Epidemiology, incidence and clinical aspects of food allergy

Clinical manifestations of food allergy (FA) include a large variety of symptoms, most of which are gastrointestinal. Among the various clinical conditions, cow's milk protein allergy (CMPA) usually appears during early infancy; therefore, it is predominantly a problem of childhood. As with any type of FA, the diagnosis of CMPA rests mostly on clinical observation rather than on laboratory tests. Our studies confirm that both skin tests and RAST are valuable tools in the diagnosis. In particular, our follow-up study of a group of infants with CMPA demonstrates that the majority of RAST-positive subjects do not tolerate cow's milk after many years, whereas all RAST-negative infants tolerate cow's milk in their second year of life. Accordingly, RAST may be useful either in the diagnosis or in the prognosis of CMPA. It is generally agreed that treatment of FA should center on avoidance diets. This may not be easy in children with multiple allergies. Prophylactic drugs may be very useful. Disodium cromoglycate, for instance, seems to be effective in the prevention of IgE-mediated FA. They may also be needed when symptoms persist, mostly because of lack of compliance with the antigen avoidance diet. Early prophylaxis against FA appears to be best achieved by breast-feeding. Exclusive breast-feeding should be encouraged for as long as possible when there is a family history of allergy.