Diagnosis and treatment of food allergies.

Clinical classajication of food allergy Food allergy has become a contentious subject. True food allergy is dependent on evidence of intolerance to a specific food-in other words recurrence of symptoms on two or more occasions when that food is taken (preferably blind and in the presence of the doctor). There should also be direct or indirect evidence of an immunological component to that reaction. Patients may have ‘simple’ intolerance to foods rather than true allergy for various reasons. For example, the patient who develops tachycardia while drinking ten strong cups of coffee daily has a pharmacological cause of food intolerance. The patient with food-induced migraine may in some instances have low phenol sulphotransferase levels. Thus an enzyme defect may be misinterpreted as an allergy. If we are to study well-defined groups we should not talk of food allergy in these cases any more than we should for a patient with gallstones who cannot eat eggs. Furthermore, food allergy is frequently applied to people who for one reason or another have a behavioural aversion to foods without any objective evidence that that food upsets them at all. The correct diagnosis in such cases may range from anorexia nervosa or food fads to hyperventilation syndrome. The following represents a clinical classification of food allergy based on the experience of the Guy’s Hospital Allergy Clinic. Alimentary tract reactions. These can be divided into: ( I ) Oropharyngeal reactions. ( 2 ) Lower gastrointestinal reactions, e.g. nausea, vomiting and diarrhoea.