Open Clinic-Based Peanut Food Challenges are a Viable and Safe Method of Evaluating Clinical Sensitivity and Tolerance

Oral food challenges (OFC) help determine presence of food allergy or tolerance. Indications for peanut (OFC) are not standardized. Decision to challenge is based on history, percutaneous skin testing (PST) and serum specific IgE (sIgE). We compared published OFC criteria for sIgE levels and PST wheal size to those used in a tertiary academic allergy practice. Prior published data recommend sIgE or PST which is < 25% of the 95% PPV of a reaction (sIgE < 3.5 kUA/L or PST wheal size ≤ 8mm). Retrospective chart review was performed for 26 peanut OFC (23m - 74 yrs, 46% male) performed January 2011-July 2011. sIgE and PST wheal size in our study population were compared to published values. 25 patients met criteria for OFC and one exceeded both challenge criteria. 15 had pre-OFC sIgE testing levels below 0.88kAU/L, representing <25% of 3.5kAU/L. 3 of 20 with PST had wheal size ≥ 4mm (range 0-40mm). The patient not meeting criteria, and 4 patients who met criteria failed OFC with development of urticaria and puritus. All subjects who met criteria had a history of no accidental exposures; urticaria on first exposure; and exceeded either sIgE or PST for peanut OFC. Peanut OFC can safely be preformed by following published guidelines. In our experience, patients who met criteria for peanut OFC but failed challenges had urticaria on first exposure, were without a history of accidental exposure, and exceeded one criteria for OFC.