Oral food challenges in a practice setting apart from hospitals and academic centers.

To the Editor: On reading the letter from Lieberman et al, it seemed interesting to compare the results of challenges performed in a privatepractice setting not connected to an academic medical center or within a hospital facility. We perform about 12 to 15 open food challenges per month in an office setting. For comparison, we reviewed the last 100 challenges performed. The foods challenged were peanut, almond, walnut, pecan, hazelnut, cashew, pistachio, pine nut, egg, baked egg, milk, baked milk, shrimp, scallops, lobster, soy, sesame, and wheat. Challenges were performed in patients 3 to 18 years of age. Sixty percent were male. Criteria for selection included no reaction to the selected foods in the previous year and no history of anaphylaxis. Sensitization was a positive skin test response (wheal diameter, >_3 mm than that elicited by the negative control) and/or a detectable serum specific IgE level to the selected food, as determined by using the Phadia ImmunoCAP (Phadia AB, Uppsala, Sweden) performed by local laboratories (>0.35 kU/ L). The decision to challenge was based on clinical histories, skin test results, food-specific IgE determinations, and physician and family preferences after discussing the possibility of a positive (failed) challenge result. Challenges to food were generally not performed if the skin test wheal diameter was greater than 10 mm (in this group of 100 challenges, the range was 0-10 mm, except for 2 patients [15 mm in a baked egg challenge and 12 mm in a baked milk challenge]) and/or the serum antibody level was greater than 2 kU/L for peanut and tree nuts. In 100 children therewere 17 positive challenge results (19% in Lieberman’s subjects), with 15 (88%) challenges in sensitized patients and 2 challenges in nonsensitized patients. Of the 83 negative challenge results, 52 (63%) were in subjects sensitized to the food, and 31 were in subjects not sensitized to the food. Two reactions required injections of epinephrine for (1) marked upper respiratory tract symptoms and urticaria with extreme discomfort during a baked milk challenge or (2) vomiting, urticaria, cough, wheeze, and pharyngeal pruritus. Both of these subjects recovered quickly after a single epinephrine injection without further treatment. This is similar to the 1.7% of the subjects in the study by Lieberman et al requiring epinephrine and with epinephrine use in food challenges previously reported by Jarvinen et al, including observations from another group of our challenge patients. These observations compare favorably with those reported by Lieberman et al, supporting the conclusion that challenges in offices away from academic centers are safe, successful, and useful. S. Allan Bock, MD Lois Cherrington, RN