Reduced risk of peanut sensitization following exposure through breast-feeding and early peanut introduction.

BACKGROUND: Recent trials have shown that avoiding peanuts during infancy increases the risk of peanut allergy; however, these studies did not address maternal peanut consumption. OBJECTIVE: We sought to investigate the relationship between maternal peanut consumption while breast-feeding, timing of direct peanut introduction, and peanut sensitization at age 7 years. METHODS: Secondary analysis of a nested cohort within the 1995 Canadian Asthma Primary Prevention Study intervention study was performed. Breast-feeding and maternal and infant peanut consumption were captured by repeated questionnaires during infancy. Skin prick testing for peanut sensitization was performed at age 7 years. RESULTS: Overall, 58.2% of mothers consumed peanuts while breast-feeding and 22.5% directly introduced peanuts to their infant by 12 months. At 7 years, 9.4% of children were sensitized to peanuts. The lowest incidence (1.7%) was observed among children whose mothers consumed peanuts while breast-feeding and directly introduced peanuts before 12 months. Incidence was significantly higher (P < .05) if mothers consumed peanuts while breast-feeding but delayed introducing peanuts to their infant beyond 12 months (15.1%), or if mothers avoided peanuts themselves but directly introduced peanuts by 12 months (17.6%). Interaction analyses controlling for study group and maternal atopy confirmed that maternal peanut consumption while breast-feeding and infant peanut consumption by 12 months were protective in combination, whereas either exposure in isolation was associated with an increased risk of sensitization (P interaction = .003). CONCLUSIONS: In this secondary analysis, maternal peanut consumption while breast-feeding paired with direct introduction of peanuts in the first year of life was associated with the lowest risk of peanut sensitization, compared with all other combinations of maternal and infant peanut consumption.

Wheeze trajectories are modifiable through early-life intervention and predict asthma in adolescence.

BACKGROUND: The objectives of this study were to identify developmental trajectories of wheezing using data-driven methodology, and to examine whether trajectory membership differentially impacts the effectiveness of primary preventive efforts that target modifiable asthma risk factors. METHODS: Secondary analysis of the Canadian Asthma Primary Prevention Study (CAPPS), a multifaceted prenatal intervention among children at high risk of asthma, followed from birth to 15 years. Wheezing trajectories were identified by latent class growth analysis. Predictors, intervention effects, and asthma diagnoses were examined between and within trajectory groups. RESULTS: Among 525 children, 3 wheeze trajectory groups were identified: Low-Progressive (365, 69%), Early-Transient (52, 10%), and Early-Persistent (108, 21%). The study intervention was associated with lower odds of Early-Transient and Early-Persistent wheezing (P < .01). Other predictors of wheeze trajectories included, maternal asthma, maternal education, city of residence, breastfeeding, household pets, infant sex and atopy at 12 months. The odds of an asthma diagnosis were three-fold to six-fold higher in the Early-Persistent vs Low-Progressive group at all follow-up assessments (P = .03), whereas Early-Transient wheezing (limited to the first year) was not associated with asthma. In the Early-Persistent group, the odds of wheezing were lower among intervention than control children (adjusted odds ratio: 0.67; 95% CI: 0.48; 0.93) at 7 years. CONCLUSIONS: Using data-driven methodology, children can be classified into clinically meaningful wheeze trajectory groups that appear to be programmed by modifiable and non-modifiable factors, and are useful for predicting asthma risk. Early-life interventions can alter some wheeze trajectories (ie, Early-Persistent) in infancy and reduce wheezing prevalence in mid-childhood.

Diagnosis and management of asthma in preschoolers: A Canadian Thoracic Society and Canadian Paediatric Society position paper.

Asthma often starts before six years of age. However, there remains uncertainty as to when and how a preschool-age child with symptoms suggestive of asthma can be diagnosed with this condition. This delays treatment and contributes to both short- and long-term morbidity. Members of the Canadian Thoracic Society Asthma Clinical Assembly partnered with the Canadian Paediatric Society to develop a joint working group with the mandate to develop a position paper on the diagnosis and management of asthma in preschoolers. In the absence of lung function tests, the diagnosis of asthma should be considered in children one to five years of age with frequent (≥8 days/month) asthma-like symptoms or recurrent (≥2) exacerbations (episodes with asthma-like signs). The diagnosis requires the objective document of signs or convincing parent-reported symptoms of airflow obstruction (improvement in these signs or symptoms with asthma therapy), and no clinical suspicion of an alternative diagnosis. The characteristic feature of airflow obstruction is wheezing, commonly accompanied by difficulty breathing and cough. Reversibility with asthma medications is defined as direct observation of improvement with short-acting ß2-agonists (SABA) (with or without oral corticosteroids) by a trained health care practitioner during an acute exacerbation (preferred method). However, in children with no wheezing (or other signs of airflow obstruction) on presentation, reversibility may be determined by convincing parental report of a symptomatic response to a three-month therapeutic trial of a medium dose of inhaled corticosteroids with as-needed SABA (alternative method), or as-needed SABA alone (weaker alternative method). The authors provide key messages regarding in whom to consider the diagnosis, terms to be abandoned, when to refer to an asthma specialist and the initial management strategy. Finally, dissemination plans and priority areas for research are identified.

L'asthme fait souvent son apparition avant l'âge de six ans. Cependant, il subsiste des incertitudes relativement à quand et comment un enfant d'âge préscolaire ayant des symptômes de type asthmatique peut être diagnostiqué avec cette condition. Ceci retarde le traitement et contribue à la morbidité à court et à long terme. L'Assemblée clinique sur l'asthme de la Société canadienne de thoracologie s'est associée à la Société canadienne de pédiatrie pour créer un groupe de travail conjoint afin de préparer un document de principes sur le diagnostic et la prise en charge de l'asthme chez les enfants d'âge préscolaire. En l'absence de mesures de la fonction pulmonaire, le diagnostic d'asthme devrait être envisagé chez les enfants de un à cinq ans ayant des symptômes de type asthmatique fréquents (≥8 jours/mois) ou des exacerbations récurrentes (≥2) (épisodes accompagnés de signes compatibles). Le diagnostic nécessite une documentation objective des signes cliniques ou un compte rendu parental convaincant de symptômes d'obstruction des voies respiratoires et de réversibilité de l' obstruction (amélioration suite à un traitement pour l'asthme), ainsi que l'absence de suspicion clinique de tout autre diagnostic. La respiration sifflante, souvent accompagnée de difficultés respiratoires et de toux, est le signe cardinal de l'obstruction des voies respiratoires. La réversibilité à la suite de la prise de médicaments pour l'asthme se définie par l'observation directe par un professionnel de la santé compétent, d'une amélioration après l'administration de ß2-agonistes à courte durée d'action (BACA) (accompagnés ou non de corticostéroïdes par voie orale) pendant une exacerbation aigue (méthode diagnostique privilégiée). Cependant, chez les enfants qui n'ont pas à l'examen une respiration sifflante (ni d'autres signes d'obstruction des voies respiratoires), la réversibilité peut être déterminée par un compte rendu parental convaincant d'une réponse symptomatique à un essai thérapeutique de trois mois de corticostéroïdes inhalés, à dose moyenne, avec un BACA au besoin (méthode diagnostique alternative), ou avec seulement un BACA au besoin (méthode diagnostique alternative moins certaine) est recommandé. Les auteurs présentent des messages clés quant aux enfants chez lesquels on doit envisager le diagnostic, quant aux termes désuets à abandonner, quant aux situations pour lesquelles on doit orienter l'enfant vers un spécialiste de l'asthme et quant à la stratégie de prise en charge initiale. Enfin, ils décrivent la stratégie de diffusion de ces messages et identifient les domaines de recherche prioritaires.

Elevated tryptase level in a child with idiopathic anaphylaxis: a case of hereditary alpha-tryptasemia.

Hereditary alpha-tryptasemia (HαT) is an autosomal dominant disorder estimated to affect 5% of the population. High baseline tryptase level is a consistent finding, but there is a great variability of clinic manifestations, including no symptoms at all. We describe a case of HαT in a 5 years 8 months old girl manifesting with idiopathic anaphylaxis and elevated baseline tryptase level. As more cases of HαT are described, a better understanding of the clinical phenotype will be acquired.

Atopic dermatitis in a high-risk cohort: natural history, associated allergic outcomes, and risk factors.

BACKGROUND: Atopic dermatitis (AD) is commonly associated with asthma and other atopic disorders in childhood. OBJECTIVE: To evaluate the natural history of AD and its association with other allergic outcomes in a high-risk cohort through the age of 7 years. METHODS: A total of 373 high-risk infants, who had undergone a randomized controlled trial with intervention measures for primary prevention of asthma applied during the first year of life, were assessed for asthma, AD, and allergic sensitization at 1, 2, and 7 years. RESULTS: The multifaceted intervention program did not reduce AD despite reducing the prevalence of asthma significantly. Sixty-two children (16.6%) had AD during the first 2 years (early-onset AD); of these, 26 continue to have AD at the age of 7 years (persistent), whereas 36 no longer had the disease (nonpersistent) at the age of 7 years. Twenty-three children (6.2%) developed AD only after the age of 2 years (late-onset AD). Early-onset AD, persistent or nonpersistent, was associated with increased risk of allergic sensitization to food allergens within the first 2 years of life and asthma diagnosis at year 7. However, only persistent AD was associated with an increased risk of other atopic diseases and allergic sensitization to food and aeroallergens at year 7. Late-onset AD was not associated with atopic diseases or allergic sensitization at year 7 with the exception of Alternaria alternans. CONCLUSION: In this cohort of infants at high risk of asthma, early-onset persistent AD, which was highly associated with atopic sensitization, increased the risk of atopic diseases in later childhood and thus appears to be part of the atopic march.

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.

Eosinophilic esophagitis.

Eosinophilic esophagitis (EoE) is an atopic condition of the esophagus that has become increasingly recognized over the last decade. Diagnosis of the disorder is dependent on the patient's clinical manifestations and histologic findings on esophageal mucosal biopsies. Patients with eosinophilic esophagitis should be referred to both an allergist and gastroenterologist for optimal management, which may include dietary modifications, pharmacologic agents such as corticosteroids, leukotriene modifiers and biologics as well as mechanical dilatation of the esophagus. The epidemiology, pathophysiology, diagnosis, treatment, and prognosis of EoE are discussed in this review.

Atopic dermatitis.

Atopic dermatitis (AD) is a common, chronic skin disorder that can significantly impact the quality of life of affected individuals as well as their families. Although the pathogenesis of the disorder is not completely understood, it appears to result from the complex interplay between defects in skin barrier function, environmental and infectious agents, and immune abnormalities. There are no specific diagnostic tests for AD; therefore, the diagnosis is based on specific clinical criteria that take into account the patient's history and clinical manifestations. Successful management of the disorder requires a multifaceted approach that involves education, optimal skin care practices, anti-inflammatory treatment with topical corticosteroids and/or topical calcineurin inhibitors (TCIs), the use of first-generation antihistamines to help manage sleep disturbances, and the treatment of skin infections. Systemic corticosteroids may also be used, but are generally reserved for the acute treatment of severe flare-ups. Topical corticosteroids are the first-line pharmacologic treatments for AD, and evidence suggests that these agents may also be beneficial for the prophylaxis of disease flare-ups. Although the prognosis for patients with AD is generally favourable, those patients with severe, widespread disease and concomitant atopic conditions, such as asthma and allergic rhinitis, are likely to experience poorer outcomes.

Food allergy.

Food allergy is defined as an adverse immunologic response to a dietary protein. Food-related reactions are associated with a broad array of signs and symptoms that may involve many bodily systems including the skin, gastrointestinal and respiratory tracts, and cardiovascular system. Food allergy is a leading cause of anaphylaxis and, therefore, referral to an allergist for appropriate and timely diagnosis and treatment is imperative. Diagnosis involves a careful history and diagnostic tests, such as skin prick testing, serum-specific immunoglobulin E (IgE) testing and, if indicated, oral food challenges. Once the diagnosis of food allergy is confirmed, strict elimination of the offending food allergen from the diet is generally necessary. For patients with significant systemic symptoms, the treatment of choice is epinephrine administered by intramuscular injection into the lateral thigh. Although most children "outgrow" allergies to milk, egg, soy and wheat, allergies to peanut, tree nuts, fish and shellfish are often lifelong. This article provides an overview of the epidemiology, pathophysiology, diagnosis, management and prognosis of patients with food allergy.

An introduction to immunology and immunopathology.

In basic terms, the immune system has two lines of defense: innate immunity and adaptive immunity. Innate immunity is the first immunological, non-specific (antigen-independent) mechanism for fighting against an intruding pathogen. It is a rapid immune response, occurring within minutes or hours after aggression, that has no immunologic memory. Adaptive immunity, on the other hand, is antigen-dependent and antigen-specific; it has the capacity for memory, which enables the host to mount a more rapid and efficient immune response upon subsequent exposure to the antigen. There is a great deal of synergy between the adaptive immune system and its innate counterpart, and defects in either system can provoke illness or disease, such as autoimmune diseases, immunodeficiency disorders and hypersensitivity reactions. This article provides a practical overview of innate and adaptive immunity, and describes how these host defense mechanisms are involved in both health and illness.

Community Use of Epinephrine for the Treatment of Anaphylaxis: A Review and Meta-Analysis.

BACKGROUND: Community use of epinephrine for the treatment of anaphylaxis is low. Knowledge of rates of epinephrine use in the pre-hospital setting along with identification of barriers to its use will contribute to the development of policies and guidelines. OBJECTIVES: A search was conducted on PubMed and Embase in April 2020. Our systematic review focused on 4 domains: (1) epinephrine use in the pre-hospital setting; (2) barriers to epinephrine use in the pre-hospital setting; (3) cost evaluation and cost-effectiveness of epinephrine use; and (4) programs and strategies to improve epinephrine use during anaphylaxis. METHODS: Two meta-analyses with logit transformation were conducted to: (1) calculate the pooled estimate of the rate of epinephrine use in the pre-hospital setting among cases of anaphylaxis and (2) calculate the pooled estimate of the rate of biphasic reactions among all cases of anaphylaxis. RESULTS: Epinephrine use in the pre-hospital setting was significantly higher for children compared with adults (20.98% [95% confidence interval (CI): 16.38%, 26.46%] vs 7.17% [95% CI: 2.71%, 17.63%], respectively, P = .0027). The pooled estimate of biphasic reactions among all anaphylaxis cases was 3.92% (95% CI: 2.88%, 5.32%). Our main findings indicate that pre-hospital use of epinephrine in anaphylaxis remains suboptimal. Major barriers to the use of epinephrine were identified as low prescription rates of epinephrine autoinjectors and lack of stock epinephrine in schools, which was determined to be cost-effective. Finally, in reviewing programs and strategies, numerous studies have engineered effective methods to promote adequate and timely use of epinephrine. CONCLUSION: The main findings of our study demonstrated that across the globe, prompt epinephrine use in cases of anaphylaxis remains suboptimal. For practical recommendations, we would suggest considering stock epinephrine in schools and food courts to increase the use of epinephrine in the community. We recommend use of pamphlets in public areas (ie, malls, food courts, etc.) to assist in recognizing anaphylaxis and after that with prompt epinephrine administration, to avoid the rare risk of fatality in anaphylaxis cases.

Elevated cord blood IgE is associated with recurrent wheeze and atopy at 7 yrs in a high risk cohort.

There is considerable interest in identifying children at high risk for developing atopic diseases for primary prevention. This study evaluates risk factors for detectable cord blood IgE and assesses CB-IgE in predicting asthma and other IgE-mediated allergic diseases in children at high risk because of family history. Cord blood was obtained as part of a randomized controlled trial assessing the efficacy of an intervention program in the primary prevention of IgE-mediated allergic diseases. CB-IgE was measured and the degree to which this was associated with perinatal risk factors was assessed. The cohort was then evaluated for atopic disorders at 7 yrs of age to assess the predictive value of CB-IgE. Fifty-five (19.3%) of infants had detectable CB-IgE (>/=0.5 kU/l). Maternal atopy and birth in winter months were risk factors associated with detectable CB-IgE. CB-IgE was found to be significantly associated with allergic sensitization (OR 2.22; 95% CI 1.11, 4.41) and recurrent wheeze at 7 yrs (OR 2.51, 95% CI 1.09, 5.76) but not with other outcomes. CB-IgE may be a useful measure for identifying children at high risk of atopic diseases for the purpose of primary prevention.