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Black mold is a fungus that may cause your immune system to react. Common symptoms include sneezing, coughing, congestion and eye irritation. It rarely causes serious illness or death but may worsen asthma symptoms. You can’t cure a black mold allergy, but a healthcare provider can diagnose it and help treat your symptoms.
Black mold is a type of fungus that looks dark green or black. There are many kinds of black mold, but when most people refer to it, they’re referring to Stachybotrys chartarum (S. chartarum). It grows and spreads on materials that contain a lot of cellulose, including paper products, wood products and drywall. Cellulose is a fiber in fruits, vegetables and other plants. It’s part of the cell wall.
Black mold needs warm temperatures and moisture to grow and spread. It commonly appears in damp or water-damaged areas of your home, such as basements, showers and windows.
For most people, black mold won’t make you very sick or kill you.
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If you have mold allergies, black mold can make you sick.
Black mold produces spores, which can enter the air. Molds also produce microbial volatile organic compounds (mVOCs), which create an unpleasant “moldy” or musty smell. If you have allergies, you can have allergy symptoms from the spores or mVOCs. Allergy symptoms occur when your immune system is hypersensitive to these spores. This results in your immune system releasing chemicals that cause inflammation in your nose, eyes and lungs. Even if you don’t have allergies, you can still experience irritation from mVOCs.
If you have a weakened (compromised) immune system — for example, from immunodeficiency disorders or medications that suppress your immune system — black mold exposure can also cause a fungal infection (mycosis) in your airways or other parts of your body.
All types of mold can affect people who have mold allergies. However, black mold isn’t any more dangerous than any other types of mold.
How quickly black mold affects you depends on whether you have any allergies or sensitivities to it. Your body is unique, and how you react to black mold may differ from how others respond to it.
If you’re allergic to black mold, you may have symptoms immediately after spores come in contact with your body.
If you’re not allergic to black mold, you may not have any symptoms, or your symptoms may not appear for a long time.
Black mold can irritate anyone, even if you don’t have mold allergies. However, the symptoms are usually worse if you:
Breathing in black mold spores causes an allergic reaction if you have black mold allergies. An allergic reaction is your body’s response to an allergen.
If you have black mold allergies, your body responds to your first encounter with black mold spores by creating immunoglobulin E (IgE). IgE are antibodies your immune system makes. Your body makes different types of IgE, which target specific kinds of allergens, including black mold. IgE antibodies bind to mast cells (histamine-containing cells) in your mucus membranes, skin, gastrointestinal (GI) tract and airways. After your first exposure, the mast cells are now sensitive to black mold allergens.
The next time the mast cells encounter black mold spores, the mast cells release histamine and other chemicals. Histamine is what causes your immediate allergy symptoms. Your symptoms develop very fast — usually within seconds or minutes. The other chemicals can cause ongoing inflammation.
The most common symptoms of black mold exposure include:
Black mold exposure can also trigger or worsen asthma symptoms, including:
No, there isn’t any evidence that black mold exposure causes acute idiopathic pulmonary hemorrhage (AIPH) in infants. AIPH is a type of hemorrhage in infants in which blood leaks from a blood vessel around the airways into the lungs.
There isn’t any evidence that black mold exposure causes other serious health issues such as memory loss, nosebleeds, body aches or mood disorders.
Black mold grows naturally in the environment. You can find it in most places in nature. You can also find it in areas of your home that have the proper conditions for it to grow, such as a bathroom, basement, laundry room or areas with water leaks. In order to grow and spread, it needs:
Microscopic black mold spores are everywhere in our environment. They can enter your home through open windows, doors and vents. They can also latch onto your clothing or pets when you go outdoors. Once they find an area with the proper conditions, they grow and spread on surfaces until they become visible to the naked eye.
An allergist is a healthcare provider who specializes in allergies. They can help you diagnose a black mold allergy through tests.
A healthcare provider may use different allergy tests to help diagnose your black mold allergy based on your symptoms and suspected allergens. These tests may include the following:
This test exposes your body to small amounts of black mold allergens.
Your healthcare provider will first clean a test area of your skin with alcohol. The test area is usually on your forearm or upper back.
Your allergist will use a thin needle (lancet) to prick your skin with black mold allergens. The lancet won’t go deep into your skin. You’ll only feel a tiny pinch, and you won’t bleed.
Allergic reactions typically occur within 15 minutes of exposure to the possible black mold allergens. Reactions may include skin discoloration (red, gray or white) or raised, round spots called wheals that look like mosquito bites.
Your allergist will measure the size of your wheal.
A skin prick test takes less than an hour.
During a blood test, your healthcare provider will use a thin needle (slightly smaller than the size of a standard earring post) to withdraw a small amount of blood from a vein in your arm. The blood sample goes to a laboratory. The lab test measures the amount of IgE in your blood that binds to black mold.
It may take a week or longer to get the results from a blood test sent to a lab.
Blood tests can have a higher rate of false-positive results. A false-positive result is when a test says you have a specific allergy, but you don’t.
You can’t get rid of black mold allergies. However, you can help treat your symptoms.
The first step in treating a black mold allergy is to avoid it. If you have a water leak, make sure someone repairs it as soon as possible. If you have contaminated materials, throw them away.
The next step is to rinse your sinuses or get medications that help treat your symptoms. These treatments may include:
Finally, if you still have black mold allergy symptoms after taking medications, a provider may recommend allergy shots (immunotherapy).
Yes and no. Air purifiers help remove black mold spores from the air. However, they can’t remove mold that’s actively growing on surfaces.
If you have mold in your home, it’s difficult to remove. If you try to remove it yourself, it can spread through the air (aerosolize) and affect other areas of your home. It’s a good idea to first fix any water leaks. Then, run a high-efficiency particulate air (HEPA) filter to help remove spores from the air and seal off the room. Finally, contact professionals who specialize in mold removal.
There’s no proof that mold toxins cause diseases in people, so you don’t need to detox after mold exposure. The best way to feel better if you have black mold allergy symptoms is to get out of the moldy environment and avoid any continued exposure. You can also take prescription or over-the-counter (OTC) medications to help relieve your symptoms.
You can’t prevent a black mold allergy. However, the following tips can help prevent black mold from growing:
Mold spores are everywhere, so you can’t avoid them. If you spend time around moldy areas, you’re going to have black mold allergy symptoms. However, you can reduce your exposure to high levels of mold spores by making sure your home doesn’t have any areas that encourage black mold growth. If you can reduce your exposure, medications can help reduce your symptoms. With immunotherapy, you may not have any allergic reactions after black mold exposure (asymptomatic state).
If you suspect you have a black mold allergy, reach out to your healthcare provider or an allergist for a diagnosis.
See a healthcare provider if you have black mold allergy symptoms, especially if they affect your day-to-day quality of life.
“Mildew” is an imprecise term. Some people use it to refer to the surface stains that molds cause, while others use it to refer to specific types of mold.
A note from Cleveland Clinic
Black mold is a fungus that grows in warm, damp areas. Its spores may mistakenly trigger an allergic reaction in your immune system. An allergic reaction to black mold may cause various symptoms, including coughing, sneezing, congestion and irritated eyes. However, it rarely makes people very sick.
If you have black mold allergy symptoms, contact a healthcare provider. They can conduct tests to confirm a black mold allergy. They can also recommend medications that prevent symptoms.
Last reviewed by a Cleveland Clinic medical professional on 03/31/2023.
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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy