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What People with Weakened Immune Systems Need to Know About Mold

People with weakened immune systems include—

  • AIDS patients.
  • Cancer patients.
  • Transplant patients who are taking medications that can weaken their immune system.
  • People born with diseases that weaken their immune system.

If you have a weakened immune system, you may be at higher risk for getting a mold infection. These infections can lead to being hospitalized, or even dying. The risk of getting a mold infection depends on the strength of your immune system. Talk to your doctor about your risk for getting a mold infection.

If you have a weakened immune system, or care for someone who does, CDC answers some important questions about mold.

What are molds?

When people think of mold, they often think of a damp basement or a moldy piece of bread. But molds are found in many places.

Some molds live on and in our bodies without causing any harm or sickness, but other molds can cause infections. Some molds that cause infections are Aspergillus, Mucormycetes, Fusarium, and Scedosporium. Symptoms like a stuffy, runny, or itchy nose or throat irritation have been associated with moldy and damp indoor spaces. Molds also can cause asthma attacks in people with asthma who are allergic to molds. A few molds can cause more serious illnesses like lung infections.

Where are molds found?

Photo of mold inside a bathroom cabinet where condensation forms, courtesy of Terry Brennan (U.S. E.P.A.).

Although molds can be found almost anywhere, they grow best in warm, damp, and humid places. Molds spread by making tiny structures called spores. Unlike mold, spores can live in harsh places, like dry places where mold normally does not grow.

Outdoors, they can be found in shady, damp areas or places where leaves, compost heaps, grass, hay, soil, or other plants are breaking down. Indoors, they can be found on damp walls, floors, and ceilings where humidity levels are high (above 40%), like basements or showers. Buildings that have been flooded can have conditions that allow mold to grow. Although it is very hard to get rid of all mold growth and spores indoors, controlling moisture levels can help prevent mold from growing indoors.

What should people with weakened immune systems know about mold infections?

People with weakened immune systems are at higher risk for getting a mold infection. Most of the time, lung or sinus infections can develop, although other parts of the body can be affected. These infections usually require treatment in a hospital, and may take a long time to treat with antifungal drugs.

Are people with weakened immune systems more likely to get mold infections than others?

Yes. The risk of getting a mold infection is higher for people with a weakened immune system. For example, people who are being treated for cancer that affects the blood, bone marrow, or lymph nodes usually are at higher risk than those who have cancer of an organ, like the lung or liver. Also, people who received a stem cell or bone marrow transplant, or took medicine that lowers their body’s ability to fight infection, are at higher risk for mold infection.

People with AIDS and people who have a low white blood cell count, called neutropenia, due to cancer treatments may be at higher risk for mold infections.

I had a weakened immune system in the past, but do not now. Does this information apply to me?

If you had a weakened immune system in the past, but have a healthy immune system now, your risk is likely very low. For example, if you had chemotherapy in the past but have not received treatment recently, and now have a healthy immune system, your risk for getting a mold infection is likely very low. A doctor can determine your risk for mold infection.

What can people with weakened immune systems do to help reduce their risk of getting a mold infection?

One kind of mold infection (called Aspergillosis) can be found early with a blood test. This test sometimes is used to screen patients who have had a stem cell transplant. Some patients also may receive antifungal medicine to prevent fungal infections.

People with certain conditions like a poor ability to fight infection (due to very low white blood cell counts, organ transplant medicine, drugs that weaken your immune system, or drugs used to treat cancer) may consider avoiding buildings or other areas with high mold levels.

Although more research is needed to find the best ways to avoid mold infection, CDC recommends—

  • Working with your doctor to plan what to do if you get sick, including when you should call your doctor.
  • Writing down the type of cancer or conditions you have, treatment you have received and when you received it, your doctor’s name and contact information, and all of the medicines you are taking.
  • Making sure your vaccinations are up-to-date.

I found mold growing in my home. What should I do?

Generally, it is not necessary to identify the type of molds growing indoors, and CDC does not recommend routine sampling for molds. Sampling and culturing are not reliable in determining your health risk and can be expensive. Standards for judging what is, and what is not, a safe amount of mold have not been established.

If you are at risk for getting a mold infection and mold is seen or smelled inside your home, there may be a health risk. No matter what type of mold is present, it should be removed as well as any contaminated items, by someone who does not have a weakended immune system. You should get help removing the mold and contaminated items.

How do I remove mold from my home?

Photo of a person cleaning up mold wearing gloves, goggles, and an N-95 respirator, courtesy of U.S. E.P.A.

Someone who does not have a weakened immune system should clean up or remove the mold and stop more mold from growing. Replace water-damaged materials or dry them thoroughly. Mold can be removed from hard surfaces with commercial products, soap and water, or a bleach solution of no more than one cup of bleach in one gallon of water. If you use bleach to clean up mold—

  • Never mix bleach with ammonia or other household cleaners, as it will produce dangerous, toxic fumes.
  • Open windows and doors to provide fresh air.
  • Wear nonporous gloves and protective eyewear.
  • If the area to be cleaned is more than 10 square feet, see the U.S. Environmental Protection Agency’s guide, “Mold Remediation in Schools and Commercial Buildings.” This document also applies to other building types.
  • Follow the manufacturer’s instructions when using any cleaning product.

What are the symptoms of a mold infection?

Symptoms of a mold infection include fever, coughing or wheezing, body aches, headache, chills, fatigue, runny or stuffy nose, or in some cases, skin irritation (rash).

What should people with weakened immune systems do if they think they may have a mold infection?

If you have a weakened immune system and have symptoms of a mold infection, talk to your doctor and ask about mold infection testing. It is important to test for a mold infection early because early diagnosis and treatment can help stop the infection from getting worse.

Call your doctor and let the staff know you have a weakened immune system and think you may have a mold infection. Your doctor may recommend tests or prescribe medicine. Follow your doctor’s directions and take medicine as directed.

How are mold infections treated?

Antifungal drugs are prescription medicines that can help fight these infections. They also may prevent serious complications from mold infections, including death. It is very important to take antifungal drugs early to stop the infection from getting worse.

I live with or provide care for a person with a weakened immune system. What do I need to know about mold?

People with a weakened immune system should avoid being exposed to mold. If mold is in the home, someone who does not have a weakened immune system should clean it up and stop more mold growth.