Mold Allergy

An allergy is an abnormal reaction by your immune system to common substances (allergens), like mold, that don’t affect most people. Molds are a type of fungus. They exist almost everywhere in the world. The molds that grow inside our homes prefer dark, damp places, like basements or crawl spaces. They can be harmful to people who have mold allergies.

Mold allergies are common — one study estimates between 3 and 10 out of every 100 people have them. There are a lot of different types of molds. It’s possible for only certain types of mold to cause you to have an allergic reaction.

Are there different types of mold allergies?

Yes. Many different types of molds can cause allergies. Some common types include:

• Alternaria
• Aspergillus
• Cladosporium
• Penicillium

There are also molds that can cause illnesses in people with weakened immune systems, like black mold or other molds.

What are the symptoms of being allergic to mold?

Mold allergy symptoms are a lot like other types of respiratory allergies that cause hay fever-like symptoms. They may include:

• Coughing
• Itchy or watery eyes
• Itchy throat
• Nasal congestion
• Runny nose
• Sneezing
• Wheezing

If you have asthma, mold allergies can trigger an asthma attack.

Mold allergy causes

Molds produce spores. Spores are tiny cells that help molds grow and spread. If your immune system is sensitive to mold spores, it produces immunoglobulin E (IgE). IgE is an antibody that helps find the allergens in your body. They help remove the allergens by taking them to the mast cell (allergy cell), where the allergens attach to a special receptor. The receptor helps send and receive signals in your body. It tells the allergy cell to release histamine and other allergy chemicals, which is what causes allergy symptoms.

As you come across mold spores over time, your immune system sees the spores as something it must get rid of. It creates bigger reactions to protect you.

Risk factors

Molds don’t bother most people unless they have allergies or a weakened immune system. Mold smells can bother people. But they really shouldn’t cause any major issues.

You’re at a greater risk of developing an allergy to mold if you have:

• A personal or biological family history of allergies
• A respiratory condition like asthma

Can living in a house with mold make you sick?

Yes. Long-term exposure to mold can increase your risk of developing an allergy. For example, a humid house or a building with poor ventilation is an ideal environment for mold to grow.

How doctors diagnose mold allergies

A healthcare provider will review your medical history, ask about your symptoms and perform a physical exam. They may recommend tests to confirm their diagnosis. They may also refer you to an allergist.

Tests that are used

Healthcare providers may recommend the following tests to diagnose mold allergies:

• Allergy blood tests: A provider will remove a small amount of blood, usually from a vein in your arm, and test it for IgE against molds. You may have mold allergies if you have high levels of immunoglobulin E antibodies in your blood sample.
• Skin prick (scratch) test: A provider will place droplets of mold allergens on your skin. Then, they’ll scratch your skin near the allergens with a thin needle and look for reactions. Reactions may include itching, discoloration or swelling.

How do you treat a mold allergy?

You can’t cure mold allergies. But one of the most important ways to manage a mold allergy is to avoid mold. This includes avoiding environments in which mold grows easily, like damp places or piles of wet leaves.

Medications can help relieve your symptoms. These may include:

• Antihistamine pills that you take with water
• Over-the-counter nasal steroids
• Nasal antihistamine sprays that you breathe in through your nose

If you have asthma, a healthcare provider may suggest medications such as inhaled corticosteroids.

A provider may also suggest allergy shots (immunotherapy). Each time you get an allergy shot, your body responds by lowering your sensitivity to the allergen. It may take several months before your symptoms start to improve.

When should I see my healthcare provider?

If you have allergy symptoms and you think mold is the cause, call a healthcare provider. They can help treat your symptoms and may recommend allergy testing to make an official diagnosis.

You may wish to ask the following questions during your appointment:

• What mold(s) am I allergic to?
• Do you recommend allergy medications?
• Should I take allergy medications every day or only when I develop symptoms?
• Are there any side effects to allergy medications?
• How do I know when I have mold allergy symptoms or cold and flu symptoms?
• Should I see an allergist?

Contact a provider if you have asthma or other breathing problems and suspect a mold allergy. Call 911 (or your local emergency service number) or go to an emergency room right away if you have severe breathing problems.

What can I expect if I have mold allergies?

There’s no cure for mold allergies. But you can help manage your reactions by avoiding molds and taking medications that a healthcare provider suggests.

Can mold allergies be prevented?

No, you can’t prevent allergies. But you can take steps to avoid and remove mold. These include:

• Clean up mold immediately. You can use household cleaners or a solution of 1 cup of bleach in 1 gallon of water. It’s a good idea to wear protective clothing, including gloves and a respirator or N95 (KN95) mask.
• Control moisture in your home. Make sure your home is properly ventilated (like running a fan in your bathroom) and repair any leaks in your roof, walls or pipes immediately. You can also run a dehumidifier in your basement.
• Stay safe outside. If you have a yard, try to keep it free of piles of damp and decaying leaves or wood. It’s also a good idea to check outdoor mold counts. Stay indoors if mold counts are high.
• Throw away wet carpets, rugs or other textiles that weren’t dried quickly. You should also toss other absorbent materials in which you can’t completely remove mold, like ceiling tiles.

In some cases, it’s a good idea to call a professional. For example, if you have severe mold allergies or you have a contaminated water leak, like sewage.