Lyme Disease Symptoms and Testing: Why Diagnosis Can Be Difficult

Why can Lyme disease be hard to recognize?

The classic sign is a tick bite followed by a bull's-eye rash. Many cases start less clearly: the tick goes unnoticed, the rash looks different, or the first symptoms feel like a viral illness.

That uncertainty can delay a diagnosis, especially when the bite happened weeks earlier or during travel.

How does Lyme disease spread?

Lyme disease is a bacterial infection, most often from Borrelia burgdorferi in the U.S. It spreads through the bite of an infected blacklegged tick.

It is most common in the Northeast, mid-Atlantic and upper Midwest. Fewer cases are reported in Florida, so a trip to one of those regions is worth mentioning to your doctor.

Where Lyme disease is most common is noted in the CDC's overview of Lyme disease.

Which early symptoms should you watch for?

Early signs usually appear 3 to 30 days after a bite. They include fever, chills, headache, fatigue, muscle and joint aches, and swollen lymph nodes, sometimes without a rash.

The typical rash, erythema migrans, spreads out from the bite. It does not always form the familiar target shape, and its location can make it easy to miss.

What can happen if it is not treated?

Over days to months, the infection can reach other parts of the body. Later signs include severe headaches with a stiff neck, new rashes and drooping on one side of the face. Arthritis with painful swelling in large joints such as the knees can also develop.

Heart palpitations, dizziness, nerve pain, and shooting pains, numbness or tingling in the hands or feet can also appear. These need prompt medical care.

Early and later signs are listed in the CDC's guide to Lyme disease symptoms.

How does Lyme disease testing work?

The recommended blood test has two steps. If the first antibody test is positive or unclear, a second test confirms it.

Antibodies take several weeks to develop, so a test can be falsely negative in the first 4 to 6 weeks after infection. That is why a doctor also weighs the likelihood of a tick bite and your symptoms, not just the result.

The two-step test is explained in the CDC's guidance on Lyme disease testing.

How is Lyme disease treated?

Most cases are treated with 10 days to 4 weeks of antibiotics. Doxycycline, amoxicillin and cefuroxime axetil are the most common choices.

The medicine and the length of treatment depend on the stage and on whether the joints, heart or nervous system are involved. Your treating doctor makes that call.

Antibiotic treatment is described in the CDC's page on Lyme disease treatment.

What if symptoms continue after treatment?

Most people recover completely after a 2- to 4-week course. Some have lasting fatigue, body aches or trouble thinking, which is called post-treatment Lyme disease syndrome, and its cause is not known.

These symptoms also have many causes other than Lyme disease. A careful look at sleep, medicines, nutrient levels, thyroid function and other conditions comes before any conclusion.

Lasting symptoms after treatment are covered in the CDC's page on chronic symptoms and Lyme disease.

Could another tick-borne infection be involved?

The blacklegged tick can also carry the organisms behind anaplasmosis and babesiosis, and co-infections have been reported. Each can cause fever, fatigue and aches.

Symptoms alone cannot tell these apart. Travel history, geography and the right blood tests help your doctor decide what to look for.

Co-infections from the same tick are noted in the CDC's page on anaplasmosis transmission.

Where does a lab panel fit?

The Comprehensive Lab Panel is not a Lyme test, and Lyme testing is ordered on its own. When symptoms linger after treatment, lab markers such as thyroid function, iron and B12 can check other explanations for how you feel.

That work starts with a visit to Dr. Michael Meighen, MD. Any plan that follows belongs to the Restore phase of lab-guided care, alongside the care your treating doctor provides.

Common questions

How soon after a tick bite can Lyme disease be tested?

Antibody tests can be negative in the first 4 to 6 weeks, because the body needs time to make antibodies. If you develop a rash or fever after a bite, see a doctor right away and mention the bite.

Can you have Lyme disease without a rash?

Yes. Fever, chills, headache, fatigue, aches and swollen lymph nodes can appear without the rash. That is one reason the diagnosis is easy to miss.

What does the Lyme disease rash look like?

The rash, called erythema migrans, spreads outward from the site of the bite. It does not always form a target or bull's-eye shape, and it can appear somewhere hard to see. More rashes can appear elsewhere on the body later on.

Can Lyme disease cause tingling or nerve pain?

Yes. Without treatment, later signs can include nerve pain, shooting pains, and numbness or tingling in the hands or feet. Lyme disease is one of many known causes of nerve problems, so a doctor looks at the others too.

Is Lyme disease common in Florida?

It is far more common in the Northeast, mid-Atlantic and upper Midwest, and fewer cases are reported in Florida. A trip to a higher-risk region is worth telling your doctor about.

Does the Comprehensive Lab Panel test for Lyme disease?

No. Its markers cover hormones, thyroid function, metabolism, inflammation and nutrient status. Lyme disease is diagnosed with the two-step antibody test, your symptoms and your exposure history.

Should I take more antibiotics if symptoms continue?

That is a decision for your treating doctor. The CDC notes that lasting fatigue, aches and trouble thinking have many possible causes other than Lyme disease, so other causes are usually checked first.