This booklet summarizes what is known about the causes and symptoms of allergic reactions to airborne allergens, how these reactions are diagnosed and treated, and what medical researchers are doing to help people who suffer from these allergies. An allergy is a specific immunologic reaction to a normally harmless substance, one that does not bother most people. Allergic people often are sensitive to more than one substance. Types of allergens that cause allergic reactions include food, dust particles, medicines, insect venom, mold spores, or pollen. Scientists think that people inherit a tendency to be allergic, although not to any specific allergen.
Children are much more likely to develop allergies if their parents have allergies.
Even if only one parent is allergic, a child has a one in four chance of developing allergies. Exposure to allergens at certain times when the body's defenses are lowered or weakened, such as after a viral infection, during puberty, or during pregnancy, seems to contribute to the development of allergies. Asthma may be triggered by allergens and irritants that are common in homes and Work Place.