Rhoda Kagan

Is the prevalence of peanut allergy increasing? A 5-year follow-up study in children in Montreal

BACKGROUND Studies suggest that peanut allergy prevalence might be increasing, but these results have not yet been substantiated. OBJECTIVE We conducted a follow-up study to determine whether peanut allergy prevalence in Montreal is increasing. METHODS Questionnaires regarding peanut ingestion were administered to parents of children in randomly selected kindergarten through grade 3 classrooms between December 2000 and September 2002 and between October 2005 and December 2007. Respondents were stratified as (1) peanut tolerant, (2) never/rarely ingest peanut, (3) convincing history of peanut allergy, or (4) uncertain history of peanut allergy. Children in group 3 with positive skin prick test responses were considered to have peanut allergy. Children in groups 2 and 4 with positive skin prick test responses had peanut-specific IgE levels measured, and if the value was less than 15 kU/L, an oral peanut challenge was performed. Multiple imputation was used to generate prevalence estimates that incorporated respondents providing incomplete data and nonrespondents. RESULTS Of 8,039 children surveyed in 2005-2007, 64.2% of parents responded. Among those providing complete data, the prevalence was 1.63% (95% CI, 1.30% to 2.02%) in 2005-2007 versus 1.50% (95% CI, 1.16% to 1.92%) in 2000-2002. After adjustment for missing data, the prevalence was 1.62% (95% credible interval, 1.31% to 1.98%) versus 1.34% (95% credible interval, 1.08% to 1.64%), respectively. The differences between the prevalences in 2005-2007 and 2000-2002 were 0.13% (95% credible interval, -0.38% to 0.63%) among those providing complete data and 0.28% (95% credible interval, -0.15% to 0.70%) after adjustment for missing data. CONCLUSIONS This is the first North American study to document temporal trends in peanut allergy prevalence by corroborating history with confirmatory tests. The results suggest a stable prevalence, but wide CIs preclude definitive conclusions.

Role of food labels in accidental exposures in food-allergic individuals in Canada

BACKGROUND Little is known about the impact of food labeling on the allergic consumer. OBJECTIVE To determine the proportion of food-allergic individuals attributing an accidental exposure to inappropriate labeling, failure to read a food label, or ignoring a precautionary statement and to identify factors associated with accidental exposures. METHODS Food-allergic individuals or their caregivers were recruited from a Canadian registry of individuals with a physician-confirmed diagnosis of peanut allergy and from allergy awareness organizations. Participants completed questionnaires regarding accidental exposures due to specific food labeling issues. The association between accidental exposures and characteristics of food-allergic individuals or their caregivers was estimated using multivariate logistic regression models. RESULTS Of 1,862 potential participants, 1,454 (78.1%) responded. Of the 47.8% (95% confidence interval [CI], 45.1%-50.5%) of respondents who experienced an accidental exposure, 47.0% (95% CI, 43.1%-50.9%) attributed the event to inappropriate labeling, 28.6% (95% CI, 25.1%-32.2%) to failure to read a food label, and 8.3% (95% CI, 6.3%-10.7%) to ignoring a precautionary statement. Food-allergic individuals who were allergic to peanut, tree nut, fish, or shellfish were less likely to experience an accidental exposure due to the allergen not being identified in plain language. CONCLUSIONS A considerable proportion of accidental exposures are attributed to inappropriate labeling, failure to read labels, and ignoring precautionary statements. Clear and consistent labeling of food allergens combined with increased consumer education is necessary to improve consumer confidence and compliance and to reduce accidental exposures.

Safe vaccination of patients with egg allergy with an adjuvanted pandemic H1N1 vaccine

BACKGROUND Because influenza vaccine contains some residual egg protein, there is a theoretic risk of anaphylaxis when vaccinating patients with egg allergy. The objective of this study was to estimate the risk of anaphylaxis in children with egg allergy administered an adjuvanted monovalent 2009 pandemic influenza A/H1N1 influenza vaccine (Arepanrix; GlaxoSmithKline, Mississauga, Ontario, Canada). METHODS Patients with confirmed egg allergy with a history of respiratory or cardiovascular reactions after egg ingestion were vaccinated in 2 divided doses (10% and 90%) administered at a 30-minute interval, whereas children with other types of egg-induced allergic reactions were vaccinated with a single dose. All patients remained under observation for 60 minutes after vaccination. A 24-hour follow-up telephone call was made to detect any delayed reaction. The main outcome was the occurrence of an anaphylactic reaction according to criteria specified by the Brighton Collaboration. RESULTS Among the 830 patients with confirmed egg allergy, only 9% required the vaccine to be administered in divided doses. No patient had an anaphylactic reaction. Nine patients had minor allergic symptoms treated with an antihistamine (1 in the 60 minutes after vaccination and 8 in the following 23 hours), and 3 others received salbutamol (1 in the first 60 minutes after vaccination). Further vaccination of more than 3600 other children with reported egg allergy caused no anaphylaxis based on the criteria of the Brighton Collaboration, although 2 patients received epinephrine for symptoms compatible with allergy. CONCLUSION Although anaphylaxis after influenza immunization is a theoretic risk, vaccination of patients with egg allergy with an adjuvanted monovalent pH1N1 influenza vaccine resulted in no cases of anaphylaxis and on that basis appears safe.

Availability of the epinephrine autoinjector at school in children with peanut allergy

BACKGROUND Peanut allergy accounts for most severe food-related allergic reactions, and accidental exposures are frequent. Delayed administration of epinephrine and the allergic individuals failure to personally carry epinephrine contribute to fatal outcomes. OBJECTIVES To describe epinephrine autoinjector availability at school and to determine factors that might affect autoinjector availability in children allergic to peanut. METHODS Two hundred seventy-one children with peanut allergy living in Quebec were queried about their autoinjector. Logistic regression models were used to select factors associated with device availability. RESULTS Four of 271 children diagnosed as having peanut allergy were not prescribed autoinjectors. Forty-eight percent of the children did not carry the autoinjector with them at school. In 78.0% of those, the autoinjector was located in the nurses or another school office, which was staffed by a full-time nurse only in 18.5%. Of all the respondents, those administered epinephrine for a previous reaction (odds ratio [OR], 2.7; 95% confidence interval [CI], 1.3-5.7), older children (OR, 1.1; 95% CI, 1.0-1.2), and those living only with their mother (OR, 3.4; 95% CI, 1.0-11.0) were more likely to carry the autoinjector with them at school. Of children 7 years or older, those who experienced a severe reaction were more likely to carry their autoinjector (OR, 3.3; 95% CI, 1.4-8.1). CONCLUSIONS Almost 50% of children allergic to peanut might experience a delay in anaphylaxis treatment due to limited access to their device. More education is required regarding the importance of a readily available autoinjector.

Peanut-free guidelines reduce school lunch peanut contents

Background: Some schools implement peanut-free guidelines (PFG) requesting omission of peanut from lunches. Our study assessed parental awareness of, and adherence to, PFG by comparing the percentage of lunches containing peanut between primary school classes with and without PFG in Montreal, Québec. Methods: Parents, school principals and teachers were queried concerning the school’s PFG and children’s lunches were inspected by a dietician for peanut-containing foods. Results: When lunch peanut contents were compared in randomly selected classrooms, peanut was found in 5/861 lunches in classes with PFG (0.6%, 95% CI 0.2% to 1.4%) and in 84/845 lunches in classes without PFG (9.9%, 95% CI 8.0% to 12.2%), a 9.4% (95% CI 7.3% to 11.4%) difference. Conclusions: Our findings demonstrate that PFG are effective in reducing peanut in classrooms providing a basis for future research that should address whether or not the reduction in peanut achieved by restrictive lunch policies decreases the morbidity associated with peanut allergy in the school setting.

Establishing the diagnosis of peanut allergy in children never exposed to peanut or with an uncertain history: a cross-Canada study

Ben‐Shoshan M, Kagan R, Primeau M‐N, Alizadehfar R, Turnbull E, Harada L, Dufresne C, Allen M, Joseph L, St. Pierre Y, Clarke A. Establishing the diagnosis of peanut allergy in children never exposed to peanut or with an uncertain history: a cross‐Canada study.
Pediatr Allergy Immunol 2010: 21: 920–926.
© 2010 John Wiley & Sons A/S