About Ehrlichiosis

Ehrlichiosis is a bacterial illness transmitted by ticks. Ehrlichiosis causes flu-like symptoms. Another tick-borne infection — anaplasmosis — is closely related to ehrlichiosis. But the two have distinct differences and are caused by different microorganisms.

The signs and symptoms of ehrlichiosis range from mild body aches to severe fever and usually appear within a week or two of a tick bite. If treated quickly with antibiotics, ehrlichiosis generally improves within a few days.

Ehrlichiosis is most common in spring and summer, when ticks are active and you’re more likely to be outdoors.

The best way to prevent Ehrlichiosis infections is to avoid tick bites. Tick repellents, thorough body checks after being outside and proper removal of ticks give you the best chance of avoiding ehrlichiosis.

Ehrlichiosis Causes

Ehrlichiosis is caused by Ehrlichia chaffeensis bacteria and is transmitted primarily by the Lone Star tick.

Ticks feed on blood, latching onto a host and feeding until they’re swollen to many times their normal size. During feeding, ticks that carry disease-producing bacteria can transmit the bacteria to a healthy host. Or they may pick up bacteria themselves if the host is infected.

To get ehrlichiosis, you must be bitten by an infected tick. The Ehrlichiosis bacteria enter your skin through the bite and eventually make their way into your bloodstream. Before bacteria can be transmitted, a tick must be attached and feeding for at least 24 hours. An attached tick that has a swollen appearance may indicate that enough time has elapsed to transmit bacteria. Removing the tick as soon as possible may prevent infection.


If a tick infected with ehrlichia or anaplasma bites you, the following flu-like signs and symptoms may appear within five to 14 days of the bite:

  • Mild fever
  • Headache
  • Muscle aches
  • Nausea
  • Vomiting
  • Diarrhea
  • Cough
  • Joint pain
  • Confusion
  • Rash — rare in adults, but more frequent in children

Some people infected with ehrlichiosis may have symptoms so mild that they never seek medical attention, and the body fights off the illness on its own. But untreated ehrlichiosis with persistent symptoms can result in an illness serious enough for hospitalization.

Ehrlichiosis Diagnosis

Tick-borne infections are difficult to diagnose based solely on symptoms because the symptoms are similar to many other common causes of fever or body aches.

A pattern of abnormal blood tests may lead your doctor to a diagnosis. Your doctor may prescribe antibiotics after analyzing your symptoms and may have you undergo a specific diagnostic blood test. If the symptoms don’t subside with your doctor’s recommendations, see your doctor for a follow-up visit.

Ehrlichiosis Treatment

If it’s suspected that you have ehrlichiosis, your doctor will likely give you a prescription for an antibiotic such as tetracycline or doxycycline. You’ll generally take the antibiotics for seven to 10 days and should see the signs and symptoms subside. Your doctor may have you take antibiotics for a longer period if you’re at risk of contracting Lyme disease as well.

Prevention ehrlichiosis infection

The best way to steer clear of ehrlichiosis is to avoid tick bites.

Most ticks attach themselves to your lower legs and feet as you walk or work in grassy, wooded areas or overgrown fields. After a tick attaches to your body, it usually crawls upward to find a location to burrow into your skin. Common tick bite locations include the back of your knees, groin, underarms, ears and back of your neck.

If you remove a tick in the first 24 hours after attachment, you greatly reduce your risk of infection. While you may not be able to avoid going into areas where ticks are present, the following tips can make it easier to discover and remove ticks before they attach to your skin:

  • Wear light-colored clothing. Ticks are dark. Light clothing helps you and others notice ticks on your clothing before they can attach themselves to your skin.
  • Avoid open-toed shoes or sandals. Ticks generally live in grassy areas or fields and can attach themselves to your feet and legs when you brush by. Wearing open-toed shoes or sandals increases the risk of a tick attaching to your bare skin and working its way under your clothes, out of sight from detection.
  • Apply repellent. Products containing DEET (Off! Deep Woods, Repel) or permethrin (Repel Permanone) often repel ticks. DEET is very effective on your skin, but follow the concentration recommendations on the label and don’t apply DEET to your face. A repellent with DEET may not be a good idea for children because they’re more likely to get the repellent in their eyes.
  • Wear long pants and a long-sleeved shirt. The less skin you expose, the less area a tick has to bite. For added protection, wear shirts, pants and socks with permethrin impregnated in the fabric.
  • Tuck your shirt into your pants and your pants into your socks. By doing this, ticks will be less able to crawl onto exposed skin.
  • Stay on clear trails whenever possible. Ticks prefer grassy areas and may be less common on well-beaten paths.
  • Pull back long hair. Ticks may attach to dangling hair and work their way to your neck or scalp. Pulling back long hair helps you see ticks better on your neck and limits the chance of them attaching in the first place.
  • Inspect your body. Do a complete visual inspection of your body. Be sure to check your head and neck because ticks will continue to climb upward until they find a suitable burrowing site. Use your hands to feel through your hair and in areas you can’t see when you return from your outing or garden.

    Ticks can be as small as a strawberry seed, and they usually attach to hidden skin. Be sure to check all the possibilities. A shower alone will rarely dislodge attached ticks from your head and body.

  • Inspect your clothes. Ticks may have hitched a ride on your clothes. Check your clothes, too. You can spin them in your clothes dryer for 20 minutes to kill any ticks you might have missed.