Ehrlichiosis

Ehrlichiosis is a potentially serious illness you get through the bite of an infected tick. Ehrlichia bacteria cause it.

Symptoms can start out mild and flu-like. But if not treated quickly, ehrlichiosis (“err-lik-ee-OH-sis”) can be life-threatening. Ehrlichiosis is sometimes called human monocytic ehrlichiosis (HME).

Symptoms of ehrlichiosis

Symptoms start five to 14 days after a tick bites you. They include:

• Fever
• Chills
• Headache
• Muscle pain or soreness
• Tiredness
• Cough
• Nausea and vomiting
• Stomach pain
• Confusion
• Rash

You might start off with a few symptoms and develop more over a few days. The rash is more common in kids than in adults. It can be splotchy, red patches or pinpoint dots.

Ehrlichiosis causes

Three types of Ehrlichia bacteria cause ehrlichiosis: E. chaffeensis, E. ewingii and E. muris eauclairensis. Symptoms of all three are similar, but E. chaffeensis is most likely to cause serious illness. You get infected with Ehrlichia when a tick bites an infected animal and then bites you.

How does it spread?

Ehrlichiosis spreads from animals to humans through tick bites. The most common carriers are the lone star tick and the blacklegged (deer) tick. Ticks bite infected animals, like deer, dogs or coyotes. The bacteria stay in the tick until it takes its next meal. When it bites you, the bacteria spread to your body.

In rare cases, you can get ehrlichiosis from a blood transfusion or organ transplant.

Risk factors

In the U.S., cases of ehrlichiosis happen mostly in Midwestern, Eastern and Southeastern states. It’s also found in other areas around the world.

You’re at a higher risk for getting severely ill with ehrlichiosis if you:

• Are older than 50 or younger than 5
• Have a compromised immune system (from HIV, cancer or medications)
• Have a chronic illness (like diabetes or connective tissue disorders)

Complications

If not treated quickly enough, some people with ehrlichiosis have serious or life-threatening complications, including:

• Disseminated intravascular coagulation (DIC)
• Acute respiratory distress syndrome (ARDS)
• Respiratory failure
• Renal failure (acute kidney injury)
• Internal bleeding (hemorrhaging)
• Sepsis
• Brain inflammation (meningoencephalitis)
• Heart failure
• Seizures
• Coma

How doctors diagnose ehrlichiosis

To diagnose ehrlichiosis, your healthcare provider will examine you and ask you about your symptoms and health history. It’s important to let them know if you’ve recently (within the past three weeks) been in an area where you could’ve been bitten by a tick, even if you don’t remember being bitten.

Your provider can use blood tests to confirm a diagnosis. They’ll take a sample of your blood from your arm with a small needle. A lab will look for signs of bacteria that cause ehrlichiosis. They’ll try to get bacteria to grow (culture).

Growing bacteria can take several weeks, so your provider will probably have to decide whether to treat you before the results are back. They can use blood counts (which come back quickly) to know whether you might have an infection.

How is it treated?

Ehrlichiosis is treated with antibiotics. You usually have to take them for about a week. Treatment is most effective if you start it soon after your symptoms appear. If you start treatment too late, ehrlichiosis can cause serious complications.

Recovery time

If you start antibiotics soon after symptoms appear, you should feel better within 24 to 48 hours. Continue taking antibiotics for as long as your healthcare provider prescribes, even after you feel better. If your symptoms don’t start improving within a few days, contact your provider.

When should I see my healthcare provider?

See a provider right away if you have symptoms of ehrlichiosis, especially if:

• You’ve been bitten by a tick recently
• You’ve been in an area where you could’ve gotten a tick bite (even if you don’t remember being bitten)

Keep an eye out for any symptoms if you get a tick bite. You don’t need to see your provider if you don’t have symptoms yet. Taking antibiotics when you’re not sick won’t help prevent ehrlichiosis.

When should I go to the ER?

Go to the nearest emergency room if you have any of these symptoms:

• Fever over 103 degrees Fahrenheit (39.4 degrees Celsius)
• Coughing up blood
• Severe shortness of breath
• Confusion or other mental changes
• Severe stomach (abdominal) pain
• Seizures

What’s the outlook (prognosis) for ehrlichiosis?

Nearly 60% (3 in 5) of people with ehrlichiosis are hospitalized. But the outlook is good if you get treated quickly. About 1% to 2% of cases are fatal.

Can this be prevented?

Avoiding tick bites is the best way to reduce your risk of ehrlichiosis. Strategies include:

• Keep grass cut shorter than 5 inches.
• Stay on cleared paths while in wooded areas.
• Use bug sprays with DEET or other ingredients approved to keep ticks away.
• Use clothing to cover as much of your skin as possible when you’re in the woods or areas with long grass. You can buy clothing treated with tick repellent if you’re often in areas with ticks.
• Check yourself for ticks after you’ve been outside. If possible, have someone else check you in places you can’t see yourself (like your back and scalp).
• Ask your veterinarian about the best way to protect your pets from ticks. Check your pets for ticks often, especially after they’ve been outside.
• Follow directions for safely removing a tick if you find one on you.