Diagnostic Decision Points of Specific IgE Concentrations in Korean Children With Egg and Cow's Milk Allergies

Systematic review and meta-analyses on the accuracy of diagnostic tests for IgE-mediated food allergy

The European Academy of Allergy and Clinical Immunology (EAACI) is updating the Guidelines on Food Allergy Diagnosis. We aimed to undertake a systematic review of the literature with meta-analyses to assess the accuracy of diagnostic tests for IgE-mediated food allergy. We searched three databases (Cochrane CENTRAL (Trials), MEDLINE (OVID) and Embase (OVID)) for diagnostic test accuracy studies published between 1 October 2012 and 30 June 2021 according to a previously published protocol (CRD42021259186). We independently screened abstracts, extracted data from full texts and assessed risk of bias with QUADRAS 2 tool in duplicate. Meta-analyses were undertaken for food-test combinations for which three or more studies were available. A total of 149 studies comprising 24,489 patients met the inclusion criteria and they were generally heterogeneous. 60.4% of studies were in children ≤12 years of age, 54.3% were undertaken in Europe, ≥95% were conducted in a specialized paediatric or allergy clinical setting and all included oral food challenge in at least a percentage of enrolled patients, in 21.5% double-blind placebo-controlled food challenges. Skin prick test (SPT) with fresh cow's milk and raw egg had high sensitivity (90% and 94%) for milk and cooked egg allergies. Specific IgE (sIgE) to individual components had high specificity: Ara h 2-sIgE had 92%, Cor a 14-sIgE 95%, Ana o 3-sIgE 94%, casein-sIgE 93%, ovomucoid-sIgE 92/91% for the diagnosis of peanut, hazelnut, cashew, cow's milk and raw/cooked egg allergies, respectively. The basophil activation test (BAT) was highly specific for the diagnosis of peanut (90%) and sesame (93%) allergies. In conclusion, SPT and specific IgE to extracts had high sensitivity whereas specific IgE to components and BAT had high specificity to support the diagnosis of individual food allergies.

Infantile Anaphylaxis in Korea: a Multicenter Retrospective Case Study

BACKGROUND

Anaphylaxis is increasing in young children. The aim of the present study was to analyze the clinical characteristics of anaphylaxis in Korean infants, with a focus on food triggers.

METHODS

The study analyzed the medical records of infants aged 0 to 2 years old who had been diagnosed with anaphylaxis in 23 secondary or tertiary hospitals in Korea.

RESULTS

We identified 363 cases of infantile anaphylaxis (66.9% male). Cutaneous symptoms were most prevalent (98.6%), followed by respiratory (83.2%), gastrointestinal (29.8%), and neurologic (11.6%) symptoms. Cardiovascular symptoms were noted in 7.7% of the cases. Most of the cases of anaphylaxis (338; 93.1%) were induced by foods. The most common trigger food was cow's milk and cow's milk products (43.8%), followed by hen's eggs (21.9%), walnuts (8.3%), wheat (7.7%), peanuts (4.8%), other nuts (3.0%), and fish (2.1%). In cow's milk-induced anaphylaxis cases, more than half the cases had cow's milk specific immunoglobulin E (sIgE) levels that were lower than the diagnostic decision points (DDPs), which is 5 kUA/L for those under the age of 1 and 15 kUA/L for those over the age of 1. In anaphylaxis induced by hen's egg, most of the cases (91.8%) had hen's egg sIgE levels that were higher than the DDP, which is 2 kUA/L for those under the age of 2 and 7 kUA/L for those over the age of 2. Of the infantile anaphylaxis cases, 46.8% had been treated with epinephrine, and 25.1% had been prescribed an epinephrine auto-injector.

CONCLUSION

Cow's milk is the most frequent trigger food of anaphylaxis in Korean infants. However, we found no significant correlation between the sIgE level and clinical severity. Education is required regarding the importance of epinephrine as the first line therapy for anaphylaxis and on properly prescribing epinephrine for infants with a history of anaphylaxis.

Prevalence of food-allergen and aeroallergen sensitization among people in Sichuan, Western China: An 8-year observational study

BACKGROUND

Identifying the distribution of allergens is invaluable to effective diagnosis and treatment of allergic disease. The present study aims to analyze the epidemiology of allergens in Sichuan, Western China.

METHODS

A total of 14 030 participants including 8031 men and 5999 women were enrolled in this study during 2007-2014 in West China Hospital. An assay testing for the presence of allergen-specific IgE was used to identify highly immunogenic allergens.

RESULTS

Of the 14 030 total participants, 3470 (24.72%) were sensitive to at least one of tested allergens. The most immunogenic allergens were mite mix (1876, 13.38%), crab (876, 6.24%), sea-fish mix (865, 6.16%), house dust (355, 2.54%), and cockroach (292, 2.08%). The differences between population of participants who were sensitive to food allergens and aeroallergens were statistically significant in 0 to 10, 11 to 20, 21 to 30, 41 to 50, and 51 to 60 year-old age-groups (all P < 0.05). Distributions of three food allergens and two aeroallergens were significantly different between male and female participants. There was also an increase in sensitization to cow's milk, mutton, sea-fish, and mould that was observed in the 71 to 90 year-old group.

CONCLUSION

The most common allergens presented in Sichuan were observed to be mites, crab, sea-fish, and house dust. There was an observable difference in sensitivity to five allergens between males and females. Additionally, aeroallergens appeared to have a greater immunogenic effect in younger populations while the elderly presented with increased sensitization to specific allergens, suggesting that specific allergens' immunogenicity was age-dependent.

Accuracy of serum IgE concentrations and papule diameter in the diagnosis of cow's milk allergy

OBJECTIVE

To compare serum concentrations of specific IgE and mean papule diameters induced in the immediate skin reactivity test with cow's milk and its fractions with results of the oral challenge test, and to establish cutoff points capable of predicting clinical reactivity to cow's milk in patients treated at a referral service.

METHODS

One hundred and twenty-two children (median of 17 months) with a history of immediate reactions to cow's milk and presence of specific IgE for cow's milk and/or its fractions (positive skin and/or IgE serum tests) were submitted to open oral challenge test with cow's milk.

RESULTS

The oral challenge test was positive in 59.8% of the children, 49% of whom were males. Serum levels of specific IgE, as well as mean cow's milk papule diameters, were significantly higher in allergic patients (medians: 3.39kUA/L vs. 1.16kUA/L, 2.5mm vs. 0mm). The optimal cutoff points (Youden's index) of serum IgE specific for cow's milk and its fractions capable of predicting cow's milk reactivity (positive oral challenge test) were: 5.17kUA/L for cow's milk, 0.95kUA/L for α-lactalbumin, 0.82kUA/L for β-lactoglobulin, and 0.72kUA/L for casein, whereas for papule diameters the cutoff points were 3.5mm for cow's milk and 6.5mm, 9.0mm, and 3.0mm for the α-lactalbumin, β-lactoglobulin, and casein fractions, respectively.

CONCLUSIONS

The cutoff points capable of predicting clinical reactivity to cow's milk were: 5.17kUA/L for serum-specific IgE and 3.5mm for papule diameter measurement, values considered discriminatory for the diagnosis of cow's milk allergy.

Oral food challenges: result of a 16-year experience at a major teaching hospital in Thailand

Background

Prevalence of food allergy is increasing all over the world including in Asia. Diagnosis of food allergy in Asia is usually made after family complaints or by elimination and/or reintroduction foods. This could lead to an inaccurate diagnosis and to incorrect information on epidemiology of food allergy. We, herein, reported results of a 16-year experience (1996–2012) of oral food challenge (OFC) performed in pediatric patients at a major teaching hospital in Thailand.

Objective

The major objectives of this report are to review types of foods selected for oral challenges, frequency of positive/negative challenges to these foods and the clinical reactions during challenges among these children.

Methods

Medical records of 206 children underwent OFC between 1996 and 2012 for various indications at the Allergy clinic of Pediatric Department, Siriraj Hospital, Mahidol University (age range, 4 months to 17 years) were retrospectively reviewed. Data including clinical data, skin prick test results and specific IgE levels were analyzed with respect to challenge results (positive/negative). During the period of the study, 2 separate investigations on shrimp allergy and wheat allergy were conducted.

Results

Sixty of 206 children (29%) had positive OFC, whereas 84 out of 306 OFC (27.5%) were positive. The most common food giving positive challenges in this study was shrimp (40%). Among children less than 3 years of age, the most common food with positive challenge was wheat (70%) whereas among children 3 years of age or older, shellfish was the most common food (42%). Cutaneous reactions were the most common reactions observed.

Conclusion

Only 1 out of 3 children underwent OFC in this study had positive challenges. Shrimp was the most common food causing challenge in this study especially among children older than 3 years of age. Wheat has become another leading food besides cow's milk and egg in causing positive OFC in younger children in Thailand.

Diagnostic values for egg white specific IgE levels with the skin prick test in Turkish children with egg white allergy

BACKGROUND

The diagnostic values for the skin prick test (SPT) diameters and egg white-specific IgE (EW-sIgE) levels that will allow us to predict the result of the oral food challenge test (OFC) in the diagnosis of egg white allergy vary by the community where the study is carried out.

OBJECTIVE

This study aimed to determine the diagnostic values of SPT and EW-sIgE levels in the diagnosis of egg white allergy.

METHODS

59 patients followed with the diagnosis of egg allergy September 2013 to September 2015 were included in our retrospective cross-sectional study. The patients were investigated in terms of egg and anaphylaxis history or the requirement of the OFC positivity. The demographic, clinical and laboratory findings of the cases were recorded, and they were compared with the patients with the suspected egg allergy but negative OFC (n=47).

RESULTS

In the study, for all age groups, the value of 5mm in SPT was found to be significant at 96.4% positive predictive value (PPV) and 97.8% specificity and the value of 5.27kU/L for EW-sIgE was found to be significant at 76% PPV and 86.6% specificity for egg white. The diagnostic power of the SPT for egg white (AUC: 72.2%) was determined to be significantly higher compared to the diagnostic power of the EW-sIgE (AUC: 52.3%) (p<0.05).

CONCLUSION

Along with the determination of the diagnostic values of communities, the rapid and accurate diagnosis of the children with a food allergy will be ensured, and the patient follow-up will be made easier.

IgE-mediated food allergies in children: prevalence, triggers, and management

Food allergy (FA) is a serious health problem, and severe FA such as food-induced anaphylaxis can often be life threatening. The incidence of FA has been increasing especially in children. They usually develop early in life and affect up to 10% of children. The 2 most common food allergens worldwide are milk and eggs, while the third one varies depending on the countries: peanuts in the United States and Switzerland, wheat in Germany and Japan, tree nuts in Spain, sesame in Israel, and walnuts in Korea. These common food allergens are different and difficult to identify because of differing study methodologies, population, geography, age, and dietary exposure patterns. The current management of FA relies on the strict avoidance of culprit allergens, the prompt treatment of allergic reactions, including epinephrine use for food-induced anaphylaxis, monitoring, and education to prevent further reactions. Newer approaches for tolerance induction to FA and FA immunotherapy have been under investigation but are not yet ready for real-world application. Thus, consistent and systematic education of patients, caregivers, and food-handling people is of primary importance for the management and prevention of FA reactions. This review assesses and compares IgE-mediated FA in children in Korea and other countries, with a focus on summarizing the prevalence, common triggers, and management of FA.

Predictive values of egg-specific IgE by two commonly used assay systems for the diagnosis of egg allergy in young children: a prospective multicenter study

Background

Specific IgE (sIgE) is often used to predict oral food challenge (OFC) outcomes in food allergy, but interpretation of the results may vary depending on the assay method employed and the patient population tested. The aim of this study was to use two commercial assay systems to determine egg‐sIgE values predictive of allergy within the most common populations treated at pediatric clinics.

Methods

In a multicenter prospective study, 433 children with suspected or confirmed egg allergy underwent oral challenge (OFC) using cooked egg (CE) and raw egg (RE) powders to diagnose either true allergy in 1‐year‐old (group A, n = 220) or tolerance in 2‐ to 6‐year‐old (group B, n = 213). Egg white (EW)‐ and ovomucoid (OM)‐sIgE values were measured using the ImmunoCAP^®sIgE (ImmunoCAP) and the IMMULITE^® 2000 3 gAllergy^™ (3gAllergy) systems. Children were recruited from six primary care clinics and 18 hospitals in Japan.

Results

Receiver‐operating characteristic (ROC) curve analysis yielded similar areas under the curve (AUC) for the two assays (0.7–0.8). The optimal cutoff values and the probability curves (PCs) of the sIgE by the two assays to predict CE and RE OFC outcomes were determined for both groups. Values for 3gAllergy were higher than for ImmunoCAP; however, correlation of sIgE and predicted probability calculated by PCs were strong between the two methods.

Conclusions

Cutoff values and PCs for egg‐sIgE established using both ImmunoCAP and 3gAllergy may be useful for predicting egg allergy in early childhood patient populations.

Food Allergy in childhood: phenotypes, prevention and treatment

The prevalence of food allergy in childhood increased in the last decades, especially in Westernized countries where this phenomenon has been indicated as a second wave of the allergic epidemic. In parallel, scientific interest also increased with the effort to explain the reasons of this sudden rise and to identify potential protective and risk factors. A great attention has been focused on early exposures to allergenic foods, as well as on other nutritional factors or supplements that may influence the immune system in a positive direction. Both interventions on maternal diet before birth or during breastfeeding and then directly on infant nutrition have been investigated. Furthermore, the natural history of food allergy also seems to be changing over time; IgE-mediated cow's milk allergy and egg allergy seem to be more frequently a persistent rather than a transient disease in childhood, as described in the last years. Food avoidance and the emergency drugs in case of an adverse event, such as epinephrine self-injector, are currently the first-line treatment in patients with food allergies, with a resulting impairment in the quality of life and social behaviour. During the last decade, oral immunotherapy emerged as an optional treatment with remarkable results, offering a novel perspective in the treatment for and management of food allergy.

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.