Home/Lyme questions/Is Lyme disease autoimmune
Quick answerIs Lyme disease an autoimmune disease?
Lyme disease is an infection, but the immune system plays a big role in some lingering problems. Here is the difference, in plain language.
Quick answer
No. Lyme disease is a bacterial infection, not an autoimmune disease. It is caused by Borrelia burgdorferi bacteria spread by ticks and treated with antibiotics. However, in a small group of people, Lyme arthritis keeps going after the bacteria are gone. Researchers believe an overactive immune response, including autoimmune processes, drives that lingering joint inflammation.
- Lyme disease is a bacterial infection caused by Borrelia burgdorferi and, rarely, Borrelia mayonii (CDC).
- Some people still have joint swelling or pain after two courses of antibiotics. CDC says the cause is unknown but is thought to be driven by immune factors, more antibiotics have not been shown to help, and referral to a rheumatologist (a joint and immune specialist) should be considered.
Infection vs. autoimmune disease
An infection happens when a germ, like a bacterium or virus, gets into the body and multiplies. An autoimmune disease happens when the immune system mistakenly attacks the body’s own healthy tissue. Rheumatoid arthritis and lupus are examples.
Lyme disease is an infection. The bacteria enter through a tick bite and can spread to the joints, heart and nerves if untreated (CDC). That is why it is treated with antibiotics. Read what is Lyme disease for the basics.
When Lyme arthritis lingers: the immune connection
Lyme arthritis is joint swelling, most often in the knee, that usually appears one to a few months after infection (CDC). Most people get better with antibiotics. But in a subset of people, the arthritis continues and can even worsen after the bacteria have been killed. Doctors call this post-infectious (or antibiotic-refractory) Lyme arthritis.
A 2021 research review explains what scientists think is happening (Lochhead et al., 2021):
- During the infection, some people mount an unusually strong, poorly controlled inflammatory immune response.
- That response can continue after the bacteria are gone.
- In the joint lining, it is linked to tissue damage, autoimmune and cell-damaging processes, and scarring, features that resemble other chronic arthritis such as rheumatoid arthritis.
- The person’s genes likely help shape who develops it.
So while Lyme disease itself is not autoimmune, it can trigger immune-driven joint inflammation in some people. CDC suggests rheumatology referral in these cases. See our Lyme arthritis guide.
What about fatigue and other lingering symptoms?
Some people have fatigue, body aches or trouble thinking after treatment, which CDC calls post-treatment Lyme disease syndrome (PTLDS). CDC says the cause is unknown and that similar symptoms can follow other infections. It does not classify PTLDS as an autoimmune disease. Some patient advocates and clinicians believe ongoing infection or immune changes are involved; research continues. Read both views in chronic Lyme disease.
What this means for you
- If you have joint swelling after a tick bite or known Lyme disease, see your provider. Antibiotics are the first step.
- If swelling continues after treatment, ask whether a rheumatologist should see you.
- If you have an autoimmune condition and are worried about Lyme disease, share your full history with your provider; symptoms can overlap.
We are collecting real experiences about Lyme disease and immune-related symptoms from people who have lived it, shared with their permission. As stories come in, they will appear here, clearly marked as personal experience rather than medical advice.
Frequently asked questions
Can Lyme disease cause an autoimmune disease?
Research shows Lyme arthritis can trigger immune-driven joint inflammation that continues after the bacteria are gone in some people (Lochhead et al., 2021). Lyme disease itself is classified as an infection.
Is Lyme arthritis the same as rheumatoid arthritis?
No. Lyme arthritis is caused by infection and usually responds to antibiotics. Lingering post-infectious Lyme arthritis shares some features with rheumatoid arthritis in the joint lining, according to research.
Who treats arthritis that lingers after Lyme disease?
CDC suggests considering a referral to a rheumatologist when swelling or pain persists after antibiotic courses.