Primary and secondary prevention of allergic sensitization

Allergen avoidance as primary prevention: con

There has been a dramatic increase in the prevalence of atopic diseases, such as atopic dermatitis, food allergy, allergic rhinitis, and allergic asthma. Because environmental factors such as early allergen exposure to nutritional and inhalant allergens have been suspected as potential environmental factors favoring the development of allergic diseases and asthma, primary prevention studies have begun to investigate the effect on sensitization and wheezing. Designs of the studies are different and, therefore, are not completely comparable. Although no clear primary prevention study is available for pets, mite allergen avoidance during infancy can achieve a reduction of specific sensitization and, in some studies, can also produce a slight effect on respiratory symptoms.

Allergic rhinoconjunctivitis: epidemiology

Allergic rhinoconjunctivitis has been studied much less frequently than asthma using epidemiologic approaches. Population-based studies are difficult to conduct because of misclassification arising from the reliance on self-reported questionnaires that use terms such as allergic rhinitis or hay fever to establish the diagnosis. In addition, many epidemiologic studies focus on diagnostic skin testing or allergen-specific IgE antibodies (RASTs) as an objective outcome to assess for hay fever. These techniques are helpful but not perfect measures for predicting hay fever outcomes in epidemiologic studies. It is generally accepted, however, that allergic rhinoconjunctivitis is one of the most common of chronic diseases and is the most common atopic disorder. This article reviews the definition of allergic rhinoconjunctivitis, the epidemiology of this disorder from infancy into adulthood, and environmental risk factors for development of sensitization to certain allergens.