The Allergic Response
Asthma and allergies often coexist, and the allergic response plays a strong role in childhood asthma. About 70 - 85% of children with asthma also have allergies. Some studies suggest that children who have allergies are also at greater risk for developing asthma as adults. A 2006 study found that children who are allergic to dust mites are three times more likely to later develop asthma than children who were not allergic. Some experts think that giving immunotherapy (“allergy shots”) to children with allergies may help prevent asthma development.
An asthma attack can be induced or aggravated by direct irritants to the lungs. Studies indicate that the more indoor allergens a child is allergic to, the higher the risk for severe asthma. Important irritants or allergens include the following:
- Dust mites, specifically mite feces, which are coated with enzymes that contain a powerful allergen. These are the primary allergens in the home.
- Animal dander. Cats harbor significant allergens, which can even be carried on clothing; dogs usually present fewer problems.
- Molds.
- Cockroaches. Cockroaches are major asthma triggers and may reduce lung function even in people without a history of asthma.
- Pollen. An asthma attack from an allergic response to pollen is more likely to occur during extreme air changes, such as thunderstorms. Major weather changes, such as El Nino, can affect the timing of allergy seasons. For example, in 1998, when the effects of El Nino were very strong, allergy and asthma attacks were markedly increased, and maximum tree pollen counts occurred 2 to 4 weeks earlier and mold counts 2 to 3 months earlier than in the previous year.
- Food allergies. About 8 - 10% of children with asthma also have food allergies. These children also appear to have a high risk for very serious reactions to such foods. In infants and toddlers, allergy to eggs appears to be a major predictor of asthma.
- Fossil Fuels. Certain chemicals may trigger allergic rhinitis. Some experts believe that refined fossil fuels, such as diesel fuel and particularly kerosene, may be important triggers for allergic rhinitis. And, in people who already have allergies or asthma, exposure to such fossil fuels may worsen symptoms.
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