The risk of allergy in asthma.

The prevalence of atopy among asthmatics is more than 70 per cent. Atopy is more prevalent among older children and young asthmatic adults. It is inherited, but the pattern of inheritance is not well defined. Increase in total IgE is one manifestation of atopy, and increase in IgE in early infancy is a predictor of atopic illness, including asthma. Sensitization to allergens and repeated exposure is one of the triggers of developing asthma in atopic patients. Allergy even without asthma (allergic rhinitis) is associated with an increase in bronchial reactivity. Allergy is a risk factor in occupational asthma and in exercise induced asthma. In fact, many non-asthmatic allergic rhinitis patients wheeze with exercise. Allergen avoidance and environmental control may contribute to the well-being of many asthmatics. Allergy hyposensitization (immunotherapy) may help control asthma in allergic patients.