Allergen avoidance.

The systematic avoidance of indoor allergens by modification of houses, furnishings, or hygiene practices has long been advocated to reduce both the incidence of allergic diseases in at-risk infants and exacerbations or symptoms in those previously sensitized with such a disease. However, such advocacy is now under challenge, due to both a lack of evidence of clinical efficacy of avoidance measures and rapidly changing models of disease causation and pathology. This article reviews the current dilemmas in understanding the complexity of allergen sources, disease risks, nature of bioaerosol exposure, and the inadequacies of many available methods.