Types

Understanding Ehrlichiosis

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When a tick bites you, it can cause an infection. Some types of ticks can pass on the bacteria that cause ehrlichiosis. This infection can turn into a serious illness. If you get a tick bite and then develop symptoms, talk with your doctor right away.


How to say it 

ayr-lik-ee-OH-sis


What causes ehrlichiosis?

The bacteria that cause ehrlichiosis are passed to people through tick bites. Ticks are most active between April and September. The risk of getting bitten and infected is higher during these warmer months. Ehrlichiosis may also be passed on through blood transfusions or by direct contact with an infected deer.


What are the symptoms of ehrlichiosis?

Symptoms often show up 1 to 2 weeks after you are bitten by a tick. They usually start suddenly. They may include:

  • Fever or chills.

  • Headache.

  • Muscle or joint pain.

  • Tiredness or feeling unwell.

  • Swollen lymph nodes.

  • Rash (more common in children).

  • Red eyes.

  • Nausea, vomiting, or diarrhea.

  • Confusion.

  • Cough.


How is ehrlichiosis diagnosed and treated?

Your doctor will use blood tests to diagnose ehrlichiosis.

Treatment focuses on killing the bacteria that cause ehrlichiosis. This is done by taking antibiotics. Doxycycline is the advised antibiotic for both adults and children. Other medicines may be given to help ease pain.


How can you prevent ehrlichiosis?

Not getting bitten by a tick is the best way to prevent ehrlichiosis. Here are some ways to stay away from ticks:

  • Put insect repellent containing DEET on exposed skin when you are outside. Use DEET with caution on young children.

  • Treat clothing and hiking or camping gear with products that have permethrin.

  • Don't walk through brush and grass.

  • Look for ticks on yourself after you have been outside. Check all parts of your body. Remove any ticks you find right away with fine-tipped tweezers.

  • If you have any pets, check them for ticks after they have been outside. Also check your gear, such as day packs and clothing.


What are the possible complications of ehrlichiosis?

Children and people who have a weak immune system are more likely than healthy adults to have complications. Complications of ehrlichiosis can include:

  • Trouble breathing.

  • Bleeding problems.

  • Liver or kidney failure.

  • Inflammation or infection of the brain or its covering.

  • Death.


When should you contact your doctor?

Contact your doctor or get medical care right away if you have:

  • A fever of 100.4°F (38°C) or higher, or as directed by your doctor.

  • Pain that gets worse.

  • Symptoms that don’t get better with treatment, or symptoms that get worse.

  • New symptoms.

Author: Freed, Becca

© 2000-2026 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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