Background: The diagnosis of nut allergy causes anxiety. Few studies exist that estimate risk of reactions and inform management.
Objective: To describe frequency and circumstances of reactions after the institution of a management plan.
Methods: Prospective study of children with peanut/nut allergy with an allergist's management plan. Severity and circumstances of worst reaction before diagnosis (index) and follow-up reactions were evaluated.
Results: A total of 785 children were followed for 3640 patient-years from diagnosis. Index reactions were mild in 66% (516), moderate in 29% (224), and severe in 5% (45). Fourteen percent (114/785) had follow-up reactions (3% annual incidence rate). Ninety percent had the same/reduced severity grade, and 1 of 785 (0.1%) had a severe reaction. Preschool children (n = 263) had a low incidence of reactions, and none were severe. There was a 3-fold reduction in injected epinephrine use from that used in the index reaction, required in 1 severe reaction, never twice; 14% (16/114) required no medication, 78% only oral antihistamines. Forty-eight percent reacted to the index nut type, 19% to a different nut (55% sensitized at diagnosis, 14% not sensitized, 31% not tested). Accidental versus index reactions were 4-fold more likely to be a result of contact exposure rather than ingestion. Contact reactions were always mild. Most (53%) reactions occurred at home, 5% in school, 21% at other sites (21% not recorded). The nut was given by a parent/self in 69 (61%) reactions or teacher in 5 (4%).
Conclusion: With a comprehensive management plan, accidental reactions were uncommon and usually mild, most requiring little treatment; 99.8% self-treated appropriately and 100% effectively.