Fungi (mold) spores are among the most important airborne organic materials that cause respiratory allergies such as hayfever and asthma. About 100,000 species of fungi have been identified, and many of them can cause diseases in humans, animals, and plants.

In contrast with pollen — about which there is considerable data concerning identification in the air and ability to cause allergic symptoms — mold spores are difficult to identify and count in the air, and less is known about their importance as causes of respiratory allergy.

Where Are Molds Found?

Molds can be found in most environments and, unlike pollens, do not have a strictly limited season. Their growth is encouraged by warmth and high humidity, so they are most prevalent during the humid seasons of the year. Molds are found both outdoors and in the home. They are present in outside air unless there is a cover of snow on the ground, and are especially prevalent in shady, damp areas and on decaying leaves or other vegetation. Mold spores produced outside become widely dispersed through the air and can enter the home. Other molds are produced indoors, especially in areas of high humidity such as showers and basements.

What Can Be Done to Decrease Mold Exposure?

Mold-sensitive individuals should avoid exposure to areas of high mold growth, such as basements, compost piles, fallen leaves, cut grass, barns, and wooded areas. A face mask should be worn when such exposures are unavoidable. In the home, it is important to prevent high levels of humidity. Obtain a gauge to measure relative humidity and keep the level below 35%, using air conditioners and dehumidifiers in the summer and avoiding over-humidification in the winter. Excess humidity from showering or cooking should be removed with an exhaust fan. Mold growing in the home can be killed with various products.

Mold Control in the Home

Throughout the House

• Keep humidity low — 30% if possible, but no higher than 50%. Obtain a gauge to measure relative humidity.

• Use an air conditioner or dehumidifier in the summer with windows closed. Dehumidifiers must be emptied of water regularly. Air conditioners should be sprayed at the air intake with a mold-killing spray if they develop a musty odor.

• If using a humidifier in the winter, avoid over-humidification. Wash the humidifier and change the water frequently to prevent mold growth, occasionally cleaning the interior with a dilute bleach solution. Central humidifiers are common sources of mold growth and must be checked and cleaned frequently.

• Very tightly insulated houses prevent the escape of moisture and thus encourage mold growth. Allow adequate ventilation.
Out of Doors

• Avoid cutting grass and raking leaves, or use a face mask if these chores must be done by the allergic individual. Avoid exposure to soil, compost piles, sandboxes, hay, fertilizers, and barns. Prune or cut trees to avoid shading of the home. Eliminate vines.

• Correct drainage problems near the house, as pooled water greatly increases mold formation.

• Avoid camping or walking in the woods where mold growth on rotted logs and other vegetation is high. Some mold spores are spread on dry and windy days, others during rainfall. Limit outdoor exposure at these times.
In the Kitchen

• Use an exhaust fan to remove water vapor when cooking.

• Mold can grow in refrigerators, particularly around the door gaskets. Empty water pans below self-defrosting refrigerators frequently. Remove spoiling foods immediately.

• Garbage containers are a source of mold growth and should be emptied frequently and kept clean.
In the Bathroom

• Use an exhaust fan or open window to remove humidity after showering.

• Wash shower curtains, bathroom tiles, shower stall or tub, toilet tank, and ceiling with mold-killing and mold-prevention solutions. Repair any damaged caulking or grout. Replace the shower curtain when mold growth is noted.

• Do not carpet the bathroom.
In the Basement

• Use a dehumidifier. Correct seepage or flooding problems, and remove any previously flooded carpet. If a dirt floor is present, cover it with a plastic vapor barrier.

• Keep the basement free of dust and remove moldy stored items. Avoid storing unnecessary items likely to harbor molds. Use paint with a mold inhibitor, especially on brick or cinder block walls.

• Allergic individuals should avoid living in basement apartments or dormitories.

Products to Kill Molds

A solution of equal parts household bleach and water will kill mold. Commercially available products such as X-14 contain a similar solution combined with cleaning agents in a spray dispenser.
Mold growth can be prevented by a solution of 1 oz. of 17% Zephiran (available in pharmacies) in 1 gallon of water, or by commercially available Mildew Stop spray.

Medications

Pharmacologic therapy for mold allergy is the same as that for allergies caused by other inhaled allergens such as pollens. These include, but are not limited to, bronchodilators, antihistamines, and corticosteroids. In more severe cases, patients with mold-induced respiratory allergy may be treated with immunotherapy.