Is primary prevention of asthma possible?

Two major factors are critical to the development of asthma: the individual's genetic background and the environment. The gene for asthma has not yet been identified. Thus, environmental factors appear to be the critical factors that can be controlled. Exposure to specific allergens is important. Ingestants may be the earliest initiating trigger for 'turn on' of allergy. Subsequently, sensitization to indoor inhalants becomes important in asthma. Among pollutants, environmental tobacco smoke (ETS) is most important. Finally, infections play a role in the development of asthma. Approaches to primary prevention include potential novel techniques such as vaccines or immunization. Dietary intervention appears to be important for atopic dermatitis but less so for asthma. Nevertheless, breastfeeding is successful in decreasing respiratory illness and should be encouraged. In terms of allergen avoidance, avoidance of indoor allergens, particularly house dust mite, cat and cockroach, have the greatest potential for benefit. Exposure to ETS in early life must be avoided. Asthma is a multifactorial disease, and complex interventions are likely to be required to decrease prevalence of this increasingly common disease.