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.

A stepwise approach in the management of chronic spontaneous urticaria in children

BACKGROUND: There is limited literature in the management of chronic urticaria in children. Treatment algorithms are generally extrapolated from adult studies. OBJECTIVE: Utility of a weight and age-based algorithm for antihistamines in management of chronic spontaneous urticaria (CSU) in childhood. To document associated factors that predict for step of control of CSU and time taken to attain control of symptoms in children. METHODS: A workgroup comprising of allergists, nurses, and pharmacists convened to develop a stepwise treatment algorithm in management of children with CSU. Sequential patients presenting to the paediatric allergy service with CSU were included in this observational, prospective study. RESULTS: Ninety-eight patients were recruited from September 2012 to September 2013. Majority were male, Chinese with median age 4 years 7 months. A third of patients with CSU had a family history of acute urticaria. Ten point two percent had previously resolved CSU, 25.5% had associated angioedema, and 53.1% had a history of atopy. A total of 96.9% of patients achieved control of symptoms, of which 91.8% achieved control with cetirizine. Fifty percent of all the patients were controlled on step 2 or higher. Forty-seven point eight percent of those on step 2 or higher were between 2 to 6 years of age compared to 32.6% and 19.6% who were 6 years and older and lesser than 2 years of age respectively. Eighty percent of those with previously resolved CSU required an increase to step 2 and above to achieve chronic urticaria control. CONCLUSION: We propose a weight- and age-based titration algorithm for different antihistamines for CSU in children using a stepwise approach to achieve control. This algorithm may improve the management and safety profile for paediatric CSU patients and allow for review in a more systematic manner for physicians dealing with CSU in children.

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.

Paediatric anaphylaxis in a Singaporean children cohort: changing food allergy triggers over time

BACKGROUND: We have noticed changes in paediatric anaphylaxis triggers locally in Singapore. OBJECTIVE: We aimed to describe the demographic characteristics, clinical features, causative agents and management of children presenting with anaphylaxis. METHODS: This is a retrospective study of Singaporean children presenting with anaphylaxis between January 2005 and December 2009 to a tertiary paediatric hospital. RESULTS: One hundred and eight cases of anaphylaxis in 98 children were included. Food was the commonest trigger (63%), followed by drugs (30%), whilst 7% were idiopathic. Peanut was the top food trigger (19%), followed by egg (12%), shellfish (10%) and bird's nest (10%). Ibuprofen was the commonest cause of drug induced anaphylaxis (50%), followed by paracetamol (15%) and other nonsteroidal anti-inflammatory drugs (NSAIDs, 12%). The median age of presentation for all anaphylaxis cases was 7.9 years old (interquartile range 3.6 to 10.8 years), but food triggers occurred significantly earlier compared to drugs (median 4.9 years vs. 10.5 years, p < 0.05). Mucocutaneous (91%) and respiratory features (88%) were the principal presenting symptoms. Drug anaphylaxis was more likely to result in hypotension compared to food anaphylaxis (21.9% vs. 2.7%, Fisher's exact probability < 0.01). There were 4 reported cases (3.6%) of biphasic reaction occurring within 24 h of anaphylaxis. CONCLUSION: Food anaphylaxis patterns have changed over time in our study cohort of Singaporean children. Peanuts allergy, almost absent a decade ago, is currently the top food trigger, whilst seafood and bird's nest continue to be an important cause of food anaphylaxis locally. NSAIDs and paracetamol hypersensitivity are unique causes of drug induced anaphylaxis locally.

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.