Food allergy has emerged as an important public health problem affecting people of all ages in many countries. The prevalence varies according to age, geographic regions, and ethnicity. For several years, many studies have suggested that the prevalence of food allergy is increasing at an alarming rate, for unclear reasons. Conversely, some studies have also provided findings that sensitization to common food allergens did not increase. Increased recognition rather than an actual increase in patients with IgE-mediated food allergy might lead to the increases in the prevalence of self-reported or physician-diagnosed food allergy. It is also noted that the prevalence of food allergy differs even in the same region according to the study design, i.e., hospital-based or community-based studies. Despite these limitations, epidemiologic data are important because they provide useful information on diagnosis, treatment, and prevention of food allergy. This review focuses on advances in the epidemiology of food allergy in Korean children.
Allergens ; Child ; Diagnosis ; Epidemiology ; Food Hypersensitivity ; Humans ; Prevalence ; Public Health

Atopic dermatitis (AD) is a chronic, relapsing, inflammatory skin disease. Children with AD tend to have a higher prevalence of food allergies. This study investigated the clinical significance of food sensitization in AD patients. A total of 266 AD patients participated in this study. The prevalence of food sensitization and clinically relevant sensitization were compared in the subjects according to their age and AD severity. Sera from all patients were analyzed for food-specific IgE levels using the Pharmacia CAP System FEIA. The serum specific IgE levels for egg, milk, peanut and soybean were measured. Patients were regarded as sensitized to the food if their food-specific IgE levels were above 0.35 kUA/L. Also the food-specific IgE levels, the so-called diagnostic decision point, which is recommended as the clinically relevant level, for clinical food allergy, as suggested by Sampson et al, was used as an alternative method. From the measurement of food-specific IgE antibodies of the four foods, egg was the most highly sensitized and the main causative allergenic food in children with AD. The positive rates of specific IgE to the four major food allergens, and the prevalences of clinically relevant food sensitization, were higher for all foods tested in the group less than 1 year of age, and were significantly higher in moderate to severe AD compared to mild AD in infants and young children. In summary, presence of food specific IgE is prevalent in infants and young children with AD, and clinically relevant food sensitization is important in Korean infants and children with moderate to severe AD.
Child, Preschool ; Dermatitis, Atopic/*immunology ; Egg Hypersensitivity/epidemiology ; Female ; Food Hypersensitivity/diagnosis/*epidemiology ; Humans ; Immunoglobulin E/blood ; Infant ; Male ; Milk Hypersensitivity/epidemiology ; Peanut Hypersensitivity/epidemiology ; Soybeans/immunology

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.
Anaphylaxis ; diagnosis ; Child ; Child, Preschool ; Egg Hypersensitivity ; Fish Products ; Food Hypersensitivity ; diagnosis ; epidemiology ; prevention & control ; Humans ; Infant ; Infant, Newborn ; Milk Hypersensitivity ; Peanut Hypersensitivity ; Singapore ; epidemiology ; Surveys and Questionnaires

The prevalence and patterns of food allergy are highly variable in different parts of the world. Differences in food allergy epidemiology may be attributed to a complex interplay of genetic, epigenetic, and environmental factors, suggesting that mechanisms of food allergy may differ in various global populations. Genetic polymorphisms, migration, climate, and infant feeding practices all modulate food allergy risk, and possibly also the efficacy of interventions aimed at primary prevention of food allergy development. Approaches to diagnosis, treatment, and prevention of food allergy should thus be tailored carefully to each population's unique genetic and environmental make-up. Future research in the context of food allergy prevention should focus on elucidating factors determining differential responses between populations.
Climate ; Dermatitis, Atopic ; Diagnosis ; Epidemiology ; Epigenomics ; Food Hypersensitivity* ; Genetics ; Humans ; Infant ; Polymorphism, Genetic ; Prevalence ; Primary Prevention

OBJECTIVEFood allergy as one of social health problems has gained more attention of people. However, few reports on prognosis of food allergy, the relation between infant food allergy and other allergic diseases, and factors affecting prognoses of infant food allergy in China. The present study was designed to investigate the evolution of infancy food allergy and to explore predicting factors of the tolerance to these foods and factors of other allergic diseases to provide a clue for managing children with food allergy reasonably and to improve their prognoses.

METHODSTotally 119 children with food allergy during infancy, who were diagnosed in the Department of Primary Child Care, Children's Hospital, Chongqing University of Medical Sciences from January 2000 to June 2003, were studied retrospectively by analyzing the follow-up data before March 2004. The occurrence of food tolerance and other allergic diseases were counted. Kaplan-Meier methods were used to calculate the cumulative tolerance probability. And the predicting factors of persistent food allergy and influential factors of other allergic diseases were analyzed by unconditional Logistic regression models.

RESULTSThe cumulative tolerance probabilities of cow's milk and egg were 42% and 31% one year after diagnosis respectively, 63% and 62% 2 years later, 77% and 80% 3 years later, and 100% after 4 years. And the severity of skin prick test reactions to cow's milk and egg was the predicting factor for persisting hypersensitivity to cow's milk and egg (OR = 2.535, 95% CI: 1.159-5.543; OR = 2.654, 95% CI: 1.302-5.410, P < 0.05). Thirteen cases presented with hypersensitivity to other foods (15.6 +/- 6.1) months after the diagnosis was confirmed, and the risk factor was the long-lasting hypersensitivity to egg (OR = 6.109, 95% CI: 1.818-20.527, P < 0.05). After 4 cases and 15 cases were diagnosed as allergic rhinitis and asthma, respectively, (16.8 +/- 8.3) months after diagnoses and the risk factors were the long-lasting hypersensitivity to egg and the respiratory symptoms (OR = 3.596, 95% CI: 1.429-9.045; OR = 4.235, 95% CI: 1.152-15.563, P < 0.05).

CONCLUSIONAt least 75% of children with egg or cow's milk allergy could develop tolerance to egg or cow's milk within 3 years after diagnoses; 10.9%, 12.6% and 3.4% of children with food allergy suffered from other food allergy, asthma and allergic rhinitis. Strengthening the screening and management of children at high risk for persistent food allergy will contribute to improvement of the prognoses of food allergy.

Child, Preschool ; China ; epidemiology ; Female ; Food Hypersensitivity ; diagnosis ; epidemiology ; immunology ; Humans ; Immune Tolerance ; Infant ; Male ; Prognosis ; Retrospective Studies ; Risk Factors

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 of 3 of 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 year of age. Wheat has become another leading food besides cow's milk and egg in causing positive OFC in younger children in Thailand.
Asia ; Child ; Diagnosis ; Epidemiology ; Food Hypersensitivity ; Hospitals, Teaching ; Humans ; Hypersensitivity ; Immunoglobulin E ; Medical Records ; Milk ; Ovum ; Prevalence ; Retrospective Studies ; Shellfish ; Skin ; Thailand ; Triticum ; Wheat Hypersensitivity

Scombroid fish poisoning (SFP) is a form of histamine food poisoning caused by the ingestion of improperly stored fish. The term “scombroid” derives from the family name of the fish family first implicated, such as tuna and mackerel. On the other hand, non-scombroid fish species, such as sardine and herring, can also cause histamine poisoning. The histamine is converted from histidine by a bacterial enzyme in the causative fish. Because the symptoms of SFP can easily be confused with food allergies, it is believed to have been significantly under-reported. In 2016, an outbreak of SFP occurred among primary school students who had eaten yellowtail steak in Korea. The most common findings consisted of a rapid onset of flushing of the face and trunk, erythematous and urticarial rash, diarrhea, and headache occurring soon after consuming the spoiled fish. Usually, the course is self-limiting and antihistamines can be used successfully to relieve symptoms, but several life-threatening SFP cases have been reported. Clinical toxicologists should be familiar with SFP and have competency to make a differential diagnosis between fish allergy and histamine poisoning. SFP is a histamine-induced reaction caused by the ingestion of histamine-contaminated fish, whereas a fish allergy is an IgE-mediated reaction. This review discusses the epidemiology, pathophysiology, diagnosis, treatment, and preventive measures of SFP.
Diagnosis ; Diagnosis, Differential ; Diarrhea ; Eating ; Epidemiology ; Exanthema ; Flushing ; Food Hypersensitivity ; Foodborne Diseases ; Hand ; Headache ; Histamine Antagonists ; Histamine ; Histidine ; Humans ; Hypersensitivity ; Korea ; Perciformes ; Poisoning ; Tuna

In Korea, common whelk (Buccinum undatum) is a popular edible shellfish. The aim of this study was to observe the sensitization rate to common whelk and to characterize its allergens. We carried out skin prick test (SPT) in 1,700 patients with various allergic diseases. Specific IgE were detected by ELISA in the patient sera and ELISA inhibition tests were conducted. IgE-binding components were identified by means of SDS-PAGE and IgE-immunoblotting. The effects of diges-tive enzymes were evaluated in both raw and thermally treated extracts. SPT to common whelk was positive (> or =2+) in 83 (4.9%) patients studied. Twenty-four (38.7%) out of 62 SPT positive patients had high serum specific IgE to common whelk. ELISA inhibition test showed significant inhibitions by abalone as well as by common whelk. IgE-immunoblotting demonstrated three IgE-binding components (40, 71, 82 kDa), which were digested by simulated intestinal fluid and moderately digested by simulated gastric fluid, and the digestibility of allergens remained unchanged after thermal treatment. In conclusion, IgE-sensitization rate to com-mon whelk was 4.9% in allergy patients. IgE-immunoblotting demonstrated three IgE-binding components, which were degraded by digestive enzymes. Further studies are needed to evaluate the clinical significance of the sensitized patients to common whelk.
Allergens/immunology ; Animals ; Comparative Study ; Cookery ; Digestion/*physiology ; Food Handling/methods ; Food Hypersensitivity/diagnosis/*epidemiology/*immunology/metabolism ; Heat ; Humans ; Immunoglobulin E/*immunology/metabolism ; Intestines/enzymology ; Korea/epidemiology ; *Mollusca ; Research Support, Non-U.S. Gov't ; Shellfish/*adverse effects ; Skin Tests ; Stomach/enzymology

INTRODUCTIONThe prevalence of perceived food allergies exceeds that of true food allergies. Unnecessary food avoidance may increase parental and patient anxiety, reduce quality of life and increase the risk of nutritional deficiency. An oral food challenge (OFC) can provide an objective measure regarding the presence or absence of food allergies in a child. This study reviews the indications for and outcomes of OFCs performed on children.

METHODSA retrospective review was performed on all children who underwent OFCs at the Allergy Unit of the National University Hospital, Singapore, over a three-year period.

RESULTSA total of 197 OFCs were performed among 58 patients (34 male, 24 female). Most of the tests were for allergies to tree nuts (n = 107). Among the OFCs, 43.1% were for foods that were avoided and never eaten due to perceived food allergies, 25.9% were for foods that had previously resulted in positive skin prick tests (SPTs) and/or immunoassay results, 16.2% were for foods thought to worsen eczema and 14.7% were for foods thought to have caused a previous reaction. Of all the OFCs, 5% were positive, although adverse reactions were mostly cutaneous. Challenge-positive patients had either positive SPTs (wheal > 3 mm) or raised serum immunoglobulin E levels to specific foods that they reacted to during the challenges. No episodes of anaphylaxis were reported after the challenge. Most of the patients were able to safely introduce the avoided foods into their diets.

CONCLUSIONOFCs provide an objective assessment for suspected food allergies.

Adolescent ; Child ; Child, Preschool ; Female ; Follow-Up Studies ; Food ; adverse effects ; Food Hypersensitivity ; diagnosis ; epidemiology ; Humans ; Male ; Prevalence ; Quality of Life ; Retrospective Studies ; Singapore ; epidemiology ; Skin Tests ; Tertiary Care Centers ; Time Factors

OBJECTIVETo investigate the seasonal influence on the diagnosis of food allergy in children under 3 years of age.

METHODThe data of epidemiological studies about food allergy of children under 3 years of age attending routine well-baby checks at the Department of Primary Child Care, Children's Hospital of Chongqing Medical University in the winter and summer, 2009, including questionnaires, results of skin prick test (SPT), food elimination and oral food challenge (OFC) were analyzed. All the data were analyzed by SPSS 17.0.

RESULTThe age and sex distribution, and both the rates of the drop-out in two studies were similar. Ninety infants were positive for SPT, 40 infants were positive for OFC, and 31 infants dropped out in winter; while 65 infants were positive for SPT, 25 positive for OFC, and 31 dropped out in summer. The percentage of positive SPT in the children performed in winter was higher than that in summer (14.9%, 90/603 vs 10.7%, 65/607) (P = 0.028). Skin prick test accuracy was similar when the studies were performed in winter and in summer [sensitivity 0.85 and 0.84, positive predictive value (PPV) 0.54 and 0.47, negative predictive value (NPV) 0.99 and 0.99]. The prevalence of food allergy in the children studied in winter was higher than that in summer (7.0% vs 4.3%), but the difference was not significant. After correcting the prevalence for dropout children, the prevalence of food allergy (FA) investigated in winter was significantly higher than that in summer (9.3% vs 5.9%). The results of circular distribution analysis showed the date of birth corresponding to estimated value of peak point of SPT in winter were not consistent with it in summer, so was OFC. Either the results of skin prick test or oral food challenge in two studies were not correlated with the seasons of birth.

CONCLUSIONOur data showed that the rates of positive SPT and the prevalence of food allergy were correlated with the seasons, but the seasons of birth did not influence the results of skin prick test or oral food challenge in children, while the real age of children were related to them.

Age Factors ; Child, Preschool ; China ; epidemiology ; Female ; Food Hypersensitivity ; diagnosis ; epidemiology ; immunology ; Humans ; Infant ; Infant, Newborn ; Male ; Predictive Value of Tests ; Prevalence ; Seasons ; Sensitivity and Specificity ; Severity of Illness Index ; Skin Tests ; methods ; Surveys and Questionnaires