Mold Allergy


For many people, exposure to mold causes no issues. But some people have allergic reactions to mold. The National Institutes of Health estimates that about 3-10% of people have a mold allergy.

What is an allergy to mold?

Molds are microscopic organisms called fungi, found virtually everywhere, indoors, and out. Mold grows on plants, foods, wood, drywall, fabrics, and soils. Molds reproduce through spores spread by water, insects or air.

Mold spores are so tiny and lightweight they can float through the air like pollen. Given how small the spores are, they are very easy to breathe in, which may cause an allergic reaction.

An allergy to mold is really a mold spore allergy. A mold allergy is when your immune system overreacts to breathing in mold spores, creating mold allergy symptoms.

What are common types of molds that cause allergies?

While there are 100,000 different types of molds, not all cause allergy symptoms. Some of the most common mold that result in allergies include: alternaria, aspergillus, cladosporium, and penicillium.

An allergy to aspergillus can be particularly problematic for people with chronic lung diseases. There is a rare condition known as allergic bronchopulmonary aspergillosis or ABPA which is caused by a hypersensitivity to aspergillus. ABPA affects approximately 1-2% of people with asthma.

What are mold allergy symptoms?

When inhaled, symptoms of mold allergy include:

  • nasal and sinus symptoms – runny nose, nasal congestion, and sneezing (also known as allergic rhinitis – mold is a type of perennial allergic rhinitis)
  • sore throat
  • watery or burning eyes
  • dry cough
  • shortness of breath
  • irritation of the nose, throat or even skin

What about mold and asthma?

Mold spores are harmful to people with asthma. The small size of mold spores allows them to pass more easily into the lower airways, where they can trigger an asthma attack. Mold spores may also interact with other outdoor allergens and air pollution. This can increase the asthma risk from those substances.

In addition to mold allergy, people also can have an irritant response to some of the volatile chemicals that molds release into the air.

How to diagnose a mold allergy?

To test for a mold allergy, the doctor will take a comprehensive medical history and physical examination. The doctor may ask you about your symptoms and when they occur. Mold allergy tests include:

  • Skin prick tests – Droplets of mold allergens are placed on the skin surface with tiny punctures. Raised bumps (about the size of a mosquito bite) strongly indicate an allergy to that substance.
  • Blood tests – Chemical testing detects Immunoglobulin E (IgE) antibodies circulating in your blood that are directed at specific allergens. Lab results may take days. A blood sample is sent to a medical laboratory, where it can be tested for evidence of sensitivity to specific types of molds.

The doctor will put together all the evidence – test results, your personal and family health history, home and work environments, activities that might expose you to allergens, a physical exam of your eyes, ears, nose and lungs – before reaching a diagnosis.

Can you have an allergy to indoor and outdoor mold?

Yes, you can have an indoor mold allergy and outdoor mold allergy. If you are allergic to mold, you will need to learn where it grows and how to avoid it.

Outdoor mold

Outdoor mold grows in dark, damp places and is found under fallen leaves and in rotting vegetation in gardens. The peak season for mold differs in different parts of the country:

  • Northern United States: Growth begins after the first spring thaw and peaks in late summer and fall
  • Southern United States: Year-round growth
  • Western United States: Year-round growth

Indoor mold

Indoor mold can grow on any organic surface and is found in damp areas such as:

  • basements
  • attics
  • under-sink cabinets
  • refrigerators
  • garbage containers
  • washing machines and clothes dryers
  • upholstery and house plants
  • dusty and musty old books, magazines and newspapers
  • damp window moldings and sills
  • shower stalls and shower curtains

A leak in a roof can cause mold to grow in insulation, ceilings, floors, or even on walls.

Mold can become a significant problem if it remains undiscovered or unaddressed. Allergy symptoms can occur when mold is inhaled.

What can you do if you’re exposed to mold?

Avoiding exposure to mold is the ultimate goal, but it is not always possible. For example, perhaps you had a plumbing leak and found mold growth as you were fixing the leak. Or maybe your roof was leaking and you found mold behind your bedroom walls as you searched for the source of the leak.

You probably inhaled mold spores or you may have lingering mold on your body. Here are some things you can do to reduce your risk of mold allergy symptoms:

  • Get rid of any contaminated materials (carpets, drywall, insulation, etc.)
  • Wash materials that you used, such as bedding or towels.
  • Discard your mask (if worn).
  • Remove clothing and wash in hot water.
  • Rinse your nose with saline.
  • Take a shower to wash away mold.
Photo of woman looking at mold on a wall

How do you limit mold exposure?

Let’s face it, you cannot altogether eliminate mold exposure. Mold is all around us. So, the focus should be on limiting the exposure.

Here are some techniques for reducing your exposure to mold both inside and outside:

Reducing mold inside your home

To reduce mold in your home, eliminate or reduce the conditions they need to grow:

  • moisture – look for areas where excess moisture remains – bathrooms and kitchens can be a common source. A dehumidifier may be helpful to reduce indoor humidity during certain times of year. Make sure all doors and windows have good seals.
  • darkness – look in dark places for mold. Limit moisture in these areas as much as possible.
  • poor ventilation – in places with poor ventilation (such as bathrooms) utilize fans.

Other tips that may limit mold in your home:

  • Make sure your dryers and stoves have vents outside
  • Have your heating, ventilation, and air conditioning (HVAC) systems professionally serviced routinely, with duct cleaning.
  • Use a high efficiency particulate air (HEPA) filter on vacuums.
  • Fix leaks promptly – faucets, pipes, windows, roofs, etc.

If you experience significant mold damage from a flood, it is very important to clean and remove the mold as soon as possible so that health problems don’t develop. If household items are soaked, they should be cleaned, dried out or thrown out. A water-logged couch really can’t be cleaned, so that should be thrown out. All carpeting and draperies should be thrown out as well.

How can you remove mold?

Mold is often difficult to remove in the home. It can even lurk inside walls. It’s best if someone other than the person with the mold allergy works to remove the mold.

When looking for mold, wear a dust mask. Then, identify the source of the excess moisture that is allowing the mole to grow and fix the source if you can. Remove any carpet or drywall that has had mold growing on it. If the mold is extensive, you may need to hire a mold remediation contractor.

In some cases, you can remove visible mold and mildew with a household bleach solution or non-toxic mix of 1 tablespoon baking soda, 2 tablespoons white vinegar and 1 quart water.

Following cleaning, a dehumidifier is often useful in not allowing mold to regrow.

Reducing mold exposure outdoors

Outdoor molds grow on leaves, trees and rotting wood. Keeping your yard clean and free of leaves and rotting wood may help. Keep your rain gutters free of leaves and other debris can both help limit mold growth and prevent excess moisture from pooling.

While ridding the outdoors of mold entirely isn’t possible, you can reduce your exposure by keeping windows closed and limiting outdoor activities when mold levels are high. Many local weather reports list mold counts along with pollution levels. Airborne molds often reach peak levels on dry, windy days when breezes kick up spores growing in moist areas.

What foods should you avoid if you have a mold allergy?

Anyone that has left food in the back of the fridge or the produce drawer too long knows that sometimes mold can grow on food. Avoid eating anything contaminated with mold. You can prevent mold growth by cleaning out your refrigerator routinely and discarding foods past their prime.

There have been a few cases of certain foods known to cause cross-reactivity. In these cases, the person has a respiratory allergy to a certain mold, but when they eat a food contaminated with that mold, they develop food allergy symptoms – maybe even anaphylaxis.

One specific case of cross-reactivity is called Alternaria-spinach syndrome. Alternaria-alternata is a mold commonly associated with allergy symptoms. Spinach can sometimes be contaminated with Alternaria, and cause food allergy symptoms when ingested. Other foods that have been documented to cause this include mushrooms, a vegetarian “meat” product called Quorn (made from fungi), a pancake mix contaminated with mold, and contaminated bee pollen supplements. There was also a case of a person who developed anaphylaxis after eating a food containing a yeast preparation that contained fungi (mold).

There is not a lot of literature on how common mold-allergic people develop reactions when eating certain foods, but cases have been reported, so be cautious.

How do you treat a mold allergy?

Mold allergy treatments include over-the-counter antihistamines, decongestants and intranasal corticosteroids. These common allergy medications can relieve symptoms of runny nose, congestion and itchy and watery eyes.

It may be best to take these medications in advance of when you will be around mold spores. Before starting any medication, speak with your doctor or allergist.

If you have allergic asthma affected by mold, use your quick-relief albuterol inhaler at the first sign of symptoms.

One of the best “treatments” for any allergy is prevention. Limit your exposure to mold and avoid anything known to trigger symptoms. If avoidance is not possible, discuss treatment options with your doctor or allergist.

You may want to wear a mask when you know you’re going to be around mold. This will help prevent you from breathing in mold spores. If you are exposed to mold, you can remove them by rinsing your nose with a saline spray or taking a shower.

Immunotherapy, also called allergy shots, is designed to make your body less reactive to an allergen over time. It comes in the form of either shots or sublingual immunotherapy (SLIT). Immunotherapy is available for certain types of molds, according to the American College of Allergy, Asthma & Immunology (ACAAI). Talk with an allergist for more information.

How do you get rid of mold in your body?

You may be asking, “How do you know if mold is making you sick?” or “How do you know if there’s mold in your body?” There is no special test to look for mold in your body and there are no specific health conditions caused by mold itself. There are no special remedies or methods to “detox” from mold. Be wary of mold misinformation.

We do know that mold can worsen both allergy and asthma symptoms. In rare cases, mold can also lead to infections, but that is normally in people with compromised immune systems. If your allergy or asthma symptoms are worsening or if you are concerned that mold is making you sick, make an appointment with your doctor.

Are there other conditions that can look like or complicate allergies

There are other types of conditions that can mimic allergies, but are different than an IgE-mediated allergy. The symptoms, diagnosis and treatment can vary depending upon the condition. Here are some of them.

Food-related conditions that can have symptoms similar to food allergies include:

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