Mold is a common cause of allergy.  There are thousands of types of molds and yeasts, however, only a small number of molds are widely recognized to cause allergic reactions.

Allergic rhinitis can result when tiny fungal spores, or sometimes pieces of fungi is inhaled.  These small, mold spores also can reach the lungs.  A small number of people experience symptoms of mold allergy when eating certain foods such as cheeses processed with fungi.  Mushrooms, dried fruits, and foods containing yeast, soy sauce, or vinegar will occasionally produce allergy symptoms.

Molds are found wherever there is moisture, oxygen, and a source of the few other chemicals they need.

Where do molds grow?

•    In the fall, mold grows on rotting logs and fallen leaves, especially in moist, shady areas
•    In gardens, mold can be found in compost piles and on certain grasses and weeds
•    Molds can attach to grains such as wheat, oats, barley, and corn, which make farms, grain bins, and silos common places
•    Damp basements and closets in the home
•    Bathrooms, especially shower stalls
•    Places where fresh food is stored
•    Refrigerator drip trays
•    House plants
•    Air conditioners
•    Humidifiers
•    Garbage pails
•    Mattresses
•    Upholstered furniture
•    Old foam rubber pillows
•    Bakeries
•    Breweries
•    Barns
•    Dairies
•    Greenhouses
•    Loggers, mill workers, carpenters, furniture repairers, and upholsterers often work in moldy environments

What molds cause allergic reactions?

•    Alernaria and Cladosporium (Hormodendrum) are the molds most commonly found both indoors and outdoors in the United States
•    Aspergillus, Penicillium, Helminthosporium, Epicoccum, Fusarium, Mucor, Rhizopus and Aureobasidium (Pullularia) are also common

There is no relationship between a respiratory allergy to the mold Penicillium and an allergy to the drug penicillin, which is made from mold.

Is it helpful to know mold counts?

•    Mold counts probably cannot be used as a constant guide for daily activities

Many common allergenic molds are of the dry spore type and release their spores during dry, windy weather.  Other molds need high humidity, or dew to release their spores.  Rain washes many larger spores out of the air; however, it also causes some smaller spores to be carried into the air.  Dry spore types are usually released during daytime.  Wet spore types are usually released at night.

Other mold-related disorders include:

•    Aspergillus may cause different illnesses.  Fungi may lodge in the airways or a distant part of the lung and grow until they form a compact sphere known as a “fungus ball.”
•    In people with lung damage or serious underlying illnesses, Aspergillus may grasp the opportunity to invade the lungs or the whole body.
•    In some people exposure to these fungi can lead to asthma or to a lung disease similar to severe inflammatory asthma called “allergic bronchopulmonary aspergillosis.”  This condition occurs in a small number of people with asthma.  Corticosteroid drugs usually treat this reaction effectively.  Immunotherapy (allergy shots) is not helpful.

Source:  National Institute of Allergy and Infectious Diseases