Lyme disease is a bacterial infection that can sometimes affect the heart. One complication of Lyme disease is Lyme carditis, which may sometimes mimic high blood pressure. Treatment for Lyme disease can also cause a person to experience changes in blood pressure.

A further complication of Lyme carditis is heart block, which can cause heart rate irregularities and a slower-than- usual heartbeat.

This article explores the link between Lyme disease and high blood pressure. It also discusses other connections between Lyme disease and heart health, alongside the symptoms, treatment, and outlook.

A person with Lyme disease getting their blood pressure checked.Share on Pinterest
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As a 2022 review explains, Lyme disease is an infectious disease. People develop Lyme disease due to an infection from the Borrelia burgdorferi bacteria. The bacteria spread to people via the bites of infected ticks.

There is no scientific evidence that Lyme disease itself can cause high or low blood pressure. However, Lyme disease can affect the heart in ways that mimic high blood pressure. Moreover, treatment for Lyme disease sometimes causes changes in blood pressure.

Learn more about Lyme disease.

Lyme carditis

Scientists define Lyme carditis as any form of Lyme disease that affects the heart. Lyme carditis shares some symptoms with high blood pressure.

High blood pressure itself is usually asymptomatic, and symptoms only develop once it has caused significant health issues. However, the British Heart Foundation notes that some symptoms of high blood pressure can include:

Lyme carditis can also cause chest pain and shortness of breath.

Learn more about Lyme carditis and the heart.

Jarisch Herxheimer reaction (JHR)

JHR is a reaction to antibiotic treatment for certain bacterial infections. These infections include Lyme disease.

As a 2022 review explains, JHR can sometimes cause an increase in blood pressure and a subsequent decrease in blood pressure.

Lyme carditis and JHR are different ways B. burgdorferi bacteria can affect the heart.

Both conditions can cause several different symptoms. These sometimes include changes in heart rate.

Lyme carditis

The Centers for Disease Control and Prevention (CDC) list the following symptoms of Lyme carditis:

Research shows that heart block is the most common complication of Lyme carditis. Heart block is when there is a dysfunction of the atrioventricular node. This node has the function of coordinating the heart’s rhythm.

During heart block, an individual’s heart starts beating unusually. For instance, heart block can cause an irregular beating. It can also cause bradycardia — when the heart beats too slowly.


Scientists continue to investigate why JHR occurs. Some researchers believe that JHR may develop when antibiotic treatment causes the infecting bacteria to die. This process could release harmful chemicals into the body, causing inflammation.

There are many different symptoms of JHR. These include:

JHR can also cause an increase in heart rate.

A doctor needs to prescribe antibiotics to treat Lyme disease.

Lyme disease

According to the 2022 review, antibiotic therapy remains the gold standard for treating Lyme disease.

In most adults, doxycycline is useful. For pregnant individuals, doctors prefer to recommend ceftriaxone. Finally, amoxicillin is the most appropriate antibiotic for children under 8 years of age.

Learn more about how doctors cure Lyme disease.

Lyme carditis

As the CDC explains, antibiotics are also important for treating Lyme carditis. In all cases, the recommendation is for 14–21 days of antibiotics. However, there are important differences between adults and children.

The severity of Lyme carditis is also relevant to treatment. In milder cases of Lyme carditis, doctors recommend oral antibiotics.

The table below summarises antibiotic regiments for mild Lyme carditis:

doxycyclineadults100 mg, twice daily
children4.4 mg/kg, divided into 2 doses
amoxicillinadults500 mg, 3 times per day
children50 mg/kg, divided into 3 doses
cefuroximeadults500 mg, twice daily
children30 mg/kg, divided into 3 doses

In severe cases of Lyme carditis, doctors recommend 1 dose of intravenous ceftriaxone.

For adults, the recommendation is 2 grams (g) of ceftriaxone. For children, the recommendation is 50–75 milligrams of ceftriaxone per kilogram of body weight. The daily dose cannot exceed 2 g.

Some people with Lyme carditis also require a temporary pacemaker.


When JHR occurs, doctors should pause antibiotic treatment until the complication resolves.

Doctors do not always treat JHR. However, experts note that certain antibodies and steroids can reduce symptoms. These symptoms include changes in heart rate and blood pressure.

The outlook for Lyme disease is generally good. Research suggests that around 95% of people with Lyme disease fully recover with antibiotic treatment. However, some people will experience symptoms for months and sometimes years after treatment.

Many people recover from Lyme carditis. However, the CDC notes that some individuals will require a temporary pacemaker.

Scientists believe that JHR typically resolves on its own within 24 hours. Medications are often effective in treating this complication.

In some cases, JHR can cause a life threatening drop in blood pressure. However, this is quite rare.

Lyme disease is a bacterial infection that can cause many different symptoms.

There is no scientific evidence that Lyme disease can cause high blood pressure. However, it can cause Lyme carditis, which can share similar symptoms with high blood pressure, such as chest pain and shortness of breath.

During treatment, JHR can cause changes in blood pressure. Although these often disappear on their own, they can sometimes be dangerous.