What to Know About Ehrlichiosis

Medically Reviewed by Jabeen Begum, MD on November 11, 2021
3 min read

Ehrlichiosis is an infection spread by ticks that carry the ehrlichia bacterium. There are many species of tick in the U.S., but the lone star tick, found mainly in the central and southeastern states, is the primary transmitter of ehrlichiosis.

In 2019, just over 2,000 cases of ehrlichiosis were reported in the U.S. The fatality rate ranges from 1%-3%.

If you are infected by a tick bite and do not get treatment, however, you may suffer long-term health complications. 

You are at a higher risk of being bitten if you live in a place that has disease-carrying ticks. These ticks are found in the southeastern and central United States. Some cases have also been reported in Minnesota and Wisconsin. 

The ticks that carry the ehrlichia bacteria cause a group of infections collectively known as ehrlichiosis. When these ticks bite, they transfer other types of infections, as well. These include Lyme disease and Rocky Mountain spotted fever. 

Various types of ticks carry the bacterium, but the lone star tick is responsible for most cases reported in the U.S.

In some cases, ehrlichiosis is also caused due to bacterium-infected blood transfusions or organ transplants.

Ehrlichiosis symptoms may vary from mild to life-threatening, and typically show up 1-2 weeks after the tick bite. You may have some or all. The most common ones are:

  • Severe headache
  • Fever 
  • Muscle aches
  • Joint pain
  • Nausea or vomiting
  • Diarrhea
  • Chills
  • Cough
  • Fatigue
  • Red eyes
  • Rash 

People with other health conditions have a higher chance of having severe symptoms. 

Your doctor will take your medical history and do a physical exam. They might order blood tests to confirm the presence of the Ehrlichia bacterium.

The doctor may also examine your  white blood cells under a microscope to see if the bacteria is inside them.

Other information about blood counts and liver tests also help in the diagnosis of ehrlichiosis.

Ehrlichiosis is usually treated with doxycycline, an antibiotic. This antibiotic works for both children and adults. 

In most cases, the fever goes away within 24-48 hours of taking doxycycline, but you will continue with the full course of the antibiotic as directed by your doctor.

In severe cases, doctors may recommend intravenous (IV) antibiotics until the ehrlichiosis symptoms improve.

Ehrlichiosis can lead to severe complications in people with weak immune systems. The immune system can weaken due to HIV or cancers. Healthy people who don’t get medical attention early can also face health complications that include:

  • Neurological problems, like nervousness, seizures, or coma
  • Septic shock
  • Hemorrhage, excessive bleeding 
  • Kidney failure
  • Heart failure
  • Respiratory issues, breathing failure

In some cases, you may require additional treatment, including kidney dialysis or breathing support.

Avoiding places where ticks are is the best way to prevent ehrlichiosis. Other measures you can take include:

  • Spray your outdoor clothing, shoes, tent or other camping gear with a repellent that has 0.5% permethrin. 
  • Use an insect repellent registered with the Environmental Protection Agency on any exposed skin, except your face. These include repellents that contain DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD) or 2-undecanone.
  • Wear light-colored clothing that makes it easier for you or others to see ticks on your clothing before they bite.
  • Avoid open-toed shoes or sandals.
  • Wear long-sleeved shirts tucked into your pants and long pants tucked into your socks.
  • Shower as soon as possible to wash off any loose ticks and check for ticks that may have burrowed.
  • Use a mirror to check your body thoroughly. Pay attention to your underarms, hair and hairline, ears, waist, between your legs, behind your knees, and inside your belly button.
  • Remove ticks on your skin as soon as you see them. With tweezers, grasp the tick as close to your skin as possible. Pull gently and steadily.
  • Be patient. Ticks can "cement" to your skin. 
  • Save the tick for identification, if possible. Wash the bite with soap and water.  
  • Don't try to burn a tick with a lit match or use other products (like petroleum jelly) on the tick. 

Most ticks don't carry the ehrlichia bacteria that causes the infection, so if you find a tick attached to your body, don't rush to the emergency room immediately. Instead, wait for a few days and observe if your body is showing any symptoms. 

Ehrlichiosis symptoms start appearing within one to two weeks after the bite. If you observe any such symptoms, see your doctor right away.