A 5-year retrospective review of children with peanut allergy in the largest paediatric hospital in Singapore

BACKGROUND: The prevalence of peanut allergy (PA) among children has increased significantly over the past decade. Even though the prevalence of PA in Singapore is considered low, peanut is the top trigger for food-induced anaphylaxis in Singaporean children.OBJECTIVE: To describe the demographic characteristics and clinical features of children with PA.METHODS: This is a 5-year retrospective review of children diagnosed with PA based on clinical history coupled with a positive skin prick test to peanut or positive oral food challenge results.RESULTS: There were 269 patients (53.9% males) with a clinical diagnosis of PA. The median age at first allergic presentation for the PA group was 24 months old, with interquartile range of 13–39 months. The most common form of peanut introduced was roasted peanut. The rate of peanut anaphylaxis was 7.1%. Concomitant tree nut sensitization was found in 32.3% of this cohort, predominantly to cashew nut. Majority of them have a personal history of atopy – 75.8% with eczema, 63.6% with allergic rhinitis, and 19.7% with asthma.CONCLUSION: This is the first large review of peanut-allergic children in Singapore. Prospective population-based studies are needed to establish the true prevalence and risk factors associated with the development of this potentially life-threatening condition.

Predictive value of peanut skin prick test, specific IgE in peanut-sensitized children in Singapore

BACKGROUND: The predictive decision points for both peanut skin prick test (SPT) wheal size and serum IgE concentrations, in peanut-sensitized children, have not been evaluated in Singapore. OBJECTIVE: We aim to derive clinically useful predictive decision points to be used for risk stratification of oral food challenge (OFC) in peanut-sensitized patients. METHODS: Patients with a positive SPT to peanut, performed during a 4-year period between 2012 and 2016, were included in a retrospective chart review. The patients were assessed for their peanut allergy status based on a convincing clinical history. Their first SPT and serum IgE results done at presentation to our centre were used. RESULTS: There were 269 patients with a clinical diagnosis of peanut allergy based on recent immediate reaction to peanut and 59 patients whom were tolerating peanuts regularly. There were 251 patients sensitized to peanut, without prior known peanut exposure. A wheal size of ≥8 mm and a peanut-specific IgE of ≥6 kU/L each provided for a 95% positive predictive value of clinical reaction to peanuts; the larger the wheal size on SPT, the higher the probability. CONCLUSION: The cutoff values derived in this study can help clinicians in the risk assessment of OFC in peanut-sensitized patients. Prospective studies using OFCs for the diagnosis of peanut allergy are needed to confirm the diagnostic performance of these tests in predicting OFC outcomes.

Efficacy and safety of oral immunotherapy for peanut allergy: a pilot study in Singaporean children

BACKGROUND: Peanut allergy is an increasing problem in Singapore and strict avoidance is difficult as peanut is ubiquitous in Asian cuisine. OBJECTIVE: We aimed to assess the efficacy and safety of peanut oral immunotherapy (OIT) in children with obvious peanut allergy in Singapore. METHODS: This was an open-label study of peanut OIT in children living in Singapore, with 2 weekly dose escalation until final maintenance dose of 3,000 mg of peanut protein and a maintenance phase of 12 months. An oral food challenge was performed at 6 months to assess for desensitisation and at 4 weeks after discontinuation of OIT having completed 12 months of maintenance therapy to assess for possible sustained unresponsiveness. The adverse events were monitored using the symptom diaries. RESULTS: Nine subjects were started on OIT, with 7 managing to complete maintenance phase of therapy. Of these 7, all were able to tolerate at least 3,000 mg of peanut protein by 6 months of maintenance therapy, showing that the OIT was effective. Of these 7, 3 patients complied with the 4-week abstinence period after completion of OIT before another peanut challenge; 2 of the 3 subjects showed a significant decrease from the initial ability to tolerate 3,000 mg of peanut protein. Side effects were mainly gastrointestinal in nature and were more common during the updosing phase than the maintenance phase. No episodes of anaphylaxis were observed in this study. CONCLUSION: Peanut OIT seemed to be effective and safe in our cohort of Singaporean children.

Achados epidemiológicos de alergia alimentar em crianças brasileiras: análise de 234 testes de provocação duplo-cego placebo-controlado (TPDCPCs) / Epidemiological findings in food allergic Brazilian children: an analysis of 234 double-blind placebo-controlled food challenge (DBPCFC) tests

Introdução: Os dados sobre prevalência de alergia alimentar são escassos e limitados no Brasil. Este trabalho objetiva descrever as características clínicas de crianças brasileiras com alergia alimentar diagnosticada através de teste de provocação duplo-cego placebo-controlado (TPDCPC). Métodos: Dos pacientes avaliados, foram selecionadas, de forma prospectiva, no Ambulatório de Alergia e Pneumologia Pediátrica, 234 crianças com suspeita clínica de alergia alimentar e teste alérgico positivo para alimento, no período de 1993 a 2005. Para confirmar o diagnóstico de alergia alimentar, foram realizados TPDCPCs com o alimento suspeito. Resultados: Dos 234 TPDCPCs realizados, 30 foram positivos (12,8%), sendo mais frequentes em crianças abaixo de dois anos e do sexo masculino. Dos testes positivos, 26 (86,6%) foram positivos para ovo ou leite de vaca. Pacientes com diagnóstico inicial de dermatite atópica ou alergia gastrointestinal apresentaram TPDCPC positivo mais frequentemente do que pacientes com sintomas respiratórios. Entre os sintomas apresentados durante o TPDCPC, prevaleceram os sintomas cutâneos (60%) e respiratórios (56,67%). Conclusão: A incidência de alergia alimentar na população com suspeita clínica foi de 12,8%. Leite de vaca e ovo são os principais alimentos responsáveis pela alergia alimentar em nosso meio, que é mais frequente em crianças abaixo de dois anos. O teste alérgico positivo é um fraco preditor de alergia alimentar (VPP = 13,5%), mas o teste alérgico negativo praticamente afasta o diagnóstico, pois o seu valor preditivo negativo na população estudada foi próximo de 100%.

Introduction: Data on the prevalence of food allergy are scarce and limited in Brazil. This work aims to describe the clinical characteristics of Brazilian children with food allergy, diagnosed through the Double-Blind Placebo-Controlled Food Challenge (DBPCFC). Methods: Of the evaluated patients, 234 children with clinical suspicion of food allergy and positive food allergy test between 1993 and 2005 were selected prospectively in a Pediatric Allergy and Pneumology Clinic. In order to confirm the diagnosis of food allergy, the DBPCFC was used with suspected allergenic food. Results: Of the 234 TPDCPCs performed, 30 tests were positive (12.8%), more frequently in children less than two years old and male sex. Of these positive tests, 26 (86.6%) were positive for eggs or cow's milk. Patients with initial diagnosis of atopic dermatitis or gastrointestinal allergy had a positive TPDCPC more frequently than patients with respiratory symptoms. Among the symptoms presented during the TPDCPC, cutaneous (60%) and respiratory symptoms (56.67%) prevailed. Conclusion: The incidence of food allergy in the clinically suspected population was 12.8%. Cow's milk and eggs are the main foods responsible for food allergy in our setting, and they are more common in children less than two years old. A positive allergic test is a poor predictor of food allergy (PPV = 13.5%), but a negative allergic test virtually eliminates this diagnosis, as its negative predictive value in the studied population was close to 100%.

Diagnostic Value of Specific IgE to Peanut and Ara h 2 in Korean Children with Peanut Allergy

PURPOSE: The purpose of this study was to establish the diagnostic decision point (DDP) of peanut specific IgE (sIgE) for predicting the outcome of oral food challenge (OFC). We also evaluated the usefulness of sIgE to peanut components (Ara h 1, 2, 3, 8, and 9) in diagnosing peanut allergy. METHODS: Korean children aged over 12 months with a suspected peanut allergy were enrolled. Diagnosis of peanut allergy was confirmed by an open OFC or through the convincing history of anaphylaxis. Cutoff levels of sIgE to peanut and peanut components were determined by analyzing receiver operating characteristic curves. RESULTS: Forty-eight children (22 boys and 26 girls) with a suspected peanut allergy were enrolled. The previously established DDP for peanut-sIgE antibodies (14 kU/L) showed a sensitivity of 22.7%, specificity of 100%, positive predictive value (PPV) of 100%, and negative predictive value of 60.4% in our study population. The median levels of peanut-sIgE (5.4 kU/L vs 1.1 kU/L, P<0.001) and Ara h 2-sIgE (0.8 kU/L vs 0 kU/L, P<0.001) were significantly higher in the peanut allergy group than in the peanut tolerance group. The peanut-sIgE concentration indicating a PPV of 100% was 10.3 kU/L. The Ara h 2-sIgE level of 4.0 kU/L had a PPV of 100%. CONCLUSIONS: Our results showed that the cutoff levels for peanut (10.3 kU/L) and Ara h 2 (4.0 kU/L) established in this study is useful for the diagnosis of peanut allergy in Korean children.

Clinical Significance of Component Allergens in Fagales Pollen-Sensitized Peanut Allergy in Korea

PURPOSE: Clinical features of peanut allergy can range from localized to systemic reactions. Because peanut and birch pollen have cross-reactivity, peanut can lead to localized allergic reaction in Fagales pollen-sensitized oral allergy syndrome (OAS) patients without peanut sensitization per se. The purpose of this study was to discriminate true peanut food allergy from cross-reactive hypersensitivity in birch-sensitized peanut allergy. METHODS: Birch-sensitized (n=81) and peanut anaphylaxis patients (n=12) were enrolled. Peanut-related allergic reactions and sensitization profiles were examined. Specific IgE to Fagales tree pollens (birch, oak), peanut, and their component allergens (Bet v 1, Bet v 2, Ara h 1, Ara h 2, Ara h 3, Ara h 8, and Ara h 9) were evaluated. Based on these specific IgEs and clinical features, the patients were classified into 4 groups: group 1 (Fagales pollen allergy without OAS), group 2 (Fagales pollen allergy with OAS), group 3 (OAS with peanut anaphylaxis), and group 4 (peanut anaphylaxis). RESULTS: After peanut consumption, one-third of OAS patients experienced oral symptoms not associated with peanut sensitization. Ara h 1 or Ara h 2 was positive in peanut anaphylaxis patients, whereas Ara h 8 was positive in OAS patients. There were 4 patients with both peanut anaphylaxis and OAS (group 3). Both Ara h 2 and Ara h 8 were positive in these patients. Foods associated with OAS in Korea showed unique patterns compared to Westernized countries. CONCLUSIONS: Ara h 2 and Ara h 8 may be important component allergens for discriminating peanut allergy.

Repeat oral food challenges in peanut and tree nut allergic children with a history of mild/moderate reactions

BACKGROUND: In peanut and tree nut allergic children a history of anaphylaxis is associated with subsequent severe reactions. OBJECTIVE: We aimed to prospectively rechallenge peanut and tree nut allergic children with a history of mild/moderate reactions to assess their allergy over time. METHODS: In this cohort study peanut and tree nut allergic children with a history of mild/moderate reactions during a controlled oral challenge were invited to have a follow-up oral challenge to the same food at least 1 year later. RESULTS: Twenty-six children participated in the study. The mean time interval between the first and second challenge for all participants was 35.5 months. Peanut or tree nut allergy resolved in 38.5% of participants. Those with persistent peanut or tree nut allergy showed a decrease in their reaction threshold and/or increased severity in 81% of cases. There were no demographic features or skin test results that were predictive of changes in severity over time. CONCLUSION: Peanut and tree nut allergic children with a history of mild/moderate reactions who remained allergic demonstrated a high rate of more severe reactions and/or reduced thresholds upon rechallenge over a year later, however, the rate of resolution of allergy in this group may be higher than previously reported.

Alergia alimentaria a maní: conceptos clínicos, diagnósticos y terapéuticos / Food allergy to peanuts: clinical, diagnostic and therapeutic concepts

The prevalence of food allergy (FA) is about 2-8 percent, with clinical manifestations ranging from localized symptoms, to severe anaphylactic reactions. FA is generally caused by milk, eggs, soybeans, tree nuts, peanuts, wheat, fish and crustacean; being peanut one of the main foods involved in Western countries. Although in other parts of the world peanut allergy (PA) is not a problem, probably due to timing of introduction into the diet, form and preparation, genetics, and the hygiene hypothesis. Unfortunately, in Chile there are no epidemiological data about FA or PA. A number of food allergens have been identified, which has improved patient diagnosis and treatment assessment. Regarding peanut, 9 allergens have been identified, Ara h 1 to Ara h 9 (Arachis hypogaea). The diagnosis of IgE-mediated PA is based on a consistent history and evidence of peanut-specific IgE sensitization, carried out by skin-prick testing or in vitro determination. PA treatment consists of peanuts avoidance, which often becomes difficult due to inadvertent consumption. Today promising treatments are under development, including oral induction tolerance or sublingual immunotherapy. These treatments offer the possibility of at least raising the threshold of the amount of peanut that would be necessary to cause a life-threatening allergic reaction.

Prevention of food allergy in infants: recommendation for infant feeding and complementary food introduction

Food allergy is common with the prevalence of 5%??% in Korean children. The development of food allergy is likely to reflect interactions between genetic factors and environmental exposure. To prevent food allergy, early exposure to food allergens through maternal and infant diet have been investigated. Recently, guidelines for primary prevention of food allergy have been updated, and consensus communication on early peanut introduction has been demonstrated. For the first 4?? months after birth, exclusive breast-feeding is recommended, and if impossible, extensively or partially hydrolyzed infant formula can be recommended in high-risk infants. Introducing complementary foods is recommended between 4 and 6 months of age, even in case of potentially allergenic foods such as egg, milk, and wheat. For the prevention of peanut allergy, early peanut introduction could be better than late peanut introduction in selected high-risk infants. However, infants who developed food allergy should avoid ingestion of specific offending foods.

Food allergy in Singapore: opening a new chapter

With the exception of shellfish, the overall food allergy rates in Singapore have not reached the epidemic proportions of the West. The rates of egg, milk and fish allergies remain low. However, the patterns of some food allergies in Singapore have changed over the last decade. For example, peanut allergy, once rare in Singapore, is now the most common cause of anaphylaxis in children. Studies analysing lifestyle practices, particularly with respect to prevention of food allergy, are necessary in order for practitioners to understand global differences and maintain this low prevalence.

Oral immunotherapy for the treatment of immediate type food allergy

Food allergies continue to increase exponentially and therapies that can modify the natural course of disease is a recent top priority of the research. IgE-mediated food allergy represents both a promising and an intriguing disease of application for allergen specific immunotherapy. In particular, oral immunotherapy (OIT) may offer a novel effective therapeutic modality for persistent and severe forms of food allergies. In such patients, avoidance of the causative foods only may be insufficient because of the risk of unplanned exposure to causative foods. In patients with cow's milk, hen's egg, and peanut allergies, several recently published studies, including meta-analysis, confirmed the overall benefit of OIT. However, the definitive evidence of efficacy and safety with long-term therapeutic or disease-modifying effects is limited. In current protocols, entry indications, and initial-escalating-maintenance doses, the form of antigens, durations, and follow-up periods await to be standardized. Most of the clinical trials of OIT demonstrate effective desensitization, but the ability for inducing long-term tolerance remains to be improved, and the ratio of risks versus benefits of OIT should be considered in detail. The ultimate goal is extending OIT to primary care practice, but at this time, OIT remains within the purview of allergy specialists in terms of associated risk-benefit ratios, related safety, and long-term tolerance induction.

Consumo de nozes e amendoim durante a gestação pode diminuir risco de doençasalérgicas em crianças / Consumption of nuts and peanuts during pregnancy may reduce risk of doençasalérgicas in children

Esse estudo não encontrou associação significativa entre oconsumo de amendoim e nozes na gravidez e aumento no riscode asma nas crianças. Na verdade, a ingestão materna de amendoime de nozes, pelo menos uma vez por semana durante agravidez, foi associada a risco significativamente reduzido deasma em seus filhos.

Alergia ao amendoim: revisão / Penaut allergy: review

Objetivo: Revisar a literatura para um melhor manejo do paciente com alergia a amendoim. Fonte de dados: Artigos originais indexados no banco de dados do MEDLINE no período de janeiro de 1990 a dezembro de 2011 nos idiomas português e inglês, além de sites específicos na Internet. Palavras-chave: alergia, atopia, amendoim, Arachis hypogaea. Síntese dos dados: O amendoim é um dos principais alimentos relacionados a manifestações alérgicas. Com início geralmente na infância, a alergia ao amendoim comumente associa-se a outras manifestações atópicas e à anafilaxia. O padrão ouro para diagnóstico permanece o teste de provocação oral, embora outros parâmetros imunológicos se mostrem promissores, como o diagnóstico resolvido por componentes (CRD-Component resolved diagnosis). Por determinar importante prejuízo na qualidade de vida destes pacientes e ser sua duração prolongada, na maioria dos casos, tem sido objeto de estudos de novas opções terapêuticas.Conclusões: Embora certamente o amendoim não se encontre entre os principais alimentos causadores de manifestações alérgicas observadas na prática clínica em nosso país, casos existem e é preciso saber o melhor manejo destes pacientes.

Objective: Review of the literature for a better handling of the patient with peanut allergy. Sources: English and Portuguese written original articles indexed on the MEDLINE databases from the period of January 1990 to December 2011 and also specific sites on the Internet. Key words: allergy, atopy, peanut, Arachis hypogaea. Data synthesis: Peanut is one of the main food allergy related sources. Beginning normally in childhood, peanut allergy is often associated with other atopic diseases and anaphylaxis. Oral food challenge remains the gold standard method for diagnosis although other immunological parameters, like component resolved diagnosis, seem promising. Accounting for an important impairment of the quality of life and long lasting symptoms, it is the objective of studies on new therapeutic options. Conclusions: Although certainly peanut is not one of the main food allergens in Brazil, there are cases and it is necessary knowing how to handle those.

Changes in Major Peanut Allergens Under Different pH Conditions

Regional dietary habits and cooking methods affect the prevalence of specific food allergies; therefore, we determined the effects of various pH conditions on major peanut allergens. Peanut kernels were soaked overnight in commercial vinegar (pH 2.3) or acetic acid solutions at pH 1.0, 3.0, or 5.0. Protein extracts from the sera of seven patients with peanut-specific IgE levels >15 kUA/L were analyzed by SDS-PAGE and immunolabeling. A densitometer was used to quantify and compare the allergenicity of each protein. The density of Ara h 1 was reduced by treatment with pH 1.0, 3.0, or 5.0 acetic acid, or commercial vinegar. Ara h 2 remained largely unchanged after treatment with pH 5.0 acetic acid, and was decreased following treatment with pH 1.0, 2.3, or 3.0 acetic acid. Ara h 3 and Ara h 6 appeared as a thick band after treatment with pH 1.0 acetic acid and commercial vinegar. IgE-binding intensities to Ara h 1, Ara h 2, and Ara h 3 were significantly reduced after treatment with pH 1.0 acetic acid or commercial vinegar. These data suggest that treatment with acetic acid at various pH values affects peanut allergenicity and may explain the low prevalence of peanut allergy in Korea.

Quercetin as a potential anti-allergic drug: which perspectives?

Flavonoids polyphenolic compounds that exert many anti-inflammatory and anti-microbial effects, and exhibit an anti-allergic action. Quercetin is a flavonoids that recently has raised many issues and shown evidence about its action as a potential drug to allergy. A Chinese herbal formula, known as Food Allergy Herbal Formula [FAHF] has been related with blocking of anaphylaxis to peanuts [PNA] in mouse models. Quercetin appears to possess the same potential of FAHF as a safe anti-allergic substance but it opens only a wide perspective, at the moment, due to several complex issues that hamper the possibility to use natural medicine and phytochemicals as true drugs

Avaliação das consequências da ingestão de semente de amendoim durante o período de desmame em camundongos isogênicos / Assessment of the consequences of the ingestion of peanut seed during the weaning isogenic

A penetração do antígeno pela mucosa intestinal pode resultar em duas situações distintas: a tolerância oral, onde se verifica uma redução na resposta imunológica sistêmica, e a alergia alimentar que é caracterizada pelo desenvolvimento de uma resposta imuno sistêmica para o antígeno em questão. As manifestações clínicas alérgicas de ambos os fenômenos são semelhantes e podem culminar na doença inflamatória intestinal em jovens e adultos. Baseado nestes achados, o objetivo principal foi avaliar se camundongos das linhagens Balb/c e C57BL/6 se tornariam sensíveis (alérgicos) para os antígenos do amendoim através da exposição oral...Os animais que receberam por via oral a semente de amendoim no período de perisdesmame não se sensibilizaram a esta proteína quando ofertada in natura no período de desafio oral na vida adulta.