An Essential Guide to Ehrlichiosis

Deer in the forest

With warmer weather on the way, many seasonal tick-related diseases may become more prevalent.

One of these is a lesser-known illness called ehrlichiosis. It’s typically caused by infected lone star ticks and can be fatal if left untreated.

Understanding the signs of ehrlichiosis and knowing what to do if it develops is essential for taking care of your health.

In this article, we’ll discuss everything you should know about ehrlichiosis, including how to treat and prevent it to help you enjoy a tick-free summer.

What is Ehrlichiosis?

Ehrlichiosis is a bacterial illness caused by Ehrlichia chaffeensis that primarily affects the white blood cells. It’s normally transmitted by an infected lone star tick — also known as a deer tick.

This disease is typically found in southeastern and south-central regions of the United States — including Texas, Oklahoma, Ohio, and Florida — where lone star ticks are most prevalent.

Signs and symptoms of ehrlichiosis

Symptoms of ehrlichiosis generally develop within one to two weeks after infection and may include:

  • Fever and chills

  • Severe headaches

  • Muscle aches (myalgia)

  • Fatigue

  • Nausea, vomiting, and diarrhea

  • Joint pain and arthritis-like symptoms

As the disease progresses, additional symptoms can develop. These may include:

  • A rash, especially in children

  • Confusion and mental cloudiness (brain fog)

  • Respiratory distress, including breathing difficulties

  • Bleeding disorders

  • Renal failure

Keep in mind that infected ticks may carry more than one harmful bacteria and can transmit multiple pathogens to humans.

If you’ve recently been bitten by a tick or live in a tick-infested area, monitor yourself for symptoms of related illnesses, such as Lyme disease, babesiosis, and Rocky Mountain Spotted Fever.

What Causes Ehrlichiosis?

Tick bites

The most common way to contract ehrlichiosis is through a bite from an infected tick. Lone star ticks can become infected with the Ehrlichia bacteria when they feed on affected animals.

These animals often include whitetail deer, which makes individuals particularly vulnerable to ehrlichiosis during hunting season.

Once bitten, the bacteria can be transmitted from the tick to its human host. However, the tick typically has to be attached to the skin for at least 24 to 48 hours before bacteria can be transmitted.

If the tick is removed from the body before then, your chances of being infected are reduced.

Blood transfusion and organ transplant

Although extremely rare, ehrlichiosis can also be transmitted through infected blood or organs transplanted from bacteria carriers.

This mode of transmission poses a significant risk to public health because it can occur without the typical warning signs of a tick bite, making it harder to diagnose and treat.

Although screening processes for organ donors are rigorous, doctors may not always detect infections — especially if the disease is still in the incubation phase.

How is Ehrlichiosis Diagnosed?

Ehrlichiosis is diagnosed by a healthcare professional using a comprehensive approach to evaluate your symptoms.

This process usually begins with a medical history review and symptomatic evaluation.

Your doctor will likely ask you about potential tick exposure or tick bites, and they may also perform a physical exam to check for symptoms like a rash.

After the initial evaluation, your doctor will recommend a blood test to provide a more accurate diagnosis. These tests may involve:

  • Indirect immunofluorescent assay (IFA): An IFA is typically used to confirm an ehrlichiosis diagnosis, but it can take up to three weeks to perform. This is because blood samples are taken in the first week of symptom onset and then again 2 to 4 weeks later to confirm an infection.

  • Polymerase chain reaction (PCR) test: This test allows healthcare providers to identify specific bacterial components in the blood. A PCR test is usually most accurate in the first week of contracting the disease.

Depending on the results of these tests, your doctor will recommend an appropriate treatment method to help you overcome any infection.

However, ehrlichiosis may be difficult to diagnose due to the bacteria’s ability to change its genetic code, making it harder to detect.

That’s why it’s important to consult your doctor as soon as symptoms develop to ensure prompt testing and diagnosis.

How is Ehrlichiosis Treated?


The primary treatment option for ehrlichiosis is a course of antibiotics. Doxycycline is usually recommended because it’s been proven effective against Ehrlichia bacteria.

Treatment with doxycycline should start as soon as possible to ensure the best results.

A typical course can last between five to seven days, with an option to extend it if the ehrlichiosis infection is severe or if the individual had a delayed start to treatment.

Some people may be allergic to or unable to use doxycycline — including pregnant women and children under the age of eight.

In this case, a healthcare provider will recommend alternatives, such as rifampin.

Symptomatic management

Alongside antibiotic therapy, managing the symptoms of ehrlichiosis is essential — especially if you have a severe infection.

Symptomatic management may include:

  • Use over-the-counter (OTC) pain and fever medications, such as ibuprofen or acetaminophen

  • Ensuring that you replace fluids if you are vomiting or have diarrhea to prevent dehydration

  • Monitoring your symptoms for signs of a worsening infection

Key Point: How Soon After Treatment Will You Start to Feel Better?

Individuals treated for ehrlichiosis with antibiotics — such as doxycycline — typically begin to see improvement within 24 to 48 hours after starting the course.

Complete recovery might also vary depending on the severity of the infection and the individual's overall health.

You should finish the entire course of antibiotics, even if you start to feel better, to prevent bacterial resistance and avoid further complications.

Can Ehrlichiosis Be Prevented?

Avoiding an ehrlichiosis infection primarily involves taking measures to prevent tick bites and reduce your risk of exposure to the disease.

Strategies to do this may involve:

  • Using tick and insect repellent that contains DEET, picaridin, or IR3535 on exposed skin

  • Wearing long-sleeved clothing and hats when visiting tick-infested areas

  • Wearing light-colored clothing that makes it easier to spot ticks before they reach the skin

  • Using landscaping to deter ticks, such as laying down wood chips or gravel barriers between wooded areas and lawns

  • Using pesticides in your yard to reduce tick populations, especially if you live in an area where they are prevalent

  • Performing regular tick checks after spending time outdoors and paying special attention to areas such as the armpits, around the ears, inside the belly button, and in the hair

  • Showering within two hours of coming indoors to reduce the risk factors associated with being bitten by a tick

  • Regularly inspecting your pets and using repellents to keep them protected from ticks

These strategies can help you guard against many tick-related illnesses — including ehrlichiosis — and help you prevent a bacterial infection.

What Happens If You Don’t Treat Ehrlichiosis?

Potential complications

If ehrlichiosis isn’t treated promptly, it can cause various complications that may have a significant impact on your health. These issues may include:

  • Renal failure

  • Internal bleeding

  • Inflammation on the brain

  • Heart failure

  • Seizures

  • Acute respiratory distress syndrome (ARDS) or respiratory failure

  • Disseminated intravascular coagulation (DIC)

  • Sepsis

Certain complications caused by untreated ehrlichiosis could be fatal, so it’s important to ensure you receive the proper medical care.

Outlook and prognosis

If the disease is treated quickly and correctly, the outlook for ehrlichiosis is generally good.

Individuals who start taking antibiotics soon after their symptoms appear usually don’t have serious complications or long-term health issues.

It’s important to note that while ehrlichiosis goes away with treatment, it can take a few weeks before you feel completely healthy.

When Should You See a Doctor About Ehrlichiosis?

Although the mortality rate of ehrlichiosis is quite low, it’s important to consult your doctor as soon as you develop any related symptoms.

This allows them to make a diagnosis and get you started on treatment as soon as possible, helping you to avoid potential complications.

You should also make an appointment with your doctor if you:

  • Discover any tick bites

  • Develop a rash following a recent tick bite

  • Notice that your ehrlichiosis symptoms don’t improve

  • Develop serious symptoms, such as breathing difficulties and unexplained bleeding

  • Have recently been exposed to ticks or live in an area where ehrlichiosis-causing ticks are prevalent

  • Are an immunocompromised individual

Where Can You Learn More About Ehrlichiosis?

While LifeMD doesn’t provide medical care for ehrlichiosis, we can help you manage any unpleasant symptoms of the disease.

A team of medical professionals can assist you with medications, prescriptions, and advice to cope with painful or uncomfortable symptoms caused by an infected tick bite.

Make your appointment today to take control of your health — all from the comfort of your own home.

LifeMD makes it easy to stay on top of your health because talking to a doctor, filling your prescriptions, getting your labs done—and more—are all easy and cost-effective. Come discover a healthcare solution built around you and your life.

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This article is intended for informational purposes only and should not be considered medical advice. Consult a healthcare professional or call a doctor in the case of a medical emergency.

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