Signs and Symptoms of Ehrlichiosis

Key points

  • Ehrlichiosis symptoms typically begin within 1-2 weeks after the bite of an infected tick.
  • Symptoms can include fever, chills, headache, muscle aches, nausea, and rash.
  • Delay of antibiotic treatment can sometimes result in severe illness.
Healthcare provider talking to patient

Signs and symptoms

Signs and symptoms of ehrlichiosis typically begin within 1-2 weeks after the bite of an infected tick.

  • Tick bites can be painless, and many people do not remember being bitten.

See your healthcare provider if you become ill after being bitten by a tick or spending time in grassy, brushy, wooded areas.

Early signs and symptoms

Early signs and symptoms (the first 5 days of illness) are usually mild or moderate and may include:

  • Fever
  • Chills
  • Severe headache
  • Muscle aches
  • Nausea, vomiting, diarrhea, loss of appetite
  • Confusion
  • Rash (more common in children)


Up to 1 in 3 people with ehrlichiosis report a rash; rash is more common in people with E. chaffeensis ehrlichiosis and generally occurs more often in children than adults. Rash usually develops 5 days after fever begins. If a person develops a rash, it can look like red splotches or pinpoint dots.

Later symptoms

If antibiotic treatment is delayed, ehrlichiosis can sometimes cause severe illness. Early treatment can reduce your risk of developing severe illness.

Signs and symptoms of severe (late stage) illness can include:

  • Damage to the brain or nervous system (e.g. inflammation of the brain and surrounding tissue (called meningoencephalitis)
  • Respiratory failure
  • Uncontrolled bleeding
  • Organ failure
  • Death

Risk factors for severe illness:

  • Delayed antibiotic treatment
  • Age: younger than 5 years old or older than 65 years old
  • Weakened immune system: such as those receiving some cancer treatments, individuals with advanced HIV infection, people who have received organ transplants, or people taking certain medications
A father takes the temperature of a small child lying on a couch.
A fever can be an early symptom of ehrlichiosis.