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Mold Allergies: Symptoms, Diagnosis & Treatment

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 pollen, 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.

Symptoms of a Mold Allergies

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.

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.

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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

#1 – 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.

#2 – 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.

#3 – 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.


About Patrick Donahue, MD

Dr. Patrick Donahue is the Medical Director for WakeMed Physician Practices – Urgent Care.

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