Ingested foods are important causes of allergic reactions. They may provoke symptoms alone, or they may aggravate those primarily produced by inhaled antigens. The detection of foods responsible for clinical reactions is more difficult than the demonstration of inhalant offenders. Seasonal or massive exposure to inhalant allergens may result in attacks which are evident from the clinical history. Symptoms resulting from continued ingestion of common foods are less easily related to the causal allergens. Both foods and inhalants can cause rhinitis, asthma, urticaria and other manifestations commonly associated with allergic reactions. In addition, less commonly recognized symptoms such as malaise, lassitude and headache, which may occur in inhalant reactions, may also result from food allergy. However, these symptoms alone, especially in the absence of demonstrated inhalant sensitivities, cannot be accepted as evidence of food allergy. Functional or organic disease is more apt to be responsible.
Food allergy may occur at