Food allergic patients with asthma run a higher risk of developing anaphylaxis than other food allergic patients. The true prevalence is unknown. In adults the figure is somewhat lower. Food allergy is an immunological response to food, while food intolerance is a non-immunological response. Food allergy may be identified by an IgE determination, but there are also other immunological mechanisms not easily differentiated.
Lactose intolerance is a non-immunological disease which is due to an enzyme deficiency.
Coeliac disease involves the immune system, but the mechanism is not fully understood. Patterns of the most common allergens vary geographically and culturally. Evidence suggests that the probability of outgrowing a food allergy is dependent upon the food allergen and the patient' compliance with the elimination diet. Allergies to peanut, nuts, fish and other seafood appear to be more persistent. A total elimination of the identified food from the diet is the recommended treatment in severe cases of food allergy.