Relevance of Inhalational Exposure to Food Allergens
Purpose of Review: This review discusses the inhalational route as a clinically important route of exposure to food allergens.
Recent Findings: In childhood, we have recently demonstrated that food allergens can induce both early and late phase bronchial reactions within blinded, placebo-controlled challenges. Additionally, clinically important levels of food allergens have been measured in environmental air samples.
Summary: It is well known that the ingestion of food allergens frequently causes respiratory symptoms and that the mechanism of death in fatal anaphylaxis is usually profound bronchospasm. The mechanism by which ingested food allergens induce bronchial reactions is unclear. There are many case reports of bronchial reactions to aerosolized food allergens. Within the food industry the problems have been examined more systematically. From such work it is possible to gain an impression of the potential prevalence of the problem. With 10% of adult asthma being occupational and 10% of occupational asthma being induced by aerosolized food, inhalational exposure to food allergens plays a major role in at least 1% of adult asthma. For a patient with co-existent food allergy and asthma it is important that both dietary and environmental avoidance be practised. The similar pathophysiology of allergic and occupational asthma and the ability of inhaled food allergens to cause the latter raises the question as to whether aerosolized food could play a role in the pathogenesis of childhood asthma.

Foods generally behave as allergens when they are eaten or come into contact with the skin. Their ability to become aerosolized and cause bronchial reaction through an inhalational route is less well appreciated. Most severe allergic reactions predominately involve respiratory compromise. In this review, we will look at the problems of respiratory reactions to ingested and inhaled foods.