally occurs later in illness.