Prevalence and Clinical Impact of IgE-Mediated Food Allergy in School Children With Asthma: A Double-Blind Placebo-Controlled Food Challenge Study

PURPOSE: Recent studies indirectly suggest a possible link between food allergy (FA) and asthma. Most of them have evaluated the occurrence of FA in asthmatic children, especially in the first year of life, using questionnaire-based studies or specific IgE (sIgE) assay. The aim of this study was to evaluate the prevalence and clinical impact of IgE-mediated FA in school children with asthma using a double-blind placebo-controlled food challenge (DBPCFC). METHODS: The study group consisted of school children with atopic asthma who were admitted to the Department of Pediatric Allergology, Gastroenterology and Nutrition, Medical University of Lodz, for the evaluation of food hypersensitivity. The diagnosis of FA was established using questionnaires, sIgE analysis, and the DBPCFC. Asthma severity and asthma control state were also assessed. RESULTS: A relationship between consumed food and complaints was reported in 180 children (49.7%). Seventy children (19.3%) were sensitized to food allergens. IgE-mediated FA was confirmed in 24 children (6.6%), while 11 children (3%) demonstrated respiratory symptoms. Food-induced asthma exacerbations were observed in 9 patients (2.5%). Statistically significant differences in the prevalence of atopic dermatitis (P<0.002), urticaria (P<0.03), digestive symptoms (P<0.03), rhinitis (P<0.02), sIgE level (P<0.001), positive family history of atopy (P<0.001) and FA in history (P<0.001) were found between asthmatic children with FA and those without. Children with food-induced asthma exacerbations demonstrated significantly greater severity, poorer controls, and worse morbidity compared to those without. CONCLUSIONS: Although food-induced respiratory reactions in children with asthma were rare, they were classified as severe and associated with worse morbidity, greater severity, and poorer control. As the most commonly observed symptoms were coughing and rhinitis, which can be easily misdiagnosed, a proper diagnosis is essential for improving the management of both clinical conditions.

Diagnosis and Treatment of Food Allergy in Children / 소아알레르기및호흡기학회지

Food allergy is a common allergic manifestation in early childhood. However, some medical practitioners remain sceptical about the role of food allergies in a number of clinical syndromes, such as atopic dermatitis, colic and gastrooesophageal reflux in infancy, despite increasing evidences that food allergy can contribute to these conditions. Symptoms usually begin in the first 2 years of life, often after the first exposure to the known food. Diagnosis is made using medical history and can usually be detected by skin prick testing (SPT) or measuring food-specific serum IgE antibody levels. But to obtain final confirmation a double blind controlled food challenge (DBPCFC) must be performed. Delayed-onset reactions (occurring within several hours to days after ingestion) are often difficult to diagnose. The patients usually show negative SPT, so elimination or challenge protocols are required to make a definitive diagnosis. These forms of food allergy are not usually associated with anaphylaxis. Prevention and treatment are based on the avoidance of the culprit food. Children often develop tolerance to cows milk, egg, soy and wheat by school age, whereas allergies to nuts and shellfish are more likely to be lifelong. This article will help general practitioners and other clinicians understand the principles of diagnosis and management of food allergy in childhood, and suggests when to refer patients to specialist.