Allergy & Asthma-Kent H. DeYarman, MD

Topics in Allergy

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Reducing Exposure to Mold Spore Allergens

Allergy to mold, especially a mold known as Alternaria, is a risk factor for developing asthma and can cause nasal, sinus, and eye allergy symptoms. Most exposure to mold spores is from outdoor exposure but some molds such as Penicillium and Aspergillus are found inside buildings. Much less is known about mold allergy and sources of mold exposure than for other allergens such as dust mites, animals, and pollens. Mold growth is highest in warm humid parts of the country (east of the Rockies). The coast has higher mold growth than inland valleys. In the Rogue valley molds are present all year but mold counts are highest in spring and fall when humidity is higher and temperatures are warmer. Measurements of mold in homes can be done but is of limited value as there are no standards available to interpret the meaning of the measurement. In general, if mold counts inside are higher than outside counts, one can conclude that indoor mold contamination is present.


Indoor mold exposure occurs in two ways: through infiltration of mold spores from outside (through open windows, etc) and from mold growth indoors. Reducing mold exposure needs to consider both sources. Avoidance of molds depends on preventing infiltration of molds from outside air into the home and on changing conditions that encourage mold growth indoors (moisture).


Basic measures to reduce mold exposure are listed below. None of these have been scientifically tested.


*Prevent mold spore infiltration into your home by closing doors and windows and by using air conditioning.

*Remove water damage or mold contaminated carpet, furniture, bedding, etc.

*Seal water leaks and ventilate bathrooms and kitchens.

*Dehumidifiers may be needed for damp basements.

*Maintain heating and air conditioning systems.

*Improve ventilation to moist areas with little air movement such as crawl spaces. Commercial electric heat rods can help keep these areas dry.

*High efficiency (HEPA) room air filters can reduce mold exposure. These are available locally and through the internet. There are few reliable comparison studies of HEPA filters. Consumer Reports is an unbiased source and preferred the Honeywell Enviracaire filter. This is available in several different sizes.

*Clean and remove contaminated materials by applying dilute bleach with detergent or commercial products for mold cleaning molds such as Tilex.

*When repainting is needed in damp areas use mildew resistant paint. You may also buy mildewcides that may be added to paint.

Most people with mold allergies only have problems with airborne mold spores. Mold in foods (cheeses, beer, wine, baked goods, etc) are not usually a problem. If you suspect these foods do bother you, elimination of a food for 1 week followed by a challenge of a normal serving of the food may clarify this question.