Mold Allergy

What Is a Mold Allergy?

If you have an allergy that occurs over several seasons, you may be allergic to the spores of molds or other fungi. Molds live everywhere. Upsetting a mold source can send the spores into the air.

Mold and mildew are fungi. They are different from plants or animals in how they reproduce and grow. The “seeds,” called spores, travel through the air. Some spores spread in dry, windy weather. Others spread with the fog or dew when humidity is high.

Inhaling the spores causes allergic reactions in some people. Allergic symptoms from fungus spores are most common from July to early fall. But fungi grow in many places, both indoors and outside, so allergic reactions can occur year round.

Although there are many types of molds, only a few dozen cause allergic reactions. Many molds grow on rotting logs and fallen leaves, in compost piles and on grasses and grains. Unlike pollens, molds do not die with the first killing frost. Most outdoor molds become inactive during the winter. In the spring they grow on plants killed by the cold. Indoors, fungi grow in damp areas. They can often be found in the bathroom, kitchen or basement.

What Are the Symptoms of a Mold Allergy?

The symptoms of mold allergy are very similar to the symptoms of other allergies, such as sneezing, itching, runny nose, congestion and dry, scaling skin.

  • Outdoor molds may cause allergy symptoms in summer and fall (or year-round in some climates)
  • Indoor molds may cause allergy symptoms year-round

Mold spores get into your nose and cause hay fever symptoms. They also can reach the lungs and trigger asthma. A chemical released by allergy cells in the nose and or lungs causes the symptoms. Sometimes the reaction happens right away. Sometimes a mold allergy can cause delayed symptoms, leading to nasal congestion or worsening asthma over time. Symptoms often get worse in a damp or moldy room like a basement. This may mean you have a mold allergy.

Mold can trigger allergies and asthma

Rarely, some patients can have a more serious illness called allergic bronchopulmonary aspergillosis. In this condition, there is both an allergic and an inflammatory response to the mold. Symptoms may include severe wheezing, coughing and shortness of breath, much like asthma.

Food fungi, like mushrooms, dried fruit, or foods containing yeast, vinegar or soy sauce, usually don’t cause allergy symptoms of the nose, eyes and lungs. It is more likely that reactions to food fungi are caused by the food's direct effect on blood vessels. For example, fermented foods (like wine) may naturally contain a substance known as histamine. Histamine is also a chemical your allergy cells release during an allergic reaction. Foods that contain histamines can trigger allergy-like responses when you consume them.

How Do Doctors Diagnose Mold Allergy?

To diagnose an allergy to mold or fungi, the doctor will take a complete medical history. If they suspect a mold allergy, the doctor often will do skin tests or allergen specific IgE blood tests. Extracts of different types of fungi may be used to scratch or prick the skin. If there is no reaction, then you probably don’t have an allergy. The doctor uses the patient's medical history, the skin testing results and the physical exam to diagnose a mold allergy.

How Can I Prevent an Allergic Reaction to Mold?

There is no cure for allergies. But you can reduce your allergy symptoms by avoiding contact with the mold spores. Several measures will help:

Reduce Your Exposure to Mold Spores Outside

  • Limit your outdoor activities when mold counts are high. This will lessen the amount of mold spores you inhale and your symptoms.
  • Wear a dust mask when cutting grass, digging around plants, picking up leaves and disturbing other plant materials.

Reduce Your Exposure to Mold Spores Inside

  • Use central air conditioning with a HEPA filter attachment. This can help trap mold spores from your entire home. Freestanding air cleaners only filter air in a limited area. Avoid devices that treat air with heat, electrostatic ions or ozone.
  • Lower your indoor humidity. No air cleaners will help if excess moisture remains. If indoor humidity is above 50 percent, fungi will thrive. A hygrometer is a tool used to measure humidity. The goal is to keep humidity below 45 percent, but below 35 percent is better.

    If you have to use a humidifier, clean the fluid reservoir at least twice a week to prevent mold growth. Air conditioners and dehumidifiers can also be a source of mold.
  • Prevent mold and mildew build up inside the home. Pay close attention to mold in bathrooms, basements and laundry areas. Be aggressive about reducing dampness.

how to prevent mold and mildew buildup in your home

To Reduce Mold in Your Bathrooms:

  • Use an exhaust fan or open a window in the bathroom during baths and showers.
  • Remove bathroom carpeting from places where it can get wet.
  • Scour sinks and tubs at least monthly. Fungi thrive on soap and other films that coat tiles and grout.
  • Quickly repair any plumbing leaks.

To Reduce Mold in Your Kitchen:

  • Clean garbage pails frequently.
  • Clean refrigerator door gaskets and drip pans.
  • Quickly repair any plumbing leaks.
  • Use an exhaust fan when you are cooking or washing dishes.

To Reduce Mold in Your Laundry Area:

  • Remove clothes from washing machine promptly.
  • If you have a front-loading washing machine, clean the rubber seal and inside of the door. Leave the door cracked open when the machine is not in use.
  • Don’t leave wet, damp clothes sitting around.
  • Make sure your laundry area has good air circulation.

To Reduce Mold in Your Bedrooms:

  • Polyurethane and rubber foams seem especially prone to fungus invasion. Use plastic covers on bedding made from these foams.
  • Throw away or recycle old books, newspapers, clothing or bedding.
  • Check windows for condensation (water droplets or mist).
  • Improve air flow through your bedroom. If your closet is colder than the rest of your room, leave the closet doors open.

To Reduce Mold in Your Basement:

  • Quickly repair any plumbing leaks.
  • Promote ground water drainage away from a house. Remove leaves and dead vegetation near the foundation and in the rain gutters.

To Reduce Mold in Your Whole House:

  • Use an electric dehumidifier to remove moisture and keep humidity in your house below 45 percent. Drain the dehumidifier regularly and clean the condensation coils and collection bucket.
  • Increase air flow in your home.  Open doors between rooms, move furniture away from walls and use fans if needed.
  • Repair roof leaks and roof gutters. Clean out your gutters to remove leaves and debris. When gutters are full or damaged, it can cause leaking.

What Are the Treatments for Mold Allergy?

In some cases, there may be ways to reduce or remove mold exposure. This may not always be possible and you may need medications.

  • Avoid contact with mold. (See tips above)
  • Take medications for nasal or other allergic symptoms. Antihistamines and nasal steroids are available over the counter without a prescription. If you have allergic asthma, talk to your doctor about which medicines may be best for you. You might also be a candidate for allergy shots. Allergy shots may help reduce symptoms and medications. Learn more about allergy treatments.

Medical Review October 2015.