The role of allergens in asthma.

The National Asthma Education and Prevention Program Expert Panel guidelines for the management of asthma recommend that patients who require daily asthma medications have allergy testing for perennial indoor allergens and that, when triggers are found, exposure to allergens and pollutants be controlled through avoidance and abatement. For patients whose symptoms are not controlled adequately with these interventions and who are candidates for immunotherapy, the guidelines recommend referral to an allergist. However, the data supporting these recommendations are not consistent. Although there is evidence that simple allergen avoidance measures are ineffective, there is good evidence for the effectiveness of a comprehensive approach based on known sensitization. Thus, allergen avoidance may include removal of pets, use of high-efficiency particulate air filtration and vacuum cleaners, use of allergen-impermeable mattress and pillow covers, cockroach extermination, smoking cessation, and measures to control mold growth in the home. All allergen-specific treatment is dependent on defining sensitization. This can be achieved through serum assays of immunoglobulin E antibodies or skin tests with aeroallergens. Information on sensitization can be used to educate patients about the role of allergens in their symptoms, to provide avoidance advice, or to design immunotherapy.