What Happens If Lyme Disease Goes Untreated?

What happens if Lyme disease goes untreated? Can it eventually affect your brain, heart, nerves, or joints? And what happens if you never realized you were bitten by a tick in the first place?

Lyme disease is generally easier to treat when it is recognized early. Without treatment, however, the infection can spread beyond the original site of the tick bite and potentially cause neurological, cardiac, and joint complications.

That doesn't mean every person with untreated Lyme disease will follow the same path or develop every possible complication. Lyme disease can present very differently from one person to another.

Here's what we know about how untreated Lyme disease can progress.

What Is Lyme Disease?

Lyme disease is an infection caused primarily by Borrelia burgdorferi bacteria in the United States. It is transmitted to humans through the bite of infected blacklegged ticks.

Early symptoms can appear anywhere from about 3 to 30 days after a tick bite.

Common early signs and symptoms can include:

• Fever, chills, headache, fatigue, and swollen lymph nodes
• Muscle and joint aches
• An expanding erythema migrans (EM) rash

The erythema migrans rash is one of the most recognizable signs of Lyme disease, but not everyone develops or notices one.

According to the CDC, an erythema migrans rash occurs in approximately 70–80% of infected people.

The rash also doesn't always look like the perfectly circular "bull's-eye" rash commonly associated with Lyme disease. Its appearance can vary considerably.

Another problem is that blacklegged ticks can be extremely small, particularly during the nymph stage. A person can therefore develop Lyme disease without ever remembering a tick bite.

What Happens If Lyme Disease Isn't Treated?

If Lyme disease isn't treated during the early stage, the bacteria can spread beyond the original site of infection.

This is commonly referred to as disseminated Lyme disease.

As the infection spreads, symptoms may begin appearing in other parts of the body. These can include additional erythema migrans rashes, facial palsy, nerve pain, numbness or tingling, severe headaches, neck stiffness, dizziness, heart symptoms, and joint problems.

It's tempting to think about Lyme disease as a perfectly predictable progression from "Stage 1" to "Stage 2" and eventually "Stage 3."

In reality, it isn't always that simple.

Symptoms and stages can overlap, and two people with Lyme disease may have very different experiences. Someone may develop a particular complication while never experiencing several of the symptoms commonly associated with Lyme disease.

Can Untreated Lyme Disease Affect the Brain and Nervous System?

Yes. Lyme disease can affect the nervous system, a condition generally referred to as neurologic Lyme disease or Lyme neuroborreliosis.

Neurological complications can occur when the infection affects the peripheral or central nervous system.

Possible manifestations include facial palsy, shooting nerve pain, numbness, tingling, weakness, severe headaches, and symptoms of meningitis such as neck stiffness.

One particularly recognizable manifestation is facial nerve palsy, which can cause weakness or drooping on one or both sides of the face.

This is one reason Lyme disease doesn't always look like the stereotypical combination of a tick bite, bull's-eye rash, and flu-like illness.

If Lyme disease has progressed, neurological symptoms may become a much more prominent part of the clinical picture.

Can Untreated Lyme Disease Affect the Heart?

Lyme disease can also affect the heart in a small percentage of cases.

This complication is called Lyme carditis.

Lyme carditis occurs when Lyme bacteria reach heart tissue and interfere with the electrical signals coordinating the heartbeat. One of the best-known complications is atrioventricular (AV) heart block.

Symptoms may include heart palpitations, chest pain, shortness of breath, lightheadedness, or fainting.

Because disturbances in the heart's electrical system can become serious, possible cardiac symptoms shouldn't simply be assumed to be Lyme disease or managed at home.

New chest pain, significant shortness of breath, fainting, or concerning changes in heart rhythm warrant prompt medical evaluation.

Can Untreated Lyme Disease Cause Arthritis?

Another well-established complication of untreated Lyme disease is Lyme arthritis.

Lyme arthritis can develop months after the initial infection and typically causes noticeable swelling in one or a few joints.

The knee is particularly common.

Interestingly, the amount of swelling can sometimes appear disproportionate to the amount of pain someone experiences. Episodes of joint swelling may also come and go.

Without appropriate treatment, Lyme arthritis can persist and, in some cases, contribute to lasting joint problems.

This is another example of why untreated Lyme disease can look so different depending on where and how the infection manifests.

Does Untreated Lyme Disease Always Get Worse?

Not necessarily.

It's important not to interpret a list of Lyme complications as a guaranteed progression that happens to everyone who doesn't immediately receive treatment.

Not everyone with untreated Lyme disease develops neurologic Lyme disease, Lyme carditis, and Lyme arthritis. The course and severity of illness can vary considerably.

It's equally important not to assume that every unexplained headache, palpitation, painful knee, episode of fatigue, or neurological symptom must be caused by Lyme disease.

These symptoms have many potential causes.

A healthcare professional may consider your symptoms, potential exposure to ticks, physical examination, medical history, and appropriate laboratory testing when evaluating whether Lyme disease could be responsible.

The important point is that Lyme disease can disseminate when it isn't treated, which is why recognizing possible Lyme disease early matters.

What If You Never Saw a Tick or Bull's-Eye Rash?

This is one of the reasons Lyme disease can sometimes be missed.

You don't necessarily have to remember being bitten by a tick to have Lyme disease.

Ticks can attach in areas that are difficult to see, and immature blacklegged ticks can be extremely small. A tick may also detach before someone realizes it was there.

Likewise, the absence of a classic bull's-eye rash doesn't automatically rule out Lyme disease.

The CDC estimates that approximately 70–80% of infected people develop an erythema migrans rash, meaning a minority do not develop or recognize one.

If you've spent time in tick habitat and subsequently develop compatible symptoms, it's worth discussing the possibility with a healthcare professional even if you don't remember finding a tick.

Untreated Lyme vs. Symptoms That Continue After Treatment

There's another distinction that is especially important in conversations about chronic or persistent Lyme symptoms:

Untreated Lyme disease isn't the same situation as continuing to experience symptoms after receiving recommended antibiotic treatment.

Some people experience prolonged fatigue, pain, difficulty thinking, or other symptoms following treatment for Lyme disease. The CDC refers to prolonged symptoms following recommended treatment as Post-Treatment Lyme Disease Syndrome (PTLDS) when certain criteria are met.

Why these symptoms persist isn't completely understood and continues to be studied.

Persistent symptoms therefore shouldn't automatically be interpreted as proof that someone still has an untreated active Borrelia infection.

This is a much more complicated area of Lyme disease and deserves to be considered separately from what happens when an initial Lyme infection receives no treatment.

How Long Can Lyme Disease Go Untreated?

There isn't one timeline that applies to everyone.

Early symptoms may begin within days or weeks of infection, while certain later manifestations can develop weeks or months afterward.

That variability is another reason waiting for Lyme disease to follow a particular sequence of symptoms can be misleading.

Someone doesn't necessarily need to experience every "early" symptom before developing later manifestations.

If Lyme disease is a realistic possibility, earlier evaluation is generally preferable to waiting to see whether more severe symptoms eventually appear.

What Should You Do If You Think You Have Lyme Disease?

If you've recently had a tick bite, possible tick exposure, an expanding rash, or symptoms that could be consistent with Lyme disease, speak with a qualified healthcare professional.

Diagnosis isn't based on one symptom alone, and testing can have limitations depending on when the infection occurred.

Early Lyme disease is generally easier to treat than disease that has been allowed to disseminate.

And if you're already dealing with Lyme disease and feel overwhelmed by conflicting protocols, supplements, diets, and recovery advice, remember that more information isn't always what you need.

Sometimes you need a clear place to start.

Join the Free 4-Day Lyme Recovery Experience

If you've already been diagnosed or treated and are trying to figure out what to do next, I'm hosting a free 4-Day Lyme Recovery Experience beginning September 21.

We'll simplify the recovery process and focus on the foundational pieces that matter most, so you can stop bouncing between dozens of different strategies without knowing what to prioritize.

Register free at LymeWars.com/live.

Frequently Asked Questions About Untreated Lyme Disease

What happens if Lyme disease goes untreated for years?

Untreated Lyme disease can potentially lead to later complications involving the joints and nervous system. However, Lyme disease doesn't follow exactly the same course in every person. Someone experiencing symptoms years after possible exposure should be medically evaluated rather than assuming Lyme disease is necessarily the cause.

Can untreated Lyme disease affect the brain?

Lyme disease can affect the nervous system and cause neurologic complications. Possible manifestations include facial palsy, nerve pain, numbness or tingling, and meningitis symptoms such as severe headache and neck stiffness.

Can Lyme disease damage your heart?

Lyme carditis can interfere with the heart's electrical conduction system and, in some cases, cause heart block. Symptoms such as fainting, chest pain, significant shortness of breath, or abnormal heart rhythms require prompt medical attention.

What joints are affected by Lyme disease?

Lyme arthritis most commonly affects large joints, particularly the knee. Significant swelling may occur and can sometimes come and go.

Can you have Lyme disease without a bull's-eye rash?

Yes. Not everyone with Lyme disease develops or notices an erythema migrans rash. Even when a rash occurs, it doesn't always have the classic bull's-eye appearance.

Can you have Lyme disease without remembering a tick bite?

Yes. Blacklegged ticks can be very small and may attach in difficult-to-see areas of the body. Many people diagnosed with Lyme disease don't remember being bitten.

Is untreated Lyme disease the same as chronic Lyme disease?

No. "Untreated Lyme disease" describes an infection that hasn't received treatment. Persistent symptoms following recommended treatment are a separate clinical situation, and the causes of prolonged symptoms following treatment continue to be studied.

Is Lyme disease easier to treat when caught early?

Generally, yes. Early recognition and appropriate antibiotic treatment can reduce the risk of Lyme disease progressing to later complications involving the nervous system, heart, or joints.

Medical disclaimer: This article is for educational purposes only and isn't intended to diagnose, treat, cure, or prevent any disease or replace individualized medical advice from a qualified healthcare professional.