Allergenic and Pathogenic Molds
Allergenic Molds
Along with pollens from trees, grasses, and weeds, molds are an important cause of seasonal allergic rhinitis. People allergic to molds may have symptoms from spring to late fall. The mold season often peaks from July to late summer. Unlike pollens, molds may persist after the first killing frost. Some can grow at subfreezing temperatures, but most become dormant. Snow cover lowers the outdoor mold count dramatically but does not kill mold. After the spring thaw, molds thrive on the vegetation that has been killed by the winter cold.
In the warmest areas of the United States, however, molds thrive all year and can cause year-round (perennial) allergic problems. In addition, molds growing indoors can cause perennial allergic rhinitis even in the coldest climates.
Pathogenic Molds
Pathogenic molds usually produce some type of infection. A normal, healthy individual can probably resist infection by these organisms regardless of dose, however, pathogenic molds can cause serious health effects in persons with suppressed, underdeveloped, or compromised immune systems. In some cases, high exposure may cause hypersensitivity pneumonitis (an acute response to exposure to an organism). People with compromised immune systems would be, infants and small children whose immune systems are not fully developed, elderly people whose immune systems are essentially worn out, and anyone exposed to AIDS, chemotherapy, pneumonia, bronchitis, and other respiratory infections.
Allergies to Dust Mite
Dust mites are microscopic animals, too small to be seen with the naked eye. The droppings and decaying bodies of dust mites are important allergens. These dust mites live in mattresses, pillows, bedding, carpets, fabric-covered furniture, old clothing and soft stuffed toys. They feed on human skin scales. Dust mites are most common in humid climates. They don't survive when the humidity is below 40-50%. If droppings of dust mites are inhaled or come in contact with the skin, they may cause allergy, asthma and/or eczema symptoms.
Allergies to Animals
Animal dander (dead skin that is continually shed), urine and saliva can cause an allergic reaction. Exposure to these allergens, especially breathing in particles which include dander, cause the allergic reaction to animals. Feathery or furry animals such as cats, dogs, birds, rodents (hamsters, gerbils, mice etc.) can cause allergy symptoms. Unfortunately, there is no such thing as a "hypo-allergenic" cat or dog, and short-haired breeds are no less of a problem than animals with long hair. Exposure to other warm-blooded animals such as livestock, or to products made with feathers or down, may also cause allergy symptoms. If you do not own a feathered or furry pet, do not get one because you can develop allergies with repeated exposure.
Environmental Controls
Once an allergy has been identified, the next step is to decrease or eliminate exposure to the allergen. This is called environmental control. Evidence shows that allergy and asthma symptoms may improve over time, if the recommended environmental controls changes are made. Many of the changes are for the entire home. The bedroom is the most important, because the bedroom is where people usually spend 1/3 to 1/2 of their time.