Black Mold Exposure

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is black mold exposure?

Stachybotrys chartarum, which is usually what people are referring to when they say “black mold,” is a blackish-green toxic mold. Like all types of mold, black mold is a fungus that can grow anywhere water is allowed to sit for an extended time in materials that can feed it, such as carpet, drywall or food.

Molds are found everywhere and are a common allergen in the air no matter where you go. However, mold that people encounter in everyday situations is not harmful because the amount inhaled is low and it can be well tolerated by healthy individuals. Black mold, just like all molds, should be avoided in large amounts and, if found, should be removed and cleaned.

People who live in humid climates have a higher likelihood of frequent black mold exposure in large amounts. Having carpet in bathrooms and other areas where it may stay damp can increase someone’s risk of exposure. Anyone whose job involves working with moldy materials also may experience black mold exposure symptoms.

Common symptoms resemble seasonal allergy symptoms: itchy, watery eyes, cough, and stuffy nose. Some people, such as those with asthma, may also experience shortness of breath. While all types of mold exposure, including black mold exposure, should be avoided in large amounts, there’s no scientific evidence that it can cause life-threatening health conditions, such as cancer or lung disease.

If you have a mold allergy, you can treat the symptoms with prescription allergy drugs or over-the-counter medications. But the best way to reduce allergy symptoms is to get rid of the mold, wherever it may be occurring.

What are the symptoms of black mold exposure?

If you have been exposed to black mold, you may experience symptoms of mild to moderate allergic reaction. Sometimes black mold exposure effects result in secondary health problems. It’s important to pay attention to your symptoms to know whether you need medical attention. Any symptoms that persist should be evaluated by a doctor.

Common allergy symptoms of black mold exposure

Allergy symptoms, rather than serious health problems, are the most common symptoms related to mold exposure. If you have a sensitivity to mold, you may experience these symptoms, which may be mild or severe. The most common allergy symptoms of black mold exposure include:

Secondary conditions caused by black mold exposure

Some people may develop other health conditions when they are exposed to black mold. Often these are people who have underlying health conditions, like immunity problems or asthma. People who take immunosuppressive drugs, such as those who have had an organ transplant, may also have worse symptoms or develop serious health conditions due to black mold exposure. These secondary conditions include:

  • Pneumonia

  • Antibiotic-resistant sinusitis

  • Infection that spreads to the brain or blood stream

Most of the time when people experience symptoms of black mold exposure, the symptoms are irritating but not serious. However, if you’re experiencing difficulty breathing or you feel sick beyond mild allergy symptoms, it’s a good idea to check with your doctor. If allergy symptoms persist, a doctor may be able to evaluate you for potential allergens, whether those be mold or some other allergen you may need to avoid.

What does black mold look like?

The fungus known as black mold can grow anywhere water is allowed to sit for an extended time in materials that can feed it, such as carpet, drywall or food. It is blackish-green in color.

Black mold on a wall:


Black mold growing on a moisture-laden old window pane:

Old window pane with wood damage and mold

What causes black mold exposure?

Exposure to black mold happens all the time because mold is everywhere. However, mold usually is not dangerous at the levels present in normal, everyday amounts. Exposure becomes a health concern when the amount of inhaled mold is a much higher amount due to living or working in an area where mold is allowed to grow. These settings are usually working or living in humid or damp buildings, working with moldy materials, or accidentally eating moldy food.

When mold grows in buildings or on materials and then dries, disturbing the dried mold releases spores into the air, which are then inhaled. Long-term exposure can result in allergy or more serious symptoms.

What are the risk factors for black mold exposure?

Some people may have an increased risk of being exposed to higher levels of black mold. Risk factors for exposure to high amounts of black mold include:

  • Living in humid climates

  • Living, working or going to school in damp buildings

  • Spending significant time in buildings where carpets or walls have been saturated with water and not dried promptly

  • Working with moldy materials at work, such as farmers handling moldy hay

How do you prevent black mold exposure?

To prevent exposure, first you must remove any black mold in your living or working space. If you find mold growing on any surfaces or materials, either discard them if possible or clean them with a bleach solution of 1 part bleach to 10 parts water. (Do not mix bleach with other cleaners.)

If carpets, insulation, drywall or other porous surfaces become saturated with water, they should be cleaned and dried within 48 hours to prevent mold growth. If they can’t be dried promptly, it’s best to remove and replace them.

There are also other ways to lower your risk of black mold exposure, including:

  • Lower the humidity in your home. If you live in a humid climate, using air conditioning or a dehumidifier will help reduce the level of humidity in your home. Aim to keep humidity levels between 30 to 50%.

  • Remove carpet from bathrooms and basements, which are more likely to be humid or have a lot of moisture.

  • Improve the ventilation in humid rooms of your home. Fans that remove moisture from bathrooms and kitchens will help lower humidity and help prevent mold growth.

  • Clean bathroom tiles and other damp areas regularly.

  • Fix leaks in roofs, walls or plumping promptly. 

  • Remove books and newspapers from damp areas, and get rid of them if they become moldy.

  • Wear a mask over your nose and mouth while mowing the lawn or doing other yard work to prevent inhaling mold.

  • Stay indoors on days when airborne mold counts are high.

In some cases, you may need a professional to remove large amounts of mold in your home or work space. If you think you have been exposed to black mold and are having persistent symptoms, see your doctor to discuss your symptoms.

How do doctors diagnose black mold exposure?

Before conducting any diagnostic tests, your doctor will ask you about the symptoms you have been experiencing and for how long they have lasted. It’s important to keep a record of your symptoms and how long you have been having them. Questions your doctor might ask include:

  • What are your symptoms?

  • How long have you been having these symptoms?

  • When or where do you experience the worst symptoms?

  • When or where are your symptoms lessened?

  • Do your symptoms worsen at certain times of the year?

  • Do you have a family history of mold allergies?

  • Do you have frequent exposure to mold?

Currently there is no black mold exposure test available, such as a blood or urine diagnostics, to detect exposure to black mold or any other kind of mold. However, your doctor may be able to test for a mold allergy using a blood test or skin prick test.

Skin prick test: During this test, your doctor will apply a diluted mold to your skin with a small prick. If the prick causes a bump, that indicates you have a mold allergy.

Blood test: From a blood sample, a lab can measure antibodies in your bloodstream to detect mold sensitivity.

With the answers to these questions and allergy tests for molds, your doctor should be able to diagnose whether you have an allergy to mold.

What are the potential complications of black mold exposure?

For most people, complications of black mold exposure are no more serious than mild to moderate allergy symptoms. While these symptoms may be annoying, they are not dangerous. For people with asthma, black mold exposure may cause more serious complications, such as wheezing, shortness of breath, or chest tightness. While these are not generally an emergency situation, it’s important to get evaluated by a doctor if symptoms persist.

Black mold has been blamed for acute idiopathic pulmonary hemorrhage among babies, but this link has not been scientifically proven.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Sep 17
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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