Molds can be found wherever there is moisture, oxygen, and a source of a few other chemicals. These places include damp basements and closets, bathrooms, places where fresh food is stored, and refrigerator drip trays. When fungal spores are inhaled, a person with a mold allergy might experience symptoms such as allergic rhinitis. Some preventive measures for this type of allergy include using a dehumidifier to maintain relative humidity below 50 percent, regularly checking faucets and pipes for leaks, and removing decaying debris from the yard, roof, and gutters.
There are thousands of types of molds and yeasts in the fungus family. Yeasts are single cells that divide to form clusters. Molds are made of many cells that grow as branching threads called hyphae. Although both can probably cause allergic reactions, only a small number of molds are widely recognized causes of a mold allergy.
The seeds or reproductive pieces of fungi are called spores. Spores differ in size, shape, and color among types of mold. Each spore that germinates can give rise to new mold growth, which, in turn, can produce millions of spores.
When inhaled, tiny fungal spores, or sometimes pieces of fungi, may cause allergic rhinitis. Because they are so small, mold spores also can reach the lungs.
In a small number of people, symptoms of mold allergy may be brought on or worsened by eating certain foods such as cheeses processed with fungi. Occasionally, mushrooms, dried fruits, and foods containing yeast, soy sauce, or vinegar will produce allergy symptoms.
(Click Allergy Symptoms for more information on mold allergy symptoms.)