Lyme Disease – Diagnosis, Symptoms, and Treatment

Medically reviewed by Dr. Po-Chang Hsu, MD, MS

Medical Professional

Updated - December 14, 2020

Dr. Po-Chang Hsu is a medical doctor from Tufts University in Boston, Massachusetts, interested in pediatrics and neonatology.

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What is Lyme Disease?

Lyme disease is an infectious disease caused by the organism Borrelia burgdorferi.  The condition is spread by the Ixodes tick bite, which is typically transmitted to humans by the white dear.  Lyme disease is most often seen in North-eastern and mid-Western states such as Connecticut and Wisconsin.  The bite of the Ixodes tick results in the spread of B. burgdorferi through the blood stream.  Patients often develop a characteristic bullseye rash (target rash) at the initial site of inoculation.  They subsequently create the rash spread across the body (erythema migrans), followed by systemic flu-like symptoms.

Long-term complications include Lyme carditis (inflammation of the heart), which results in cardiac conduction abnormalities.  Patients also frequently develop neurologic abnormalities and chronic migratory arthritis.

What Causes Lyme Disease?

Lyme disease is caused by the bacteria Borrelia burgdorferi, which is part of the spirochete family.  This bacteria is hosted on the Ixodes tick, which frequently resides on white dear in the Northeastern and mid-Western United States regions.  Once the Ixodes tick bites an individual, bacteria enter the circulation and disseminate widely.  A characteristic rash called a bullseye or target rash develops at the bite location.  As the bacteria spread, individuals develop a wide-spread rash over the body accompanied by systemic symptoms such as fever and malaise.  The bacteria can infect organs such as the nervous system, heart, and joints.  Untreated patients may develop chronic infection, which is frequently complicated by migratory arthritis, heart disease (carditis), cardiac conduction abnormalities, and peripheral neuropathy.

How Common is Lyme Disease?

In specific geographic locations in the United States, Lyme disease is relatively common and responsible for a fair number of primary care visits.  The condition may require referral to an infectious disease specialist, mainly if first-line and conservative measures are unsuccessful.  Other specialists may also need to be involved in a patient’s care, including a cardiologist, neurologist, and orthopedic surgeon.

Approximately 251,000 cases of Lyme disease were reported in the United States from 2005-2014.  Some studies suggest that Lyme disease affects about 300,000 Americans annually.  It was the 5th most common reportable disease in the United States in 2014.  Lyme disease peaks at ages 5-10 and 35-55.  More than 50% of cases occur in males.  The most frequently affected regions are forested areas in the northeastern United States, such as Connecticut, Delaware, New York, Maine, Maryland, and Massachusetts.

Signs and Symptoms

Lyme disease’s symptoms depend on the stage, such as early localized disease, early disseminated disease, and late infection.  During the early stages, patients typically develop a characteristic bullseye rash (target rash) at the inoculation’s initial site.  They subsequently develop the rash spread across the body (erythema migrans), followed by systemic symptoms that can mimic flu, such as fever, body aches, headache, and arthralgias.  Long-term complications include Lyme carditis (inflammation of the heart), which results in cardiac conduction abnormalities and occasionally leads to heart failure.  Patients also frequently develop neurologic abnormalities such as meningitis, facial palsy, and polyneuropathy.  Polyneuropathy is often characterized by sensory loss and paresthesias in the extremities.  Some patients develop a subtle form of dementia.  Individuals also often develop chronic arthritis in one or a few joints.


Lyme disease is suggested based on symptoms and physical examination but typically confirmed with laboratory studies.  Serologic testing is often performed with an enzyme-linked immunosorbent assay (ELISA) followed by a Western blot.  Polymerase chain reaction (PCR) testing of the cerebrospinal or joint fluid can help confirm the diagnosis.

Commonly ordered blood tests include a CMP (comprehensive metabolic panel), CBC (complete blood cell count), thyroid function (TSH, free T4), and urine analysis.  An EKG (electrocardiogram) is typically obtained to evaluate the electrical activity of your heart.  If you have symptoms or signs of heart failure, the healthcare providers will order a chest x-ray and ultrasound of the heart (echocardiogram).

Individuals with peripheral neuropathy often receive nerve conduction studies and electromyography (EMG).  Your doctor may obtain a brain MRI if you have cognitive dysfunction.  Occasionally, they recommend a lumbar puncture (spinal tap) to analyze your cerebrospinal fluid for evidence of Borrelia burgdorferi infection.

If you have joint pain, your doctor may obtain an x-ray of the affected joint.  Sometimes, inflamed joints such as the knee receive arthrocentesis – during this procedure, your doctor will insert a sterile needle into the joint and drain fluid to send for further laboratory analysis.

Lyme Disease Medication and Treatment

Lyme disease is treated with antimicrobial agents that have activity against Borrelia burgdorferi.  The antibiotic regimen and dosing schedule is based on the stage of illness and organs involved.  A significant percentage of patients experience worsening of their symptoms in the first 24 hours of therapy – this is called the Jarisch-Herxheimer reaction.

Adults and children age ≥8 with early Lyme disease generally receive one of the following oral antibiotics:

Doxycycline is typically avoided in children age <8 due to potential adverse effects on bone growth.  These children usually receive Amoxil (amoxicillin) or Ceftin (cefuroxime axetil).  Pregnant or lactating women should also avoid doxycycline use due to potential teratogenic effects.

There is some evidence to suggest that oral antibiotics can also be beneficial in asymptomatic patients with positive blood tests.  This typically includes a single 28-day course of oral doxycycline or amoxicillin.

Patients with meningitis or Lyme neurologic disease often require intravenous (IV) antibiotics for about 28 days.  Those with early disseminated disease and symptomatic carditis complicated by heart block often require hospital admission with IV antibiotics.  Common agents include:

  • Rocephin (ceftriaxone)
  • Claforan (cefotaxime)
  • Penicillin G

Patients with Lyme carditis and heart block also often require the placement of a temporary pacemaker.


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  2. Stanek G, Wormser GP, Gray J, Strle F. Lyme borreliosis. Lancet 2012; 379:461. -
  3. Sanchez E, Vannier E, Wormser GP, Hu LT. Diagnosis, Treatment, and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: A Review. JAMA 2016; 315:1767. -


Medication for Lyme Disease

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.