AN EVALUATION OF THE SENSITIVITY OF SUBJECTS WITH PEANUT ALLERGY TO VERY-LOW DOSES OF PEANUT PROTEIN - A RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED FOOD CHALLENGE STUDY

Background: The minimum dose of food protein to which subjects with fo od allergy have reacted in double-blind, placebo-controlled food chall enges is between 50 and 100 mg. However, subjects with peanut allergy often report severe reactions after minimal contact with peanuts, even through intact skin. Objective: We sought to determine whether adults previously proven by challenge to be allergic to peanut react to very low doses of peanut protein. Methods: We used a randomized, double-bl ind, placebo-controlled food challenge of 14 subjects allergic to pean uts with doses of peanut ranging from 10 mu g to 50 mg, administered i n the form of a commercially available peanut flour. Results: One subj ect had a systemic reaction to 5 mg of peanut protein, and two subject s had mild objective reactions to 2 mg and 50 mg of peanut protein, re spectively. Five subjects had mild subjective reactions (1 to 5 mg and 4 to 50 mg). All subjects with convincing objective reactions had sho rt-lived subjective reactions to preceding doses, as low as 100 mu g i n two cases. Five subjects did not react to any dose up to 50 mg. Conc lusion: Even in a group of well-characterized, highly sensitive subjec ts with peanut allergy, the threshold dose of peanut protein varies, A s little as 100 mu g of peanut protein provokes symptoms in some subje cts with peanut allergy.