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.

Asia Pacific Association of Allergy Asthma and Clinical Immunology White Paper 2020 on climate change, air pollution, and biodiversity in Asia-Pacific and impact on allergic diseases

Air pollution, climate change, and reduced biodiversity are major threats to human health with detrimental effects on a variety of chronic noncommunicable diseases in particular respiratory and cardiovascular diseases. The extent of air pollution both outdoor and indoor air pollution and climate change including global warming is increasing-to alarming proportions particularly in the developing world especially rapidly industrializing countries worldwide. In recent years, Asia has experienced rapid economic growth and a deteriorating environment and increase in allergic diseases to epidemic proportions. Air pollutant levels in many Asian countries especially in China and India are substantially higher than are those in developed countries. Moreover, industrial, traffic-related, and household biomass combustion, indoor pollutants from chemicals and tobacco are major sources of air pollutants, with increasing burden on respiratory allergies. Here we highlight the major components of outdoor and indoor air pollutants and their impacts on respiratory allergies associated with asthma and allergic rhinitis in the Asia-Pacific region. With Asia-Pacific comprising more than half of the world's population there is an urgent need to increase public awareness, highlight targets for interventions, public advocacy and a call to action to policy makers to implement policy changes towards reducing air pollution with interventions at a population-based level.

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.

Growth of children with food allergies in Singapore

BACKGROUND: Although it is known that children with food allergies are at risk of impaired growth, this has not been well studied in South-East Asia. OBJECTIVE: The aim of this cross-sectional study is to survey the growth of children with food allergies in Singapore and the factors impacting it. METHODS: Anthropometric data, demographic data, type of food allergy, foods eliminated, and atopic comorbidities were recorded. Malnutrition was defined using World Health Organization standards (≤-2 z-score for weight-for-height [WH], weight-for-age [WA], and height-for-age [HA]).

Cashew nut allergy in Singaporean children

BACKGROUND: There has been an increasing trend of nut allergies in Singapore. OBJECTIVE: The aim of this study was to review the clinical characteristics of children with cashew nut allergy. METHODS: A retrospective analysis was conducted in a tertiary paediatric referral centre in Singapore from 2008 to 2015. A total of 99 subjects with positive specific IgE (≥0.35 IU/L) to cashew nut were identified. Clinical features including demographics, clinical reaction to cashew nut, associations with other nuts and test specific measurements were recorded. RESULTS: The results showed that cutaneous symptoms (71.2%) were the most common allergic manifestations. Anaphylaxis occurred in 3.8% of children. In addition, all cashew nut allergic subjects were cross-reactive (either sensitized or allergic) to pistachio. Cross-reactivity rate with peanuts was 53.8%. There was a strong prevalence of atopy among cashew nut allergic subjects. CONCLUSION: In conclusion, cashew nut allergy is a significant tree nut allergy in Singapore.

Relationship between all fevers or fever after vaccination, and atopy and atopic disorders at 18 and 36 months

BACKGROUND: Studies have reported that early febrile episodes and febrile episodes with infections are associated with a decreased risk of developing atopy. OBJECTIVE: To examine further the association between presence of and number of febrile episodes are with atopy and atopic diseases and if there was a difference between all fevers and fever after vaccination. METHODS: We studied 448 infants in a Singapore mother-offspring cohort study (Growing Up in Singapore Towards Healthy Outcomes) which had complete data for the exposures and outcomes of interest. Fever was defined as more than 38.0℃ and was self-reported. The presence of and number of febrile episodes were examined for association with outcome measures, namely parental reports of doctor-diagnosed asthma and eczema, and rhinitis, which was evaluated by doctors involved in the study at 18 and 36 months. These outcomes were considered atopic if there were 1 or more positive skin prick tests. RESULTS: The presence of all fevers from 0–6 months of age was associated with reduced odds of having atopy at 36 months of age (unadjusted odds ratio [OR], 0.628; 95% confidence interval [CI], 0.396–0.995). The presence of fever after vaccination from 0–24 months of age was associated with reduced odds of having atopy at 36 months of age (OR, 0.566; 95% CI, 0.350–0.915). The presence of all fevers from 0–6 months of age was associated with reduced odds of having atopic eczema at 36 months (OR, 0.430; 95% CI, 0.191–0.970). Fever was associated with increased odds of having doctor-diagnosed asthma and rhinitis. CONCLUSION: There was an inverse relationship between the presence of all fevers from 0–6 months of age and the development of atopy and eczema at 36 months of age. Fever after vaccination might be considered a subclinical infection that did not show the same effect in early life.

Pilot study of the use of Yin Qiao San in children with conventional antipyretic hypersensitivity

BACKGROUND: Children with a diagnosis of cross-reactive hypersensitivity to both paracetamol and nonsteroidal anti-inflammatory drugs are limited in their choice of antipyretics. OBJECTIVE: The aim of this pilot study is to evaluate the feasibility of using a Chinese proprietary medicine, Yin Qiao San (YQS), for fever relief. METHODS: A single centre, open label, prospective clinical trial exploring the tolerability and feasibility of using YQS for fever relief in children who are unable to use conventional antipyretic medications. Children between 1-18 years of age with hypersensitivity to multiple antipyretics were recruited. Eligible participants underwent an oral provocation test with YQS. Children who passed the oral provocation test were instructed to take a prescribed dose of YQS when the temperature was >38.0℃ and continued till the fever settled. Time taken for fever resolution and any adverse events were collected. RESULTS: A total of 21 children, mean age 10.7 years, had a diagnosis of paracetamol and ibuprofen hypersensitivity. All except one patient successfully tolerated an oral challenge of YQS. Of the 88 doses of YQS taken for fever over 38.0℃, 16 (18%) had documented temperature reduction 2 hours after ingestion and 30 (34%) had documented temperature reduction 4 hours after ingestion. There were 2 reports of urticaria after YQS use which were attributed to flare of recurrent spontaneous urticaria during the illness. None of the patients developed symptoms of circulatory compromise or respiratory distress. CONCLUSION: YQS is generally well tolerated in patients with paracetamol and ibuprofen hypersensitivity.

Tolerance to etoricoxib in children with nonsteroidal anti-inflammatory drug hypersensitivity

BACKGROUND: Cyclooxygenase-2 (COX-2) inhibitors have been found to be safe alternatives in adults with cross-intolerant hypersensitivity to nonsteroidal anti-inflammatory drugs (NSAIDs). However they are usually not prescribed in children and there is little information about their tolerance in the pediatric age group. OBJECTIVE: This study aims to evaluate the tolerance to etoricoxib in children with hypersensitivity to multiple antipyretics. METHODS: A retrospective case series of children diagnosed with hypersensitivity reactions to NSAIDs and/or paracetamol who underwent a drug provocation test (DPT) with etoricoxib. Information on atopy, family history of allergic diseases, and medication usage was collected. Outcomes of the DPTs and tolerance to etoricoxib were also evaluated. RESULTS: A total of 24 children, mean age 13.5 years, had a diagnosis of cross-intolerant hypersensitivity to NSAIDs and/or paracetamol. All except one patient successfully tolerated an oral challenge with etoricoxib. Of those who passed the DPT, the majority continued to use etoricoxib with no problems. It was found to be moderately effective in reducing fever and pain. CONCLUSION: Etoricoxib can be used as a safe alternative in older children with hypersensitivity to multiple antipyretics.

Gum pigmentation: an unusual adverse effect of sublingual immunotherapy

Sublingual immunotherapy has gained acceptance amongst the paediatric community as it is very well tolerated and is safe. The adverse effects of this therapy is minimal consisting mainly of local side effects within the oral cavity such as itching of the mouth, swelling of the lips and less frequently abdominal pain, wheezing and urticaria has been described. This report is to highlight another local side effect of sublingual immunotherapy which has been observed in 3 of our patients. This is pigmentation of the gums which can occur anytime during the course of the immunotherapy. It resolves on stopping the immunotherapy and is likely due to a local inflammatory process occurring in the gums of these children. There is no associated pain or itching with the pigmentation. It can persist as long as the child is on the immunotherapy.

Compliance with noninvasive home ventilation in children with obstructive sleep apnoea

<p><b>INTRODUCTION</b>This study aimed to determine compliance with noninvasive home ventilation in children with obstructive sleep apnoea and the factors affecting this compliance.</p><p><b>METHODS</b>We retrospectively reviewed 51 children who were prescribed noninvasive home ventilation for the management of obstructive sleep apnoea from 1 January 2000 until 31 May 2008. Noninvasive ventilation was started based on positive polysomnogram, i.e. obstructive apnoea hypopnea index ≥ 1/hr. Compliance was defined as the use of noninvasive ventilation ≥ 4 days/week.</p><p><b>RESULTS</b>Noninvasive home ventilation was started at a median age of 11.5 years. In all, 21 (41.2 %) children were reported to be compliant with treatment. Univariate analysis revealed that the female gender (p = 0.017), presence of asthma (p = 0.023), presence of genetic syndromes (p = 0.023), use of bi-level ventilation versus continuous positive airway pressure (p = 0.027), and funding from the social work department (p = 0.049) were associated with compliance with noninvasive home ventilation. Logistic regression revealed the presence of asthma (p = 0.008) and female gender (p = 0.047) to be significantly associated with compliance with treatment. However, factors such as counselling prior to initiation of treatment, severity of obstructive sleep apnoea before initiation of treatment, obesity, use of humidification, and polysomnogram indices were not found to be associated with treatment compliance.</p><p><b>CONCLUSION</b>Only 41.2% of the children in this study were reported to be compliant with noninvasive home ventilation. The female gender and the presence of asthma were associated with treatment compliance. Future research focusing on effective methods to improve compliance with noninvasive home ventilation in children should be undertaken.</p>

The methodology of the GUSTO cohort study: a novel approach in studying pediatric allergy

Growing Up in Singapore Towards healthy Outcomes (GUSTO) is Singapore's largest birth cohort study to date. The main aim of GUSTO is to evaluate the role of developmental factors in the early pathways to metabolic compromise. Detailed data is collected for a range of environmental exposures in the parents and offspring, and allergic disorders are among a number of outcomes assessed in infancy and childhood. Under the Allergy domain of GUSTO, this integrated study will describe the epidemiology of allergic manifestations and different phenotypes in the Asian context and help shed light on the association of metabolic disease to allergy. Epigenetic mechanisms and associations with other childhood disorders will also be explored. The aim of this report is to focus on methodology of GUSTO, and to suggest similar approaches (i.e., integrated cohort studies on pediatric allergy) worldwide. Recruitment commenced in 2009 with a cohort of 1,163 pregnant mothers in their first trimester. The mothers and children were followed throughout pregnancy and follow-up will continue until the child reaches 3 years of age. Preliminary results showed that 39.8% of the mothers had a personal history of having at least one allergic disease, which included asthma, eczema and allergic rhinitis. Further data collection and analyses are still ongoing. Allergy is a complex spectrum of disorders with numerous poorly-understood aspects. The ongoing GUSTO cohort study, with its longitudinal design and multi-disciplinary nature, may provide new insights into developmental influences on allergy. As a Singapore-based study, it will be the first integrated allergy cohort in Southeast Asia, of which recruitment started during pregnancy.

Childhood food allergy: a Singaporean perspective

Food allergy is defined as reaction to a food which has an immunologic mechanism. Its prevalence is increasing in children globally and is therefore of increasing clinical importance. A useful clinical approach is to distinguish food allergic reactions by the timing of clinical reaction in relation to food exposure and classified as immediate (generally IgE-mediated) and delayed (generally non-IgE-mediated), with the exception of eczema and eosinophilic gastrointestinal disease, which, when associated with food allergy may be associated with either mechanism. This review is aimed at providing the clinician with a Singaporean perspective on the clinical approach and management of these disorders.