Lyme Disease and Mold Exposure

Quick answer

Mold can cause real health problems, mostly a stuffy nose, cough, wheezing, eye or skin irritation and asthma flares. People with weak immune systems can get mold lung infections (CDC). There is no established evidence that mold causes or worsens Lyme disease. “Mold toxicity” claims are not supported by medical toxicology experts, and urine mycotoxin tests are not validated.

What mold exposure can do to your health

Mold exposure symptoms are mostly allergy-like and respiratory. A major 2004 review by the Institute of Medicine (now part of the National Academies) found sufficient evidence linking damp indoor spaces to:

• Upper respiratory symptoms, such as a stuffy or runny nose and sore throat
• Coughing and wheezing
• Asthma symptoms in people with asthma who are sensitized to mold

CDC adds that the same review linked indoor mold to hypersensitivity pneumonitis (an immune reaction in the lungs) in susceptible people, and that newer studies suggest early mold exposure may contribute to asthma in some children who are genetically prone to it. People with very heavy exposure, such as farmers handling moldy hay, can develop fever and shortness of breath (CDC).

These are real problems that deserve attention, whether or not you also have Lyme.

What you may read online: “mold toxicity” and CIRS

If you search for Lyme and mold, you will likely find terms like “mold toxicity,” “mycotoxin illness” and “chronic inflammatory response syndrome” (CIRS). Some practitioners use these terms for a long-lasting, body-wide illness they attribute to toxins from mold in water-damaged buildings.

Supporters of CIRS point to a small number of published reports, most describing one treatment approach known as the Shoemaker protocol. A review in Annals of Medicine and Surgery counted 13 articles on CIRS treatment, 11 of them describing that protocol. The review did not formally grade the strength of that evidence.

Medical toxicologists see it differently. In a 2025 position statement, the American College of Medical Toxicology (ACMT) said:

• The amount of mycotoxin a person breathes in a moldy home or office is generally far below levels known to cause harm.
• There is no documented evidence that breathing indoor mold or mycotoxins causes long-term toxic brain injury, and ongoing thinking or nerve symptoms should prompt a search for other causes.
• “Detox” tests and treatments based on presumed mold toxicity, rather than allergy, are medically inappropriate and costly.
• Health concerns about damp spaces are best approached as allergy problems, together with prompt repair of water damage.

You may also read that mold exposure keeps people with Lyme from getting better. We did not find peer-reviewed studies showing that mold causes Lyme, worsens the infection or blocks recovery.

Why patients report overlap between Lyme and mold

The overlap people describe is understandable, even without a proven link:

• Shared, non-specific symptoms. Fatigue, aches and trouble thinking have many possible causes, including other infections, medications, diabetes and cancer (CDC). They are not specific to Lyme or to mold.
• Real symptoms from a damp home. Mold can cause breathing and allergy symptoms that add to how unwell someone feels.
• Searching for answers. Lingering symptoms after Lyme have no known cause (CDC), so it makes sense to look at everything, including your home.

Read more about post-treatment Lyme disease syndrome and chronic Lyme disease.

Urine mycotoxin tests and home mold tests

Some labs sell urine tests for mycotoxins directly to consumers. In 2015, CDC’s occupational health institute (NIOSH) described a case in which a worker’s urine “toxic mold” test led to a diagnosis of “mold toxicity,” nonstandard treatments, and more than $25,000 spent removing building materials, even though the office had no water damage or significant mold growth. NIOSH pointed out that:

• No urine mycotoxin test is approved by the FDA for accuracy or clinical use.
• Healthy people have small amounts of mycotoxins in their urine from food, and no level has been shown to predict disease.
• A lab’s quality certification does not show that a test can diagnose illness.
• CDC does not recommend urine or blood mycotoxin testing for people in water-damaged buildings.

ACMT agrees that finding mycotoxins in urine should not be blamed on past mold inhalation, and it does not recommend mycotoxin antibody tests to assess exposure. Allergy tests can help diagnose mold allergy, but they do not measure mycotoxin exposure (ACMT).

How to deal with dampness and mold at home

EPA says the key to mold control is moisture control. Its guidance for homeowners includes:

1. Fix the water problem first. If you clean mold without fixing the leak or dampness, the mold will likely come back.
2. Dry wet areas fast. Dry water-damaged areas and items within 24 to 48 hours.
3. Lower humidity. Keep indoor humidity below 60%, ideally between 30% and 50%.
4. Clean hard surfaces. Scrub mold off hard surfaces with detergent and water, then dry completely. Moldy carpet or ceiling tiles may need to be thrown away.
5. Do not paint over mold. Clean and dry the surface first.
6. Protect yourself. Wear an N-95 respirator, gloves and goggles. EPA does not recommend bleach as routine practice, and bleach must never be mixed with ammonia cleaners.
7. Know when to call a professional. Get help if mold covers more than about 10 square feet, if there was sewage or other contaminated water, or if your heating and cooling system may be contaminated.

EPA also suggests talking with a health professional before cleanup if you have health concerns. If breathing or allergy symptoms persist, your doctor may refer you to an allergist.

For more on conditions that overlap with Lyme, see our Lyme and other conditions hub, including Lyme and MCAS, and step 6 of our guide, living well with Lyme.

Frequently asked questions