The role of dietary interventions in the prevention of IgE‐mediated food allergy in children

Over the last 30 years, the prevalence of food allergy has been on the rise and remains a disease that can have a significant impact on the quality of life of children and their families. There are several hypotheses that have been suggested to account for the increasing prevalence, but this review will focus on the impact that dietary factors have on food allergy development. In the past food allergy, prevalence has largely focused on allergen avoidance; however, there is increasing evidence from interventional studies that have shown that early introduction to potential food allergens may have a beneficial role in allergy prevention. This review aims to look at the evidence in support of early introduction of allergens into infant diets to prevent against the development of food allergy.     

Skin prick test predictive value on the outcome of a first known egg exposure in milk-allergic children

Children with milk allergy have higher incidence of other food allergies, especially egg allergy. The objective of this study was to ascertain the accuracy of the prick test in children with IgE-mediated milk allergy for diagnosing egg allergy. Children under the age of 1 yr who came consecutively to Allergy Department 2003–05, and were diagnosed with IgE-mediated milk allergy were selected for this study. Egg introduction was completely avoided until the age of 14 months when clinical history, skin prick tests (SPT), specific-IgE antibodies determination and egg challenge test were performed. One hundred and four milk-allergic children were included. At least one positive prick test to any egg allergen was found in 65 out of the 104 (62.5%). Thirty-eight (36.5%) were allergic to egg proteins as well. Prick tests with egg white and ovomucoid (OVM) had the best diagnostic performances showing the largest areas under the receiver operating characteristic curve. The optimal diagnosis cut-off point was 6 mm for egg white and 5 mm for OVM. The positive likelihood ratios for these cut-off points were: 2.95 (95% CI: 1.74–4.99) for egg white prick test, and 20 (95% CI: 2.9–143.7) for OVM prick test. Children with specific IgE-mediated cow's milk allergy must be closely followed as a risk group for egg allergy. Early diagnosis is necessary and the SPT has shown itself to be a very useful tool for diagnosing immediate IgE reactions to egg on first known exposure.     

Non‐IgE‐mediated gastrointestinal food allergies in children

Non‐IgE‐mediated gastrointestinal food allergic disorders (non‐IgE‐GI‐FA) including food protein‐induced enterocolitis syndrome (FPIES), food protein‐induced enteropathy (FPE), and food protein‐induced allergic proctocolitis (FPIAP) are relatively uncommon in infants and young children, but are likely under‐diagnosed. Non‐IgE‐GI‐FA have a favorable prognosis, with majority resolving by age 3–5 years. Diagnosis relies on the recognition of symptoms pattern in FPIAP and FPIES and biopsy in FPE. Further studies are needed for a better understanding of the pathomechanism, which will lead eventually to the development of diagnostic tests and treatments. Limited evidence supports the role of food allergens in subsets of constipation, gastroesophageal reflux disease, irritable bowel syndrome, and colic. The immunologic pathomechanism is not fully understood and empiric prolonged avoidance of food allergens should be limited to minimize nutrient deficiency and feeding disorders/food aversions in infants.     

Protein‐losing enteropathy and erythema caused by egg allergy in a breast‐fed infant

A 4‐month‐old breast‐fed girl presented with poor weight gain, and had edema and repeated erythema from 5 months of age. The diagnosis of protein‐losing enteropathy (PLE) was confirmed on ^99mTc‐labeled human serum albumin scintigraphy. Specific IgE radioallergosorbent test was class 3 for egg white, class 2 for egg yolk, and negative for other foods. Elimination of egg from the mother's diet and oral epinastine hydrochloride treatment and sodium cromolyn improved hypoalbuminemia, hypogammaglobulinemia, and erythema. PLE and erythema coincident in a breast‐fed infant suggests that IgE‐mediated allergy may play a leading role in some cases of PLE due to food allergy in infants.     

Parents' estimate of food allergy prevalence and management in Italian school‐aged children

Background: Despite the increasing prevalence of food allergy, few studies have assessed the prevalence of perceived food‐induced symptoms among school‐aged children. There is also a paucity of data on how children with food reactions are managed. We investigated the frequency and characteristics of perceived food reactions in school‐aged children. Methods: Children aged 5–14 years were included in this cross‐sectional study. A standardized self‐administered questionnaire on food reactions was handed out to 900 parents. Results: We achieved a response rate of 69%. The lifetime prevalence of parental perceived allergic reactions to food was 10.5%; the point prevalence was 1.6%. Medical care included a call to a general practitioner in 54% of cases, self‐management in 37%, an emergency call in 6%, and hospitalization in 3%. Antihistamines were administered in 45% of food reactions, topical steroids in 24%, oral or parenteral steroids in 16%, and epinephrine in 1.5%. In children who reported food reactions, skin prick tests for foods were performed in 54% of cases; the oral food challenge test was performed in 7.5%. Conclusion: Parent perception of food allergic disorders is common in school‐aged children. Few children have undergone diagnostic tests to ascertain clinical food hypersensitivity. This is warranted to avoid unnecessarily restricted diets. Efforts should be made to train primary care physicians to manage food‐allergic children.     

An evaluation of the diagnostic value of different skin tests with egg in clinically egg-allergic children having atopic dermatitis

Skin testing is a common diagnostic procedure in food allergy, but the final diagnosis of food allergy is based on the clinical response to food challenge. We studied the value of the skin prick-prick test (SPT), skin application food test (SAFT) and atopy patch test (APT) with fresh egg extract in diagnosing egg allergy. Ten clinically egg-allergic children with atopic dermatitis (AD; age 10 months to 8.4 yr, mean 3.4 yr) and 10 egg-tolerant children with and 10 without AD (age 2.4-11 yr, mean 5.5 yr) participated. In SAFT several false-negative reactions were seen, whereas all clinically egg-allergic children were positive in SPT and 40-60% in APT. In APT and in SPT false-positive reactions to egg were observed. In this study comprising a small number of patients including control subjects, neither SAFT nor APT with fresh whole egg extract were able to increase the diagnostic accuracy in detecting egg-allergic children with AD compared with SPT.