Peanut allergy is considered to be of high risk and persists in 80% of cases. There is a tendency, therefore, to avoid evaluation by oral food challenge (OFC) in the presence of evidence for sensitization.
Patients (n=73, 65.8% male) ranging from 1.6-39.9 years (median, 4.5) with a history suggestive of an allergic reaction to peanut (Group A=38) or a dietary avoidance to peanuts from a variety of reasons including atopic dermatitis (Group B=35) underwent skin prick test (SPT, positive response wheal diameter ≥2) and oral food challenge (OFC) to peanuts and tree nuts. Twenty additional patients were excluded because of a history of a definitive reaction within the past year, a severe anaphylactic reaction or unstable asthma.
Regarding peanuts, 54/73 (73.9%) of patients were SPT+, while only 26/73 (35.6%) were OFC+. 29/38 (76.3%) and 25/35 (71.4%) of Group A and Group B, respectively, were SPT+. Surprisingly, however, only 15/29 (51.7%) of Group A, SPT+ patients were positive on OFC. Furthermore, 11/25 of Group B SPT+ patients were positive on OFC. While 18/21 patients (10 from group A and 11 from group B) with a history of atopic dermatitis were SPT+ to peanut, only 9 (42.9%) were OFC+. Regarding sensitization to tree nuts, 22/34 patients were SPT+ to at least one tree nut, and 6/16 (37.5%) confirmed allergy to one of those nuts on OFC.
Unless clinically contraindicated, patients sensitized to peanuts that either avoided or have a suggestive history of an allergic reaction to peanut should be evaluated by OFC.