Mold and Your Health, Who Is at Risk and When to See a Doctor

How Mold Can Affect People

Mold spores are in the air everywhere, indoors and out. Most people breathe small amounts every day without trouble. Problems usually start when mold grows indoors on damp materials and the amount in the air goes up, or when someone is especially sensitive.

The CDC lists common reactions to mold exposure. These include a stuffy nose, wheezing, coughing, sore throat, red or itchy eyes and itchy skin. People with a mold allergy may react more strongly. People with asthma can have attacks triggered by mold.

A major review by the Institute of Medicine in 2004 found enough evidence to link damp, moldy indoor spaces with upper respiratory symptoms, coughing, wheezing and asthma symptoms in people with asthma. Later research has continued to connect indoor dampness with breathing problems.

Mold can also cause infections, but mostly in people whose immune systems are weakened. For most healthy people, mold in a home is an irritant and an allergy trigger rather than an infection risk.

Some people have more unusual reactions to repeated heavy exposure, such as lung inflammation. These are less common and need a doctor to diagnose.

The takeaway is simple. Indoor mold is worth taking seriously and removing, especially if anyone in the home is in a higher risk group, but it is rarely an emergency for healthy adults.

Who Is More Vulnerable

The same patch of mold can mean very different things for different people in the same home. These groups are more likely to have problems and deserve extra protection.

• People with asthma. Mold is a known asthma trigger. Attacks may become more frequent or harder to control.
• People with allergies, especially a known mold allergy.
• People with a weakened immune system. This includes people receiving cancer treatment, people who have had an organ or stem cell transplant, people taking medicines that suppress the immune system, and people with conditions that weaken immunity. They can be at risk of mold infections.
• People with chronic lung disease, such as COPD or cystic fibrosis.
• Infants and young children, whose lungs are still developing and who breathe more air for their size.
• Older adults, who may have other health conditions that make breathing problems more serious.

If anyone in your home fits one of these groups, lower your threshold for action. A small patch you might clean yourself in an empty house deserves quicker attention, more care, and possibly a professional when someone vulnerable lives there.

If you are not sure whether a condition or medicine puts you at higher risk, ask the doctor who manages it.

When to See a Doctor

You do not need to see a doctor just because you found mold. You should make an appointment if any of these apply.

• You or a family member have new symptoms like coughing, wheezing, stuffy nose or itchy eyes that seem to get worse at home and better when you are away.
• Asthma is harder to control, or someone is using a rescue inhaler more often than usual.
• Someone with a weakened immune system has been exposed to mold and develops a fever, cough, chest pain or trouble breathing.
• An infant or young child has ongoing coughing, wheezing or breathing trouble.
• Symptoms last more than a couple of weeks or keep coming back.
• You have a skin rash that appeared after handling moldy items.

Get emergency care right away for severe shortness of breath, lips or face turning blue, confusion, chest pain, or an asthma attack that does not respond to the usual rescue medicine. Call 911.

Tell the doctor about the mold even if you are not sure it is related. Symptoms from mold look like colds, seasonal allergies and other conditions, so the history you give helps the doctor sort it out.

What to Tell Your Doctor

A clear history is often more useful to a doctor than any test. Before the visit, write down the facts.

• When symptoms started and whether they changed after a leak, a flood or a move.
• Where symptoms are worse, such as at home, in one room, at work or at school, and whether they ease when you are away.
• What you have found, including where mold or water damage is, how large it is and how long it has been there. Bring photos.
• Who else is affected in the home, including children.
• Any cleanup you have done and whether symptoms flared during it.
• Your current health conditions and medicines.

Keep a simple symptom diary for two weeks if you can. Note the date, the symptoms, where you were, and anything unusual like a rainstorm or a leak.

You may see tests sold directly to the public that claim to measure mold toxins in urine or blood. Talk to your doctor before paying for these. Your doctor can explain what a given test would and would not tell you and whether it would change your care.

If your doctor asks for information about exposure at home, an independent mold assessment with a written report can help. That is one of the few times home mold testing is clearly worth it.

Protecting Your Family During Cleanup

Cleaning mold stirs up spores, so the cleanup itself is often when exposure is highest. Plan it around the people at risk.

• People in higher risk groups should not do the cleanup. Have a healthy adult do small jobs, or hire a specialist.
• Keep vulnerable people out of the area during the work and until it is dry and clean. For larger jobs, some families have them stay with relatives until the work passes clearance.
• Close off the work area with doors or plastic sheeting, turn off the HVAC to that area and tape over vents so spores do not travel.
• The person cleaning should wear an N95 respirator at a minimum, goggles without vent holes and long gloves, and change clothes before entering the rest of the house.
• Bag moldy materials inside the work area before carrying them out.
• Clean with detergent and water and a HEPA vacuum, not dry sweeping, which throws spores into the air.

The EPA’s guidance treats about 10 square feet as the line for DIY mold cleanup. With a vulnerable person in the home, it is reasonable to call a specialist for smaller jobs too. A professional uses containment and air filtration that a homeowner usually cannot match.

Avoid ozone generators and chemical foggers. They do not remove mold, and ozone irritates the lungs, which is the last thing someone with asthma needs.

Lowering Exposure Day to Day

The most effective way to protect health is to keep mold from growing in the first place. That means controlling moisture.

• Keep indoor humidity between 30 and 50 percent. The EPA recommends staying below 60 percent. A hygrometer costs about $10 to $20.
• Fix leaks promptly and dry wet materials within 24 to 48 hours.
• Run bathroom and kitchen exhaust fans that vent outdoors.
• Use a dehumidifier in basements and damp rooms, and empty or drain it regularly.
• Clean with a HEPA vacuum rather than a standard vacuum, especially in bedrooms.
• Change HVAC filters on schedule and keep the condensate drain clear.
• Avoid carpet in bathrooms and basements.

A portable HEPA air cleaner in a bedroom can reduce airborne particles, including some spores. It is a helpful extra for a person with asthma or allergies, but it does not fix a mold problem. The source still has to be removed.

If you rent, report leaks and mold to your landlord in writing, with photos and dates. If a household member has asthma or a weakened immune system, say so in the notice. That helps the landlord understand the urgency.

Over time, a dry home is a healthier home. Most people who have mold-related symptoms feel better once the moisture is fixed and the growth is removed.

Step by Step

1. Identify Who Is at Higher Risk

   List anyone in the home with asthma, allergies, lung disease or a weakened immune system, plus infants, young children and older adults. Plan the cleanup around them.

2. Separate People From the Mold

   Close off rooms with visible mold. Keep vulnerable people out, and consider a temporary stay elsewhere for larger jobs.

3. Start a Symptom Diary

   Write down symptoms, dates and where they happen. Note any leaks, storms or cleanup work.

4. See a Doctor if Needed

   Make an appointment if symptoms get worse at home, asthma is harder to control, or someone with a weak immune system develops fever or cough. Call 911 for severe breathing trouble.

5. Fix the Moisture Source

   Stop the leak or high humidity that fed the mold. Keep indoor humidity between 30 and 50 percent.

6. Choose Who Cleans It

   A healthy adult with an N95, goggles and gloves can handle small areas under about 10 square feet. With a vulnerable person in the home, consider a specialist even for smaller jobs.

7. Keep It From Coming Back

   Use exhaust fans, a dehumidifier and a HEPA vacuum. Check the repaired area monthly for any return of growth or smell.

Mistakes That Make It Worse

• Having the family member with asthma do the scrubbing because they are home during the day.
• Assuming symptoms are just a cold when they keep improving every time you leave the house.
• Paying for direct-to-consumer mold toxin tests before talking to a doctor.
• Running an ozone machine to clear mold odor. Ozone irritates the lungs and does not remove mold.
• Relying on an air purifier while the leak and the mold stay in place.

Where You Live Matters