An observed serving dose may not be necessary following a standard divided-dose FPIES oral food challenge

International consensus guidelines recommend administering the challenge food at a dose of 0.06 to 0.6 g of the food protein per kilogram of body weight (not to exceed 3 g of protein or 10 g of total food) in 3 equal doses over 30 minutes.1 When a very low dose of food protein is administered and if there is no reaction after 2 to 3 hours of observation, some experts advocate administration of an age-appropriate serving, followed by an additional 4 hours of observation.1 We reviewed our experience with FPIES OFCs to evaluate whether an observed serving is necessary 2 to 3 hours after the initial divided-dose OFC. [...]our data suggest that most patients undergoing FPIES OFCs react to the initial divided dose if at least 0.2 g/kg of protein is administered. Characteristic Value No. of patients 46 No. of OFCs 88 Sex, n (%) Female 25 (54) Male 21 (46) Age at diagnosis (mo) Median 10 Range 0.5-32 Age at OFC (mo) Median 18.5 Range 6-118 History of atopy, n (%) 17 (40) Family history of atopy, n (%) 34 (74) ED visit for FPIES reaction, n (%) 23 (50) FPIES reaction to: n (%) 1 Food 18 (39) >1 Food 28 (61) Incriminated food by history, n (%) Milk 18 (39) Soy 8 (17) Rice 16 (35) Oat 18 (39) Wheat 2 (4) Other solid foods 21 (46) Median (n) eliciting dose during OFC (g/kg) Uncooked milk 0.4 (3) Soy 0.3 (1) Rice 0.2 (1) Lightly cooked egg 0.2 (1) Baked egg 0.2 (1) Cooked cheese 0.5 (1) Peanut 0.4 (1) Pork 0.4 (1) IgE sensitization, n (%) FPIES food 3 (7) Other foods 7 (15) OFCs categorized as high risk, n (%) 68 (77) Table I Characteristics of subjects who underwent FPIES OFCs