Food allergies and other adverse reactions to foods.

Adverse reactions to foods do occur. Their true degree of prevalence remains unknown. Many mechanisms are involved, including events at the gut mucosa surface, immunologic pathways, and nonimmunologic and possibly genetic influences, not all of which have yet been well studied. The major manifestations of food allergy have been cutaneous, gastrointestinal, and pulmonary. Others are less convincingly established. Of particular interest is the likelihood that certain rheumatic symptoms may be related to food sensitivity. Establishing a diagnosis of adverse food reaction requires thoughtful clinical evaluation and laboratory testing, confirmatory immunologic studies, and double-blind food challenge. Skin testing is a valuable screening tool and can help direct the physician to those patients for whom double-blind food challenge may be indicated. The simplest therapy is avoidance of foods to which an individual is sensitive. Sodium cromoglycate, antihistamines, prostaglandin synthetase inhibitors, and steroids have been used, but their efficacy has not yet been carefully evaluated.