Disparities in pediatric anaphylaxis triggers and management across Asia.

BACKGROUND: The epidemiology and management of anaphylaxis are not well-reported in Asia. METHODS: A regional pediatric anaphylaxis registry was established by the Asia-Pacific Research Network for Anaphylaxis (APRA), using standardized protocols for prospective data collection, to evaluate the triggers and management of anaphylaxis in the Asia-Pacific region. Pediatric patients below 18 years presenting with anaphylaxis across four Asian countries/cities (Thailand, Singapore, Hong Kong (HK), and Qingdao) were included. Allergen triggers, symptoms, anaphylaxis severity, and management were compared. RESULTS: Between 2019 and 2022, 721 anaphylaxis episodes in 689 patients from 16 centers were identified. The mean age at anaphylaxis presentation was 7.0 years (SD = 5.2) and 60% were male. Food was the most common trigger (62%), particularly eggs and cow's milk in children aged 3 years and below. In school-age children, nut anaphylaxis was most common in HK and Singapore, but was rare in the other countries, and wheat was the top allergen in Bangkok. Shellfish anaphylaxis was most common in children aged 7-17. Adrenaline was administered in 60% of cases, with 9% given adrenaline before hospital arrival. Adrenaline devices were prescribed in up to 82% of cases in Thailand but none in Qingdao. CONCLUSIONS: The APRA identified food as the main trigger of anaphylaxis in children, but causative allergens differed even across Asian countries. Fewer than two-thirds of cases received adrenaline treatment, pre-hospital adrenaline usage was low, and adrenaline device prescription remained suboptimal. The registry recognizes an unmet need to strengthen anaphylaxis care and research in Asia-Pacific.

Level of asthma control in children and adolescents before and during the COVID-19 pandemic.

BACKGROUND: During the COVID-19 pandemic, national lockdowns were implemented worldwide. Asthma control was reported to have improved. However, some patients lost follow-up from the clinic because they intended to avoid crowds at the hospital. OBJECTIVE: To evaluate the level of asthma control during the COVID-19 pandemic and explore factors influencing asthma outcomes. METHODS: Subjects 8-18 years old from our previous study in 2019 were recruited. The data during the pandemic period were collected between June 2021 - May 2023. The level of asthma control was compared before and during the pandemic. We also evaluated inhaled corticosteroid (ICS) adherence and factors related to poor asthma control during the COVID-19 pandemic. RESULTS: One hundred and three subjects were enrolled. Asthma control levels remained relatively stable during the pandemic. However, an asthma exacerbation was significantly decreased from 36 (36.3%) in 2019 to 19 (19.2%)and 15 (15.1%) in 2021 and 2022 (p = 0.012, p < 0.001), respectively. Spirometry results demonstrated improved pre-bronchodilator FEV1 (89.91 ± 11.02 vs. 101.91 ± 14.11, p < 0.001). The factors related to the poor asthma outcome were not wearing a face mask (aOR = 8.52, 95%CI 1.26-57.79) and previously poor-controlled by the ACT score (aOR = 2.55, 95%CI 1.41-4.63). The median adherence rate during the pandemic was 85%. The main reasons for poor adherence were hectic lifestyle and misunderstandings of disease. CONCLUSION: Asthma exacerbation was significantly decreased during the lockdown. Not wearing a face mask and previously poorly controlled by the ACT score are related to poor asthma outcomes.

Factor associated with food allergy among preschool children with atopic dermatitis, and resolution of atopic dermatitis.

BACKGROUND: Food allergy (FA) has been reported in one-third of children with moderate-to-severe atopic dermatitis (AD). OBJECTIVE: To identify factor associated with food allergy among preschool children with AD, and to compare AD resolution between preschool children with and without FA. METHODS: A cross-sectional study using database registry and questionnaire interview was conducted at Siriraj Hospital(Bangkok, Thailand) during 2022, and physician-diagnosed AD children aged ≤ 6 years were enrolled. RESULTS: A total of 110 children (60.9% male, median age: 2.3 years) were included. Of those, 53 and 57 children had AD with and without FA, respectively. Very early-onset AD (≤ 3 months) and moderate-to-severe AD at onset were reported in 43.9% and 26.3% of AD without FA, and in 35.8% and 45.3% of AD with FA, respectively. The most commonly reported FAs were hen's egg, cow's milk, and wheat. Moderate-to-severe AD at onset was found significant associated with FA (aOR: 2.50; p = 0.037). Thirty-one (28.2%) patients experienced completed resolution of AD by 5 years of age. Of those, 19 had AD without FA, and 12 had AD with FA (p = 0.213). The median age at AD resolution was 18 months and 22.5 months in the without and with FA groups, respectively. AD with FA showed a strong trend toward a significantly longer duration to achieving AD resolution after adjusting for onset and severity of AD (aHR: 0.46, p = 0.050). CONCLUSION: Preschool AD children with FA were found to have significantly greater AD severity at AD onset and a longer duration to AD resolution compared to AD children without FA.

Treatment Difficulties in Wheat Oral Immunotherapy and the Predictive Value of Wheat-Specific IgE.

BACKGROUND: Factors associated with wheat oral immunotherapy (OIT) difficulties in patients with IgE-mediated wheat allergy have not been well studied. OBJECTIVE: We aimed to assess factors associated with difficulties in wheat OIT. METHODS: We retrospectively collected data from children under 18 years of age with history of IgE-mediated wheat allergy who underwent wheat OIT. The initial specific IgE (sIgE) of wheat and omega-5-gliadin, wheat skin prick test (SPT) sizes, eliciting doses, and adverse reactions during the OIT were evaluated. RESULTS: A total of 81 children were enrolled, with a mean age of 7.0 ± 2.7 years at the initiation of wheat OIT. The median follow-up duration was 2 years (IQR 1.2 -3.0 years). Difficulties in wheat OIT included patients who experienced frequent reactions (at least grade 2 or exercise-induced reactions) or deviated from the up-dosing protocol, which we defined as 'Complicated cases.' Twenty-six patients (32.1%) were complicated cases. Initial wheat-sIgEs were significantly higher in complicated cases than in noncomplicated cases (median of 192.3 kUA/L (IQR 30.4-590.0) vs 6.9 kUA/L (IQR 1.9-100.0) (p = 0.001)). Initial omega-5-gliadin-sIgEs in the complicated group were also significantly higher, with a median of 15.0 kUA/L (IQR 6.3-69.8) vs 1.6 kUA/L (IQR 0.2-11.4) (p < 0.001). The risk factors for complicated cases include higher omega-5-gliadin-sIgEs and anaphylaxis during the oral food challenge test (aOR 1.035 and 5.684, respectively). CONCLUSION: The initial wheat and omega-5-gliadin-sIgEs were significant risk factors for complicated OIT patients and could be used to monitor these patients carefully during the OIT period.

Validation and Reliability of the Thai version of the Food Allergy Quality of Life Questionnaire-Parent Form (FAQLQ-PF).

BACKGROUND: Food allergy has an impact on the quality of life of both patients and caregivers. It is, therefore, important to have a native language survey to evaluate health-related quality of life (HRQL) among food allergic children. OBJECTIVE: To translate the Food Allergy Quality of Life Questionnaire-Parent Form (FAQLQ-PF) to Thai language, and to validate this tool in Thai parents with food allergic children. METHODS: The FAQLQ-PF was translated into Thai language according to WHO guideline. The FAQLQ-PF Thai version was then administered to the parents of food allergic Thai children aged 0-12 years. The FAQLQ-PF Thai version was then readministered to those same parents 10-14 days after they first completed this assessment tool. Internal consistency by Cronbach's α and test-retest reliability by intraclass correlation coefficient (ICC) were assessed. The discriminant validity of the questionnaire was also evaluated. RESULTS: Ninety parents of participants answered the FAQLQ-PF Thai version. Of those, 9 parents (10%) incompletely answered the first questionnaire. The FAQLQ-PF Thai version showed good internal consistency (Cronbach's α ≥ 0.799), but the test-retest reliability was only fair (ICC > 0.6). Factors that adversely affected the quality of life of Thai children with food allergy included age, presence of anaphylaxis, frequency of reactions, and the number of implicated foods. Patients with wheat allergy were negatively impacted in all domains of quality of life, whereas those with shellfish allergy had only emotional impact. CONCLUSIONS: The FAQLQ-PF Thai version is a reliable and valid tool for assessing HRQL in Thai children with food allergy.

Is mold sensitization associated with severe asthma exacerbation in children?

BACKGROUND: Mold sensitization has been reported as a factor associated with severe asthma exacerbation (SAE). OBJECTIVE: To identify the factors associated with SAE in asthmatic children, particularly mold sensitization. METHODS: The asthmatic children recruited into this case-control study were classified into an SAE and an outpatient (OPD) group, based on their histories of asthma exacerbation with hospitalization in the preceding year. A skin prick test to common aeroallergens was performed. Possible SAE risk factors were analyzed. RESULTS: A total of 102 patients were enrolled. The 51 patients in the SAE group were significantly younger than the 51 in the OPD group (mean ages of 6.8 ± 3.3 vs 8.7 ±3.2 years, p = 0.005). Higher proportions of patients with partly controlled or uncontrolled asthma were found in the SAE group (41.2% vs 17.6%, p = 0.009). The incidences of a paternal history of atopy, an emergency department visit, and a history of systemic corticosteroid administration in the preceding year were significantly higher for the SAE group (35.3% vs 15.7%, p = 0.023; 100% vs 43.5%, p < 0.001; and 100% vs 31.4%, p < 0.001; respectively). The multivariate logistic regression analysis showed that risk factors for SAE were Alternaria sensitization (adjusted odds ratio [AOR] 3.00; 95% CI 1.09-8.3; p = 0.033), patients who were younger than 6 years (AOR 3.28; 95% CI 1.17-9.18; p = 0.024), and a paternal history of atopy (AOR 2.94; 95% CI 1.05-8.25; p = 0.040). CONCLUSIONS: Alternaria sensitization, an age younger than 6 years, and a paternal history of atopy were associated with SAE in asthmatic children.

The natural history of childhood-onset nonallergic rhinitis; a long-term follow-up study.

BACKGROUND: Non-allergic rhinitis (NAR) is characterized by symptoms of nasal inflammation without allergic sensitization. The long-term outcome of NAR in children is poorly defined. OBJECTIVE: To determine the natural history of childhood-onset NAR and the development of allergic rhinitis (AR) in these children. METHODS: NAR patients who were followed for more than 10 years were evaluated at 3-5 years (E2) and 9-12 years (E3) after the first evaluation (E1). Nasal symptoms, disease severity, comorbidities, medication used, and aeroallergen sensitization were assessed. RESULTS: Eighty-two NAR patients (58.5% male) completed all 3 evaluations. The age at onset was 2.0 (range 2.0-4.0) years. The follow-up period was 13.6 (range 12.3-14.3) years. At E2, 37.8% of patients developed AR. At E3, the patients were classified into four groups based on results of skin prick tests in E2 and E3 (group I: NAR→NAR→NAR, 39.0%, group II: NAR→NAR→AR, 23.2%, group III: NAR→AR→NAR, 12.2% and group IV: NAR→AR→AR, 25.6%). The most common aeroallergen sensitization was house dust mite. The family history of atopy, asthma and allergic rhinitis were higher in group III and IV than other groups (p < 0.05). The atopic dermatitis, obstructive sleep apnea and adenotonsillar hypertrophy at E1 and E2 were predominantly found in group IV (p < 0.05). At E2, group III and IV patients had higher proportion of exposure to house dust, animal dander and smoking compared to other groups (p < 0.05). The overall remission rate was 14.6%. CONCLUSIONS: Children with NAR should be reevaluated periodically to determine aeroallergen sensitization for the appropriate diagnosis and management.

A potential role of gliadin extract skin prick test in IgE-mediated wheat allergy.

BACKGROUND: Wheat extracts containing both water/salt and alcohol soluble proteins may increase extract's accuracy for diagnosing IgE-mediated wheat allergy. OBJECTIVE: This study aimed to determine the performance of new invented in-house prepared wheat extracts for skin prick test (SPT). METHODS: Children aged 1-18 years with history of immediate wheat allergy were recruited. Four in-house prepared wheat extracts (wheat-Coca-10%EtOH, and 3 new invented extracts, wheat-salt, gliadin, and glutenin) and a commercial wheat extract were used for SPT. Serum specific IgE (sIgE) to wheat and omega-5 (ω-5) gliadin were also determined. Oral food challenge (OFC) with wheat flours was performed in all patients except those with history of wheat-induced anaphylaxis or with recent symptoms within the past 6 months. RESULTS: Thirty-one children were recruited. Of those, 14 were excluded from OFC (12 with history of anaphylaxis and 2 with recent symptom). OFC was positive in 8 of 17 children. Of the 5 extracts and sIgE to wheat and ω-5 gliadin, gliadin extract provided the best SPT performance with 84.2% sensitivity, 88.9% specificity, 94.1% positive predictive value (PPV), 72.7% negative predictive value (NPV), 7.59 positive likelihood ratio (LR), 0.18 negative LR, and 85.7% accuracy. CONCLUSIONS: Compared to other in-house and commercial wheat extracts and sIgE to wheat and ω-5 gliadin, SPT with an in-house gliadin extract yielded the highest performance for the diagnosis IgE-mediated wheat allergy.

Effects of a new amino acid, rice glucose polymer-based, and commercial amino acid-based formulas on growth and protein status of infants with cow's milk protein allergy.

BACKGROUND: Infants with cow's milk protein allergy (CMPA) are at risk for nutrient inadequacy and impaired growth. OBJECTIVE: To evaluate the effect of a new amino acid-based formula (nAAF) compared with commercial amino acid-based formula (cAAF) on growth and protein status of cow's milk protein (CMP)-allergic infants and to compare their growth with those of healthy infants. METHODS: Infants less than 6 months of age with CMPA were enrolled in the nAAF or cAAF groups. Healthy infants fed breast milk (BM) or infant formula (IF) were controls. They remained on their formula/milk until day 28 of the study. Anthropometric evaluation was performed at birth, day 0 and day 28 of the study and calculated to z-scores of weight-for-age (WAZ), length-for-age (LAZ) and head circumference-for-age (HAZ). Plasma amino acids, albumin, urea nitrogen, and creatinine were assessed for infants with CMPA on day 0 and day 28. RESULTS: The nAAF and cAAF groups did not differ in increases in WAZ [regression coefficient (95%CI): 0.088 (-0.619, 0.796), p = 0.791], LAZ [0.045 (-0.789, 0.880, p = 0.909], and HAZ [-0.645 (-2.082, 0.793), p = 0.337] between day 0 and day 28. The increases in WAZ and LAZ during 28 days in the nAAF group did not differ from the controls. The changes in the blood chemistry values, except albumin, were not different between CMPA groups. CONCLUSIONS: The nAAF, similar to the cAAF, supports growth and protein status for infants with CMPA, and it might be used as a substitute for the cAAF.

Identifying the stability of a new wheat gliadin extract by protein analysis, skin tests and cell degranulation assay.

BACKGROUND: The commercial wheat extract for skin prick test (SPT) provides less sensitivity to predict wheat allergy, compared to in-house gliadin extracts. SPT is a preferred method to study extract stability as it is the aim of developing extract. The role of cell degranulation assay, a functional assay with the same mechanism as SPT, is not widely used to determine extract stability. OBJECTIVE: To study the stability of in-house gliadin extracts stored at different periods, by using protein analysis, SPT and degranulation assay of humanized rat basophilic-leukemia (RBL-SX38) cells. METHODS: Patients with a history of wheat allergy and positive SPT to wheat, were recruited. The gliadin extracts stored for 1, 6, 9, and 12 months at 2-8°C were used in SDS-PAGE, SPT and cell degranulation assay. The cell degranulation was determined by ß-hexosaminidase release. AR patients. RESULTS: Forty children were recruited. The gliadin extract stored for 9 and 12 months provided lighter protein bands than 1 and 6 months. However, the wheal diameters from SPT using extracts stored at different periods, were not significantly different (p = 0.09). There were also no significant differences of the ß-hexosaminidase released using 0.1 and 1 µg/mL of gliadin extracts stored at different periods (p > 0.05). The 10 µg/mL of gliadin extracts stored at longer periods, significantly stimulated higher ß-hexosaminidase release (p = 0.01). The extracts were sterile at all storage times. CONCLUSIONS: To determine the stability of in-house gliadin extracts, SPT or cell degranulation assay provided additional information to SDS-PAGE. The extracts were stable for up to 12 months.

Children with wheat anaphylaxis and with low wheat specific IgE have a different IgE immunoblot pattern than those with high wheat specific IgE.

BACKGROUND: Children with wheat anaphylaxis can present with a wide range of wheat-specific IgE (sIgE). OBJECTIVE: To identify differences in clinical features and predominant wheat allergens sensitized by these patients. METHODS: Children with history of wheat anaphylaxis were recruited. Skin prick test (SPT) to wheat, sIgE to wheat, omega-5 gliadin (ω5G), lipid transfer protein (LTP) were investigated. Profiles of IgE-bound wheat allergens were studied to identify predominant wheat allergens. RESULTS: Twenty-nine children (17 males) aged 1-18 years were enrolled. Sixteen patients (55.2%) had wheat-sIgE > 100 kUA/L (WAhi) and 13 patients (44.8%) had wheat-sIgE < 34 kUA/L (WAlo). The median of peak wheat-sIgE in WAhi and WAlo were 340.5 kUA/L (IQR 184.3, 564.5) and 12.2 kUA/L (IQR 1.4, 41.3), respectively. Oral food challenge test (OFC) was carried out in 12 of 13 patients in the WAlo group, all of which had positive results. Eight of these 12 patients developed anaphylaxis during OFC despite having wheat-sIgE less than 10 kUA/L. There were no differences in clinical characteristics and atopic history between WAhi vs. WAlo. Medium to low molecular weight gliadin (< 40 kDa) and glutenin (< 60 kDa) were commonly recognized by patients with WAhi. IgE immunoblot pattern among the WAlo group was more widely dispersed than those with WAhi. CONCLUSIONS: Wheat anaphylaxis can occur in patients with low wheat-sIgE. Predominant wheat allergens recognized by patients with WAlo were different than those with WAhi. Such difference could be responsible for anaphylaxis at even low levels of wheat-sIgE.

Comprehending the allergen repertoire of shrimp for precision molecular diagnosis of shrimp allergy.

BACKGROUND: Clinical management of shrimp allergy is hampered by the lack of accurate tests. Molecular diagnosis has been shown to more accurately reflect the clinical reactivity but the full spectrum of shrimp allergens and their clinical relevance are yet to be established. We therefore sought to comprehend the allergen repertoire of shrimp, investigate and compare the sensitization pattern and diagnostic value of the allergens in allergic subjects of two distinct populations. METHODS: Sera were collected from 85 subjects with challenge-proven or doctor-diagnosed shrimp allergy in Hong Kong and Thailand. The IgE-binding proteins of Penaeus monodon were probed by Western blotting and identified by mass spectrometry. Recombinant shrimp allergens were synthesized and analyzed for IgE sensitization by ELISA. RESULTS: Ten IgE-binding proteins were identified, and a comprehensive panel of 11 recombinant shrimp allergens was generated. The major shrimp allergens among Hong Kong subjects were troponin C (Pen m 6) and glycogen phosphorylase (Pen m 14, 47.1%), tropomyosin (Pen m 1, 41.2%) and sarcoplasmic-calcium binding protein (Pen m 4, 35.3%), while those among Thai subjects were Pen m 1 (68.8%), Pen m 6 (50.0%) and fatty acid-binding protein (Pen m 13, 37.5%). Component-based tests yielded significantly higher area under curve values (0.77-0.96) than shrimp extract-IgE test (0.70-0.75). Yet the best component test differed between populations; Pen m 1-IgE test added diagnostic value only in the Thai cohort, whereas sensitizations to other components were better predictors of shrimp allergy in Hong Kong patients. CONCLUSION: Pen m 14 was identified as a novel shrimp allergen predictive of challenge outcome. Molecular diagnosis better predicts shrimp allergy than conventional tests, but the relevant component is population dependent.

Clinical characteristics and outcomes of ocular allergy in Thai children.

BACKGROUND: Allergic conjunctivitis (AC) is the most common ocular condition in allergic children. In tropical countries, the study about the clinical features and outcome of treatment is very limited. OBJECTIVE: To review clinical characteristics and outcomes of treatment in children with ocular allergy. METHODS: Children with history of AC were classified to seasonal allergic conjunctivitis (SAC), perennial allergic conjunctivitis (PAC), vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC). The clinical history and outcome of treatment were recorded. RESULTS: One hundred and sixty-four children were recruited. PAC was the most common type (61.6%), followed by SAC (21.3%), VKC (12.2%), and AKC (4.9%). Male preponderance was found in all groups. Mean age of onset was 6.8 ± 2.8 years. Allergic rhinitis was the most common co-morbidity (97.6%). The common sensitized allergen is house-dust mites (86.1%). Standard treatments in all groups were natural tear and topical olopatadine. Add-on medications were usually needed in severe types of AC (VKC, AKC). History of topical corticosteroid use was 68.8% and 12.5% in VKC and AKC, respectively. All of them can discontinue topical corticosteroid when topical tacrolimus was applied. The overall remission was found 35% in VKC group and 63% in AKC group. The median duration of treatment was 20.5 months in VKC group and 11 months in AKC group. CONCLUSIONS: most Thai children with AC sensitized to house-dust mites. In severe forms of AC, most patients needed addon medication. The use of topical calcineurin inhibitor as an add-on therapy can decrease the use of topical corticosteroid.

Characterization of children with IgE-mediated wheat allergy and risk factors that predict wheat anaphylaxis.

BACKGROUND: The number of children presenting with IgE-mediated wheat reactions to academic medical centers in Thailand continues to increase. OBJECTIVE: Improved knowledge about the clinical characteristic of wheat allergy is urgently needed to better understand the risk factors and to improve proper treatment in this patient population. METHODS: A cross-sectional study using questionnaire review of children who presented with IgE-mediated wheat allergy during 2001 to 2015 was performed. Patients were divided into the wheat anaphylaxis (WA) or the only skin symptoms (SO) group. RESULTS: One hundred children were enrolled. Fifty-one and 49 patients were allocated to the WA and SO group, respectively. The median age was 40.5 months (range: 6-200), and the median age of onset was 7 months (range: 3-96). The vast majrity (90%) developed their first reaction after their first ingestion of wheat. Atopic dermatitis (AD) was found to be the only significant difference between groups and found more commonly in SO than in WA (59.2% vs. 35.3%, p = 0.02). Median mean wheal diameter (MWD) of skin prick test (SPT) and median sIgE level to wheat were higher in WA than in SO (8 vs. 3 mm, p < 0.001; and, 33.3 vs. 3.6 kUA/l, p < 0.001). CONCLUSIONS: Children with wheat allergy presented very early in life. AD was found in approximately half of the patients, and more commonly in SO. Median MWD of SPT and sIgE level to wheat were significantly higher in WA. These data will aid in further planning for a larger survey and intervention study in wheat allergy.

Prevalence of rat and mouse sensitization in Asian patients with respiratory allergy.

BACKGROUND: Skin prick test (SPT) is useful in identifying rat and mouse sensitization. OBJECTIVE: To determine the prevalence of rat and mouse sensitization by using local and commercial allergen extracts. METHODS: Patients with allergic rhinitis or asthma were recruited. SPT of local and commercial rat and mouse allergen extracts were performed. The level of rat and mouse specific IgE (sIgE) was quantified in all patients with positive SPT and randomized patients with negative SPT. RESULTS: Two hundred and thirty patients, 108 male (47%) and median age 14 years (3.2-63.5 years), were enrolled. Rat sensitization by SPT was 11.7% and mouse sensitization was 17.8%. SPT result to local rat and commercial rat allergen extracts were moderately correlated (rs = 0.51, p < 0.001), while SPT result to local mouse and commercial mouse allergen extracts showed low correlation (rs = 0.38, p < 0.001). The concordance of SPT results between local rat and commercial rat allergen extracts was 90.4%. Concordance between the local mouse and commercial mouse allergen extracts was 85.2%. When compared with rat and mouse sIgE, the concordance of local rat, commercial rat and commercial mouse allergen extract were > 80% while that of local mouse was 54.4%. No adverse effect was observed in SPT with any allergen or extract. CONCLUSIONS: The prevalence of rat and mouse sensitization was low compared to the study in USA. SPT with local rat and mouse allergen extract was safe and showed good concordance with the SPT result of commercial allergen extracts and rat and mouse sIgE levels.

The role of the environment in shaping the trends of childhood asthma - An Asian perspective.

Asthma has now become one of the most common atopic disorders not only in developed countries but also in many developing countries. The etiology is likely due to a complex interaction between genetic and environmental factors. In many Asian countries, the prevalence of asthma has also been documented by validated instruments to be increasing rapidly over the past two decades. However, studies in rural areas in Asia with a traditional farming environment revealed markedly lower asthma prevalence when compared with residents in nearby cities despite having similar genetic background. Among the environmental factors implicated in the pathogenesis of asthma, air pollution, dietary patterns, viral infections, and early microbial exposure have been studied extensively around the world. Asia provides many opportunities to study these potential factors as there are many ethnic groups living in distinctly different environments. The understanding of the roles of these factors in affecting the early immune system and subsequent development of asthma will enable us to develop potential primary preventive strategies against a disease which affects millions worldwide.

Exercise-food challenge test in patients with wheat-dependent exercise-induced anaphylaxis.

BACKGROUND: Wheat-dependent exercise-induced anaphylaxis (WDEIA) is a severe and potentially life-threatening food allergy. Diagnosis of WDEIA is challenging because reactions are not always reproducible. OBJECTIVE: This study aimed to evaluate the positivity rate of exercise-food challenge test at our allergy unit in order to confirm the diagnosis, and to investigate the effect on the episode of reactions after the test. METHODS: This retrospective evaluation included patients aged 5-60 years who presented at the pediatric and adult allergy units of Siriraj Hospital during 2014-2018 with a convincing history of WDEIA and who underwent a 4-day exercise-food challenge test. Demographic data, challenge test result, and episodes of the reaction before and after the challenge test were obtained. RESULTS: Fourteen of the 17 patients that were enrolled were included in the analysis. The 3 excluded patients were found to have IgE-mediated wheat allergy. Median age and time to diagnosis was 18.3 years (range: 10.5-43.4) and 1.8 years (range: 0.3-6.2). History of recurrent acute urticaria before the onset of anaphylaxis was reported in 5 patients (35.7%). Exercise-food challenge test was positive in 10 patients (71.4%). Median mean number of exacerbations per year before and after the confirmation test was 2 (range: 1-10) and 1 (range: 0-3), respectively. CONCLUSIONS: For WDEIA, time to diagnosis was delayed, and one-third of patients had recurrent acute urticaria proceeding anaphylaxis onset. Our exercise-food challenge test could be utilized safely in both children and adult and able to elicit symptoms in two-third of patients.

Disseminated cryptococcosis in two boys with novel mutation of CD40 Ligand-Associated X-linked hyper-IgM syndrome.

X-linked hyper-IgM syndrome (XHIM) caused by CD40L mutations is a primary immunodeficiency condition that increases susceptibility to opportunistic infections. Disseminated cryptococcosis in XHIM is rarely reported in children. Here, we report two related boys who have a novel hemizygous frameshift c.208delC mutation of CD40L. They live in the western region of Thailand and developed disseminated cryptococcosis while receiving regular intravenous immunoglobulin supplementation.

Natural resolution of non-anaphylactic shrimp allergy in patients diagnosed 10 years earlier by oral food challenge.

BACKGROUND: Shrimp allergy is considered a lifelong condition. The natural resolution of shrimp allergy is not well studied. OBJECTIVE: To investigate the natural resolution of shrimp allergy among a cohort of patients diagnosed with shrimp allergy 10 years earlier by oral shrimp challenge. METHODS: A prospective study recruited patients diagnosed with shrimp allergy to Penaeus monodon (Pm), Macrobrachium rosenbergii (Mr), or both from a study conducted during 2005-2006. The current oral shrimp challenges were conducted during 2015-2016. The negative oral shrimp challenge was designated 'resolved shrimp allergy' (RSA), with a positive challenge designated 'persistent shrimp allergy' (PSA). Skin prick and prick-to-prick testing to shrimp were used to determine sensitization. RESULTS: Sixty patients who had positive shrimp challenge from the previous cohort were contacted. Patients who had previous anaphylactic reaction (8 subjects) or allergic reaction after shrimp ingestion within 6 months (6 subjects), were not included. Nine patients refused to participate and 20 patients could not be contacted. Seventeen patients were included. Three were previously diagnosed with allergy to Pm, 3 to Mr, and 11 to both species. RSA was observed in 1 patient with isolated Pm allergy, and in 3 patients with isolated Mr allergy. Three of 9 patients with dual allergy had RSA to both species. RSA patients had significantly smaller size of shrimp skin test than PSA patients at both diagnosis and follow-up. CONCLUSIONS: At ten years after diagnosis, 46% of patients had RSA. These patients had significantly smaller size of shrimp skin test than PSA patients.

Prick and intradermal skin tests in patients with severe hymenoptera sting allergy using commercial versus in-house allergen extracts.

BACKGROUND: Fire ant, honey bee, and wasp allergen extracts are useful in the diagnosis and treatment of severe Hymenoptera allergic patients. OBJECTIVE: To evaluate the result of skin prick test (SPT) and intradermal test (ID) compared between local and commercial insect allergen extracts in patients with severe Hymenoptera sting allergy. METHODS: SPT and ID using local and commercial insect allergen extracts were performed. Specific IgE (sIgE) to honey bee, wasp, and fire ant; component-resolved diagnosis (CRD); (rApi m1, rApi m2, rApi m3, rApi m5, rApi m10, rVes v5, rPol d5, and rVes v1); and, cross-reactive carbohydrate determinant (CCD) were performed. RESULTS: Twenty-seven patients were included. Twenty-five had anaphylaxis, and 2 had severe systemic skin reaction. Positive skin test (SPT and/or ID) result from local and commercial allergen extracts was 74% vs. 67% for fire ant, 48% vs. 59% for honey bee, and 52% vs. 74% for yellowjacket. Local and commercial allergen extracts showed substantial agreement for fire ant (k = 0.647, p = 0.001) and honey bee (k = 0.632, p = 0.001), and moderate agreement for wasp (k = 0.547, p = 0.001). When compared with sIgE subtracted with CCD and/or CRD, skin test results of local fire ant allergen extract showed higher sensitivity (87% vs. 67%), specificity (42% vs. 33%), and accuracy (67% vs. 52%) than commercial extract. Commercial honey bee and wasp showed higher sensitivity (62% vs. 50%, 85% vs. 65%) and accuracy (63% vs. 52%, 78% vs. 70%), respectively. CONCLUSIONS: SPT and ID with local or commercial insect venoms could help in confirming and/or identifying the causative insects.