Relevance of casual contact with peanut butter in children with peanut allergy

Background: Casual skin contact or inhalation of peanut butter fumes is reported and feared to cause allergic reactions in highly sensitive children with peanut allergy but has not been systematically studied. Objective: We sought to determine the clinical relevance of exposure to peanut butter by means of inhalation and skin contact in children with peanut allergy. Methods: Children with significant peanut allergy (recent peanut-specific IgE antibody concentration >50 kIU/L or evidence of peanut-specific IgE antibody and one of the following: clinical anaphylaxis, a reported inhalation-contact reaction, or positive double-blind, placebo-controlled oral challenge result to peanut) underwent double-blind, placebo-controlled, randomized exposures to peanut butter by means of contact with intact skin (0.2 mL pressed fiat for 1 minute) and inhalation (surface area of 6.3 square inches 12 inches from the face for 10 minutes). Placebo challenges were performed by using soy butter mixed with histamine (contact), and scent was masked with soy butter, tuna, and mint (inhalation). Results: Thirty children underwent the challenges (median age, 7.7 years; median peanut IgE level, >100 kIU/L; 13 with prior history of contact and 11 with inhalation reactions). None experienced a systemic or respiratory reaction. Erythema (3 subjects), pruritus without erythema (5 subjects), and wheal-and-flare reactions (2 subjects) developed only at the site of skin contact with peanut butter. From this number of participants, it can be stated with 96% confidence that at least 90% of highly sensitive children with peanut allergy would not experience a systemic-respiratory reaction from casual exposure to peanut butter. Conclusions: Casual exposure to peanut butter is unlikely to elicit significant allergic reactions. The results cannot be generalized to larger exposures or to contact with peanut in other torms (flour and roasted peanuts).