Early ReportLong-term prospective observational study of patients with peanut and nut allergy after participation in a management plan
Introduction
Peanut and nut allergy is now common and an important cause of severe or fatal anaphylaxis. There was a substantial rise in prevalence in the 1990s. Confirmed peanut allergy was found in one in 2004-year-olds in the Isle of Wight, UK,1 and a telephone survey relying on self-diagnosis showed a prevalence of 1·1% for peanut or nut allergy in the USA.2 Reports of deaths in the press cause anxiety among the public, particularly among parents of children with nut allergy. Peanut is the commonest food causing fatal or near fatal anaphylaxis.3, 4
Management must take these risks into account, but difficulties arise because little is known of the clinical features or natural history. The first study to define clinical features in a large series found that the worst reaction in a third was cutaneous only.5 In two-thirds, the potentially dangerous feature was respiratory-tract involvement (laryngeal oedema and/or asthma), which varied in severity. Severe dyspnoea, cyanosis, or respiratory arrest occurred in life-threatening reactions.
Management of nut allergy by non-specialists is poor. Patients are often unable to obtain advice (which applies to most of the fatal reactions), or epinephrine for self-injection is given to patients with trivial allergy. There are no data on management strategies to prevent or reduce further reactions in those known to be allergic. Particular problems in management are: which patients are at risk of severe reactions, and which patients should carry epinephrine autoinjectors.
On the basis of our knowledge of clinical features of nut allergy,5 we devised a management plan in 1993, consisting of advice on avoidance of nuts and the provision of medication to allow early self-initiation of treatment of reactions or initiation by parents and school staff. Reinforcement and retraining was given at annual follow-up. We prospectively followed individuals with peanut and tree-nut allergies after they had been identified in a specialist clinic to establish the frequency of subsequent reactions, their severity and treatment, and risk factors for repeated or severe reactions.
Section snippets
Patients
Patients were unselected consecutive referrals to a regional specialist allergy clinic, and the diagnosis was made from the history and confirmed by skin prick tests to peanut or individual tree-nut extracts.
A detailed history was taken of all reactions, and the index reaction (the most severe reaction occurring before referral) was graded for severity. The amount of nut eaten (exposure) was also recorded.
Grading
Grade 1 (mild)—localised cutaneous erythema/urticaria/angioedema/oral pruritis; grade 2
Participants
567 patients were followed prospectively: median age at onset of nut allergy 3 years (range 4 months to 55 years), median age at presentation 7·5 years (range 7 months–65 years) and the sex ratio was 1:1. 181 (32%) were under 5 years old, 193 (34%) were 5–11 years, 57 (10%) were 12–17 years, and 136 (24%) were older than 17 years. 351 (62%) patients were allergic to one nut only and 171 (30%) to more than one nut. 351 (62%) were allergic to peanuts, 85 (15%) to brazil nuts, 35 (6%) to hazelnut,
Discussion
Evidence-based data on the management of nut allergy are lacking, so that advice varies from “just avoid nuts” or “nothing needs to be done” to the prescription of epinephrine autoinjectors to anyone, including those with the mildest reactivity, without instruction. At one end of the spectrum, patients die having received no advice whereas, at the other, the concern about life-threatening reactions leads to indiscriminate prescribing of epinephrine syringes. The proliferation of these in
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2021, Journal of Allergy and Clinical ImmunologyCitation Excerpt :The Preferred Reporting Items for Systematic Reviews and Meta-Analyses diagram for this systematic review is shown in Fig 1. A total of 86 studies were eligible for inclusion (76 from the original search and a further 10 from when the search was updated in 2021),2,3,10-16,21-97 representing 88 data sets (2 studies reported both retrospective and prospective data sets in the same publication)14,16 and a total of 36,557 anaphylaxis events (see Tables E13 and E14). A total of 35 studies reported food-induced reactions only, whereas 1 study reported venom-induced reactions only (see Tables E4 and E5).