Primary and secondary prevention of allergic asthma

The primary prevention of asthma requires environmental strategies aimed at reducing both the development of allergic sensitization and the development of asthma in those who have already become sensitized. The environmental interventions that would seem most promising at the current time are those which address exposure to indoor allergens and maternal smoking because there is consistent evidence of their effects. Several studies have demonstrated the effectiveness of allergen avoidance in preventing asthma and, because of the potential benefits of such interventions, it is important that they continue to be developed to improve both their acceptability and effectiveness. On the other hand, few studies have investigated the feasibility and efficacy of antismoking interventions during pregnancy and it remains important that new interventions are developed that specifically address smoking in this group. Because there is also some evidence that both breastfeeding and dietary factors are important in the aetiology of asthma, limited advice about their role can be given. Given the knowledge of the risk factors for asthma that we now have available, we have a responsibility to recommend preventive and potentially preventive strategies to parents whose children are at high risk for developing this illness.