Aeroallergen sensitization and allergic disease phenotypes in Asia.

Allergic diseases are on the rise in Asia. Aeroallergen exposure is a strong risk factor for sensitization, development and severity of atopic diseases, especially in the Asian paediatric population. Geographical and seasonal variations in aeroallergen sensitization are seen even within Asian countries and changes in aeroallergen sensitization patterns have been observed over time. Some possible reasons include climate change as well as rapid urbanization and improved sanitation which follow socioeconomic development. House dust mite allergy is present in up to 90% of Asian atopic patients, far exceeding that which is seen in Western populations which report prevalences of only 50% to 70%. Pollen and animal dander affect less than 10% of Asian patients as compared to 40-70% of individuals with asthma and allergic rhinitis living in the West, a burden almost equivalent to the dust mite burden in those regions. There is thus a pressing need for preventive measures to reduce dust mite sensitization in Asian children today.

Use of intravenous immunoglobulin in an Asian paediatric population over a 10-year period.

AIMS: There is a paucity of data on the pattern of intravenous immunoglobulin (IVIG) usage in the paediatric population. This study aimed to assess the prevalence, trends, indications and burden of cost of IVIG usage in the Singaporean paediatric population. METHODS: Pharmacy data of all IVIG prescriptions between 2000 and 2009 in the two major paediatric public hospitals in Singapore were retrospectively reviewed. Each prescription was cross-referenced with the patient's hospital records to confirm the administration of IVIG and indication of use. RESULTS: Over the 10-year period, a total 78,155 g of IVIG valued at an estimated $5.2 million was prescribed. There was an increasing trend of 445.6 g/year (P = 0.02) over this period. Analysis of patients showed that the most common indication for IVIG use was Kawasaki disease, both in terms of the proportion of patients (60%) and amount of IVIG used (34%). Kawasaki disease was also the only indication where there were significant increasing trends in both patient numbers (7.4 patients/year) and amount of IVIG used (247.5 g/year). The indications with the highest amount of IVIG used per patient were for conditions related to primary immunodeficiency diseases and stem cell transplantation, where repeat transfusions were required. More than 75% of indications were Food and Drug Administration approved. CONCLUSION: Albeit substantial and increasing, the use of IVIG in Singaporean children is mostly evidence based.

Shellfish allergy--an Asia-Pacific perspective.

BACKGROUND AND OBJECTIVE: Shellfish forms a common food source in the Asia-Pacific and is also growing in the West. This review aims to summarize the current literature on the epidemiology and research on shellfish allergy with particular focus on studies emerging from the Asia-Pacific region. DATA SOURCES: A PubMed search using search strategies "Shellfish AND Allergy", "Shellfish Allergy Asia", and "Shellfish AND anaphylaxis" was made. In all, 244 articles written in English were reviewed. RESULTS: Shellfish allergy in the Asia-Pacific ranks among the highest in the world and is the most common cause of food-induced anaphylaxis. Shellfish are classified into molluscs and arthropods. Of the arthropods, the crustaceans in particular Penaeid prawns are the most common cause of allergy and are therefore most extensively studied. Several classes of allergens have been identified. The tropomyosins (class 1 allergens) are the best defined. Despite the establishment of molecular homology and allergenic cross reactivity between allergens of the same class, clinical cross-reactivity is more variable between patients and less clearly defined. There are two relatively unique clinical manifestations of IgE-mediated prawn allergy: (1) isolated oral allergy symptoms; and (2) wide spectrum of severity and sometimes even within the same individual. CONCLUSION: Shellfish allergy is common in the Asia Pacific. More research including food challenge-proven subjects are required to establish the true prevalence, as well as to understand clinical cross reactivity and variations in clinical features.

Prevalence of IgE-mediated cow milk, egg, and peanut allergy in young Singapore children.

Background: The rising prevalence of food allergy reported in the United States, UK, and Australia may be attributable to the rise in peanut allergy prevalence. The food allergy prevalence in other parts of the world such as Asia is, however, less well documented. Objective: This study aimed to evaluate the prevalence of cow's milk, egg, and peanut allergies in a general population of Singaporean children below 30 months of age. Methods: A total of 4,115 children from the general population who attended well-baby visits between 2011 and 2015 completed standardized questionnaires to elicit a convincing history of food allergy to estimate the population prevalence of food allergies. Results: The prevalence of a convincing history of cow's milk allergy was 0.51% (95% confidence interval [CI], 0.3-0.7), hen's egg allergy 1.43% (95% CI, 1.1-1.8), and peanut allergy 0.27% (95% CI, 0.12-0.42). Of the 15 of 59 children with a convincing history of hen's egg allergy who consented, 12 (80%) had corroborative positive skin prick tests. Conclusion: The prevalence of food allergy, in particular peanut allergy, in children below 2 years of age is lower in this South East Asian population than reported in Western cohorts. Further research should focus on deciphering differential risk factors for food allergy across different geographical locations.

Simulating inadequate dialysis and its correction using an individualized patient-derived nomogram.

Computerized kinetic modeling is a valuable automated peritoneal dialysis (APD) prescription tool for optimizing dialysis adequacy. However, non-compliance results in failure to achieve adequacy targets. The aim of this study was to determine if a nomogram could estimate dialysis compensations for shortfalls in simulated non-compliant patients, such that total weekly urea clearance (Kt/V(urea)) targets are met. Individualized nomograms comprising a series of curves were derived from PD Adequest (ver. 2.0)-predicted Kt/V(urea) data (r (2 ) > 0.99) for different APD prescriptions. The nomogram was then used to estimate the (Nomogram-computed) average of the daily Kt/V(urea) in 14 patients. The study comprised three 1-month phases. Patients were compliant to dialysis in phase I, where Adequest-predicted Kt/V(urea) showed good agreement with both measured (r (I) = 0.72), and Nomogram-computed values (r (I) > 0.99) (p < 0.001). Conversely, in non-compliant phase II, Nomogram-computed values were lower than Adequest-predicted values (p < 0.002). In phase III, the nomogram estimated prescription adjustments required to compensate for shortfalls, such that there was significantly less difference between Nomogram-computed and Adequest-predicted Kt/V(urea) than in phase II (p = 0.005). Thus, despite non-compliance, predicted Kt/V(urea) targets were attained using the nomogram to adjust the daily APD prescriptions. This concept is potentially useful for patients desiring to compensate for inadvertent shortfalls, rather than for 'truly non-compliant' patients.

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.

Food allergy in Asia: how does it compare?

Asia is a populous and diverse region and potentially an important source of information on food allergy. This review aims to summarize the current literature on food allergy from this region, comparing it with western populations. A PubMed search using strategies "Food allergy AND Asia", "Food anaphylaxis AND Asia", and "Food allergy AND each Asian country" was made. Overall, 53 articles, published between 2005 and 2012, mainly written in English were reviewed. The overall prevalence of food allergy in Asia is somewhat comparable to the West. However, the types of food allergy differ in order of relevance. Shellfish is the most common food allergen from Asia, in part due to the abundance of seafood in this region. It is unique as symptoms vary widely from oral symptoms to anaphylaxis for the same individual. Data suggest that house dust mite tropomysin may be a primary sensitizer. In contrast, peanut prevalence in Asia is extremely low compared to the West for reasons not yet understood. Among young children and infants, egg and cow's milk allergy are the two most common food allergies, with prevalence data comparable to western populations. Differences also exist within Asia. Wheat allergy, though uncommon in most Asian countries, is the most common cause of anaphylaxis in Japan and Korea, and is increasing in Thailand. Current food allergy data from Asia highlights important differences between East and West, and within the Asian region. Further work is needed to provide insight on the environmental risk factors accounting for these differences.

Stem cell transplantation for primary immunodeficiency disease: experience of a singapore hospital.

We retrospectively analyzed the outcomes of hematopoietic stem cell transplantation in 7 patients with primary immunodeficiency diseases treated at the National University Hospital, Singapore, over the period from December 1996 to January 2010. The primary immunodeficiency diseases managed were X-linked hyperimmunoglobulin M syndrome (n = 3), severe combined immunodeficiency (n = 1), leukocyte adhesion deficiency type 1 (n = 1), chronic granulomatous disease (n = 1), and Wiskott-Aldrich syndrome (n = 1). The age of the patients ranged from 5 months to 17 years. Conditioning regimen depended on the type of immunodeficiency, whereas supportive treatment was tailored for differing pretransplant conditions. Eight stem cell transplantations were performed for 7 patients. Donors were HLA-matched sibling donors for 2 patients and unrelated donors for the rest. At the median follow-up of 8.6 years (range 2.2-15.0 years) as of December 2011, 6 patients were alive and cured of their primary diseases.