Dietary exposures and allergy prevention in high-risk infants.

Infants at high risk for developing a food allergy have either an atopic condition (such as eczema) themselves or an immediate family member with such a condition. Breastfeeding should be promoted and supported regardless of issues pertaining to food allergy prevention, but for infants whose mothers cannot or choose not to breastfeed, using a specific formula (i.e., hydrolyzed formula) is not recommended to prevent food allergies. When cow's milk protein formula has been introduced in an infant's diet, make sure that regular ingestion (as little as 10 mL daily) is maintained to prevent loss of tolerance. For high-risk infants, there is compelling evidence that introducing allergenic foods early-at around 6 months, but not before 4 months of age-can prevent common food allergies, and allergies to peanut and egg in particular. Once an allergenic food has been introduced, regular ingestion (e.g., a few times a week) is important to maintain tolerance. Common allergenic foods can be introduced without pausing for days between new foods, and the risk for a severe reaction at first exposure in infancy is extremely low. Pre-emptive in-office screening before introducing allergenic foods is not recommended. No recommendations can be made at this time about the role of maternal dietary modification during pregnancy or lactation, or about supplementing with vitamin D, omega 3, or pre- or probiotics as means to prevent food allergy.

Assessing the Diagnostic Properties of a Graded Oral Provocation Challenge for the Diagnosis of Immediate and Nonimmediate Reactions to Amoxicillin in Children.

IMPORTANCE: The diagnostic properties of a graded provocation challenge (PC) among children presenting with a rash in the course of amoxicillin treatment are currently unknown. OBJECTIVE: To assess the accuracy and the negative predictive value of the PC in a cohort of children referred with suspected allergy to amoxicillin. DESIGN, SETTING, AND PARTICIPANTS: A cohort study was conducted between March 1, 2012, and April 1, 2015, at the allergy clinic of the Montreal Children's Hospital, Montreal, Quebec, Canada. All children referred with suspected allergy to amoxicillin were approached. In addition, 346 eligible children were followed up to assess reactions to subsequent use of amoxicillin at the time of illness in cases with negative PC results. Data were collected on clinical characteristics, suspected antibiotic exposure, personal and first-degree relatives' comorbidities, and history of atopy and management of the reaction. Univariate and multivariate logistic regressions were compared to determine factors associated with immediate and nonimmediate reactions to the PC. INTERVENTIONS: All children had a graded PC. MAIN OUTCOMES AND MEASURES: Reactions to the graded PC, the negative predictive value of the PC for nonimmediate reactions, and factors associated with immediate and nonimmediate reactions to the PC. RESULTS: A total of 818 children were assessed (median age, 1.7 years [interquartile range, 1.0-3.9 years]; 441 [53.9%] male). Among all participants, 770 (94.1%) tolerated the PC, 17 (2.1%) developed mild immediate reactions, and 31 (3.8%) developed nonimmediate reactions. The graded PC had a specificity of 100.0% (95% CI, 90.9%-100.0%), a negative predictive value of 89.1% (95% CI, 77.1%-95.5%), and a positive predictive value of 100.0% (95% CI, 86.3%-100.0%). Among all 346 participants eligible for annual follow-up, 250 (72.3%; 95% CI, 67.2%-76.8%) responded, 55 of whom received subsequent full treatment with amoxicillin; 49 of these 55 participants (89.1%) reported tolerance to subsequent full treatment with amoxicillin, while 6 (10.9%) developed nonimmediate cutaneous reactions. History of a reaction occurring within 5 minutes of exposure was associated with immediate reactions to the PC (adjusted odds ratio = 9.6; 95% CI, 1.5-64.0), while a rash that lasted longer than 7 days (adjusted odds ratio = 4.8; 95% CI, 1.4-16.4) and parental history of drug allergy (adjusted odds ratio = 3.0; 95% CI, 1.3-6.8) were associated with nonimmediate reactions to the PC. CONCLUSIONS AND RELEVANCE: Graded PCs provide an accurate and safe confirmatory test for skin-related reactions to amoxicillin. Further studies are required to assess factors associated with the PC outcome groups.

Dietary exposures and allergy prevention in high-risk infants: a joint position statement of the Canadian Society of Allergy and Clinical Immunology and the Canadian Paediatric Society.

Allergic conditions in children are a prevalent health concern in Canada. The burden of disease and the societal costs of proper diagnosis and management are considerable, making the primary prevention of allergic conditions a desirable health care objective. This position statement reviews current evidence on dietary exposures and allergy prevention in infants at high risk of developing allergic conditions. It revisits previous dietary recommendations for pregnancy, breastfeeding and formula-feeding, and provides an approach for introducing solid foods to high-risk infants. While there is no evidence that delaying the introduction of any specific food beyond six months of age helps to prevent allergy, the protective effect of early introduction of potentially allergenic foods (at four to six months) remains under investigation. Recent research appears to suggest that regularly ingesting a new, potentially allergenic food may be as important as when that food is first introduced. This article has already been published (Paediatr Child Health. 2013 Dec;18(10):545-54), and is being re-published with permission from the original publisher, the Canadian Paediatric Society.

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.

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

The diagnosis of peanut allergy (PA) can be complex especially in children never exposed to peanut or with an uncertain history. The aim of the study is to determine which diagnostic algorithms are used by Canadian allergists in such children. Children 1-17 yrs old never exposed to peanut or with an uncertain history having an allergist-confirmed diagnosis of PA were recruited from the Montreal Children's Hospital (MCH) and allergy advocacy organizations. Data on their clinical history and confirmatory testing were compared to six diagnostic algorithms: I. Skin prick test (SPT) >or=8 mm or specific IgE >or=5 kU/l or positive food challenge (+FC); II. SPT >or=8 or IgE >or=15 or +FC; III. SPT >or=13 or IgE >or=5 or +FC; IV. SPT >or=13 or IgE >or=15 or +FC; V. SPT >or=3 and IgE >or=5 or IgE >or=5 or +FC; VI. SPT >or=3 and IgE >or=15 or IgE >or=15 or +FC. Multivariate logistic regression analysis was used to identify factors associated with the use of each algorithm. Of 497 children recruited, 70% provided full data. The least stringent algorithm, algorithm I, was applied in 81.6% (95% CI, 77-85.6%) of children and the most stringent, algorithm VI, in 42.6% (95% CI, 37.2-48.1%).The factor most associated with the use of all algorithms was diagnosis made at the MCH in those never exposed to peanut. Other factors associated with the use of specific diagnostic algorithms were higher paternal education, longer disease duration, and the presence of hives, asthma, eczema, or other food allergies. Over 18% (95% CI, 14.4-23.0%) of children were diagnosed with PA without fulfilling even the least stringent diagnostic criteria.

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.

The predilection of chickenpox exanthema to influenza vaccine injection site.

Annual influenza immunization of children is highly recommended and is usually well tolerated. We report the first case of chickenpox exanthema localized to the influenza vaccination site in a boy with known egg allergy.

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 individual's 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 nurse's 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.

Chronic active gastritis in X-linked lymphoproliferative disease.

Gastric lesions in primary constitutive immune deficiencies include multifocal atrophic gastritis, erosive pangastritis, and a pattern of gastric lesions reminiscent of graft-versus-host disease. We describe the genetic anomalies in 2 monozygotic twins with an X-linked lymphoproliferative disease (XLP; MIM 308240), a rare familial setting of high susceptibility to Epstein-Barr virus (EBV). Since early childhood, both twin brothers exhibited a severe chronic active atrophic pangastritis. A germline screening of the SH2D1A (MIM 300490) and BIRC4 (MIM 300079) genes was performed, and also a high-resolution whole-genome SNP profiling (Infinium Sentrix Human-1 Genotyping BeadChip, Illumina). A 3 Megabase deletion in the Xq25 region, encompassing the SH2D1A gene, was defined by SNP array genotyping. Histologic analysis of yearly or twice yearly gastric biopsies in both children showed a Helicobacter pylori-negative, Epstein-Barr virus-negative chronic active atrophic pangastritis, with superficial ulcer formation, foveolar hyperplasia, glandular dilatation and ultimately pseudopyloric and intestinal metaplasia. No such chronic active inflammatory gastric lesions have been reported to date in XLP. The similarities between XLP and common variable immunodeficiency (MIM 240500) underscore the need for early recognition and close monitoring of these gastric lesions, with special regard to their neoplastic potential. No infectious cause was determined. We favor a dysimmune mechanism in the development of this chronic atrophic gastritis, presenting a striking similarity to the recently described atrophic autoimmune pangastritis.

Immune function in autistic children.

BACKGROUND: There have been reports that some children with autistic spectrum disorders have abnormal immune function. However, data in this area remain scarce and conflicting. OBJECTIVE: To evaluate the immune function of a series of autistic children in the context of this proposed association. METHODS: We prospectively collected data on 24 autistic children who, between January 1, 1996, and September 30, 1998, were referred unsolicited to an immunology clinic. We examined the clinical history and evaluated immunoglobulin levels; specific antibody titers to diphtheria, tetanus, and Haemophilus influenzae; T- + B-cell numbers; T-cell proliferation; and complement studies. RESULTS: Seven of the 24 children had a history of recurrent infections. Only 2 patients had immunoglobulin levels that were outside the age-adjusted reference ranges, 1 of whom was subsequently diagnosed as having common variable immune deficiency. All the patients had normal in vitro T-cell function and complement study results, and only 2 of 24 patients had subtle derangements in T-cell numbers. Elevated levels of IgE were found in 5 patients, which correlated with a clinical history of atopy. Low diphtheria or tetanus antibody levels were found in 12 patients, but in 11 of these, vaccination status was not up-to-date. CONCLUSIONS: Most of the autistic children studied had normal immune function, suggesting that routine immunologic investigation is unlikely to be of benefit in most autistic children and should be considered only when there is a history suggestive of recurrent infections.