An immunological approach to the diagnosis of food sensitivity.

Nineteen patients with delayed onset food sensitivity were compared with fourteen patients with immediate reactions and twenty‐one non‐atopic subjects in terms of clinical symptoms, foods involved and IgE mediated immunological reactions. The immediate reactors were frequently positive to all tests used: skin tests (71%), allergen induced leucocyte histamine release (71%), radioimmunodiffusion (55%) and skin window (55%). Those with the delayed onset variety were seldom positive by skin testing (13%), or skin window (0%), while 39% were positive by leucocyte histamine release and 48% demonstrated specific IgE food antibodies. Control subjects had negative responses to immunological tests for IgE antibody except for leucocyte histamine release (24%). Reasons for the differences between immediate and delayed onset food sensitivity in clinical symptoms, foods involved and immunologic parameters are discussed. A careful history in conjunction with the elimination and challenge technique remains the most useful tool at present for the delayed onset group. In vitro methods for detecting specific IgE responses may also prove to be helpful.