Food allergy in children suffering from atopic eczema

Whilst the association between eczema and food allergy is well established, the role of dietary manipulation in children with eczema remains controversial. These case histories highlight the differing outcomes that dietary manipulation may have in an infant with early onset, severe eczema and an older child with milder eczema. Management strategies and the evidence to support them are presented, followed by a review of clinical recommendations.     

Role of food allergy in childhood atopic dermatitis

The interplay between atopic dermatitis (AD) and food allergy is complex and subject to significant misconceptions both by the general public and the medical community. Childhood AD is a very prevalent disorder. In its moderate and severe forms, AD is a challenging disorder to manage from the perspective of the child, parent and treating doctor. As AD is one of the disease manifestations of atopy, it is unsurprising that many children with AD also have a coexisting IgE‐mediated food allergy. It is a common misconception that food allergy is causal in the setting of AD. However, in a proportion of sufferers, food allergy does play a role in triggering or exacerbating pre‐existing AD by immune‐mediated mechanisms and potentially by non‐immune mechanisms. It is, therefore, important to differentiate causality, co‐existent disease and disease modifiers in this context. This paper seeks to clarify the role of food allergy in childhood AD, and to outline a rational framework for the diagnosis and approach to food allergy in the context of the management of a child with problematic AD.     

Comparison of fecal microflora in children with atopic eczema/dermatitis syndrome according to IgE sensitization to food

Atopic eczema/dermatitis syndrome (AEDS) commonly often arises during early infancy. In several intervention studies a beneficial influence on AEDS course of certain intestinal bacteria, administered as 'probiotics', has been described. To evaluate the possible role of the natural intestinal microflora in children with allergic eczema/dermatitis syndrome regarding immediate type hypersensitivity to food allergens, children with food allergy (AAEDS, n = 68) have been compared with children without detectable food allergy (NAEDS, n = 25). All children (n = 93) in preschool age, mean age of 2.6 (+/-1.8) years, diagnosed with AEDS who were treated as inpatients in 2003 in a dermatological hospital were included. The correlation between fecal microflora, parasites and specific immunoglobulin E (IgE) antibodies against common food allergens was analyzed. A similar composition of intestinal microflora in children with AAEDS and NAAEDS was found. The food allergens that were most frequently detected were egg white, cow milk, casein, peanut and hazelnut. Furthermore, a significant association between IgE sensitization against important food allergens and components of the fecal microflora could not be demonstrated. With aging changes occur in the intestinal microbiota [Proteus/Klebsiella and age (rho = -0.607) and Enterococcus and age (rho = -0.428)]. In two subjects of the AAEDS group Blastocystis hominis was found. The composition of natural intestinal microflora in children with AAEDS and NAAEDS was similar. Hence, there is no evidence of a role of the intestinal microflora with regard to the development of infant (food) allergy in children with AEDS. The possible consequences for allergic diseases later in life require further investigation.     

Helicobacter pylori seropositivity in children with atopic dermatitis as sole manifestation of food allergy

A positive association between Helicobacter pylori antibodies and food allergy presenting with gastrointestinal symptoms has recently been reported. A subset of a H. pylori strain possesses an antigen, CagA, as a virulence factor. Anti‐ H. pylori and anti‐CagA IgG titre have been determined in children with atopic dermatitis (AD) as the sole clinical manifestation of food allergy. In this study, thirty patients with AD as the sole clinical manifestation of food allergy were examined (group A). For comparative purposes, 30 patients affected by food allergy with gastrointestinal symptoms (group B) and 30 affected by atopic asthma (group C) were studied. Anti‐ H. pylori and anti‐CagA immunoglobulin G (IgG) were determined in all individuals by means of the enzyme‐linked immunosorbent assay. The anti‐ H. pylori IgG titre was significantly higher in group A and group B vs. group C (p < 0.05); no significant difference was detected between group A and group B (p > 0.05). No significant difference in anti‐CagA titre was found between the groups. These data demonstrate a positive association between H. pylori antibodies and AD as the sole manifestation of food allergy. Further investigations are needed to evaluate the cause–effect relationship between H. pylori seropositivity and AD.     

特应性皮炎婴幼儿IgE介导食物过敏的随访研究

目的探讨IgE介导的食物过敏在特应性皮炎中的作用及其转归。方法对86例深圳地区特应性皮炎患儿进行混合食物组过敏原筛查(fx5E)检测,阳性者进一步检测6种常见食物(鸡蛋白、牛奶、鱼、小麦、花生、大豆)过敏原特异性IgE(sIgE)。对sIgE阳性患儿建议采取过敏食物回避措施,随访6个月和2年。结果 86例患儿中,36例(42%)有IgE介导的食物过敏,牛奶和(或)鸡蛋白为主要过敏原,分别占70%和64%。31例患儿完成了2年随访,食物sIgE检测为1级的13例患儿目前均无过敏症状;13例2级患儿再次进食过敏食物,仍有5例出现症状;7例3级以上过敏患儿,目前再次进食过敏食物,均出现症状。结论 IgE介导的食物过敏是引起婴幼儿特应性皮炎的重要原因,牛奶和(或)鸡蛋白是主要的过敏食物。回避过敏食物可以明显缓解症状,轻度过敏者症状随年龄增长可以消失,过敏程度越高,再次接触过敏食物出现症状的可能性越大。     

Recent advances in epidemiology and prevention of atopic eczema

Atopic dermatitis (AD), named also atopic eczema, is a chronic relapsing inflammatory skin disease with a considerable social and economic burden. The primum movens of AD is in most cases a genetic and/or immune‐supported defect of the skin barrier, facilitating penetration and sensitization to food or airborne allergens, as well as infections by Staphylococcus aureus, herpes simplex virus, or other microbes. New pathogenetic concepts have generated new approaches to prevention and therapy of AD. In particular, the daily use of emollients in newborns at high risk of AD has shown interesting results, with a reduction in the cumulative incidence of AD ranging from 32% to 50% of the treated infants. On the other hand, the AD preventive efficacy of food and/or inhalant allergen avoidance has been questioned, and supplementation strategies (vitamin D, probiotics, or other compounds) need to be further investigated.     

Proposal for a standardized interpretation of the atopy patch test in children with atopic dermatitis and suspected food allergy

The interpretation of the atopy patch test (APT) to foods is not standardized. This study aimed to validate the reading of the APT in terms of the diagnostic accuracy of individual skin signs. Eighty-seven children (mean age 2.4 +/- 2.5 yr, range 0.5-13.5; 57 male) with atopic dermatitis (AD) and suspected food allergies underwent APT to cow's milk, hen's egg, wheat and soy. Twelve-millimetre Finn chambers were applied for 48 h, and results were read after 48 and 72 h. Skin changes were graded for erythema, induration, papule formation and 'crescendo' phenomenon (increase of skin sign severity from 48 to 72 h). Food allergy was assessed by double blind, placebo-controlled food challenges (DBPCFC). Sensitivity, specificity and predictive values were calculated for each skin signs in relation to challenge outcome. Of 165 DBPCFC children, 75 (45%) were positive. The combination of any skin induration plus papules (seven or more), or of moderate erythema plus any induration plus seven or more papules had a positive predictive value (PPV) and specificity for the challenge outcome of 100%; however, the sensitivity was low (8% and 15%). The best diagnostic accuracy for single signs was found for induration beyond the Finn chamber margin (PPV 88%, specificity 99%, sensitivity 9%) and presence of at least seven papules (PPV 80%, specificity 96% sensitivity 21%). Presence of both induration and of at least seven papules at 72 h were the APT skin signs with the greatest diagnostic accuracy for food allergy in children with AD.     

Association of food allergy with asthma severity and atopic diseases in Jewish and Arab adolescents

Aim: To investigate the prevalence of reported food allergy and its association with atopic diseases and asthma severity among Jewish and Arab adolescents. Subjects and methods: The self‐report questionnaire of the International Study of Asthma and Allergies in Childhood (ISAAC) was administered to adolescents aged 13–14 years from randomly selected junior high schools in Israel. Questions regarding food allergy were added. Results: A total of 11 171 questionnaires were available for analysis. Food allergy was reported by 3.6% of participants: 1.9% milk, 0.6% egg, 0.6% peanut and 0.4% sesame. On multivariate analysis, food allergy was strongly associated with current asthma (OR, 2.5; 95% CI, 1.8–3.3), atopic eczema (OR, 3.2; 95% CI, 2.4–4.3) and allergic rhinitis (OR, 2.4; 95% CI, 1.8–3.1). Arabs were significantly more allergic to peanut (OR, 2.5; 95% CI, 1.5–4.1), egg (OR, 3.5; 95% CI, 2.1–5.9) and sesame (OR, 2.3; 95% CI, 1.2–4.5) than Jews, and less allergic to milk (OR, 0.6; 95% CI, 0.4–0.9). Asthmatic subjects with food allergy had significantly more parameters of severe asthma than those without food allergy (p < 0.001). Conclusions: The prevalence of allergy to specific foods differs between Jews and Arabs. Asthmatic adolescents with food allergy report more severe asthma than those without food allergy.     

上海地区720例特应质儿童食物过敏临床分析

目的 探讨上海地区特应质儿童中食物过敏的发病情况和临床特点,以及食物过敏与其他过敏性疾病的关系.方法 采用国际上经典的食物过敏诊断方法 进行研究,对2007年7月-2008年7月因过敏症状在上海儿童医学中心过敏/免疫专科就诊的720例2个月～17岁特应质儿童,进行病史收集、皮肤点刺试验、排除性饮食试验和开放式食物激发试验.结果 最后确诊食物过敏59例(发生率8.19%).初次发生食物过敏的平均年龄为(0.40±0.33)岁.引起过敏的主要食物为鸡蛋(5.83%)、牛奶(2.78%),虾(1.67%)、鱼(1.25%);3岁以下儿童对鸡蛋过敏多见,≥3岁对虾过敏多见(P<0.01);94.92%的儿童对一种或二种食物过敏.食物过敏100%可引起皮肤症状,25%的特应质儿童因食物过敏引起湿疹;消化道症状发生率为3.39%;呼吸道症状发生率为1.69%;过敏性休克发生率为1.69%.≥3岁仍食物过敏的儿童吸入性过敏原阳性、患哮喘和过敏性鼻炎/结膜炎的人数均显著多于3岁以下的食物过敏儿童(P<0.01).结论 上海地区的特应质儿童中,食物过敏的发生率高,发生年龄小.对有皮肤过敏症状的儿童,应首先考虑食物过敏可能.早期诊断并阻断食物过敏,可预防其他严重过敏性疾病的发生.     

Food allergy and atopic dermatitis: Prediction,progression, and prevention

The rising burden of allergic diseases in childhood requires a compelling need to identify individuals at risk for atopy very early in life or even predict the onset of food allergy and atopic dermatitis since pregnancy. The development and clinical phenotypes of atopic diseases in childhood depend on a complex interaction between genetic and environmental factors, such as allergen exposure, air pollution, and infections. Preventive strategies may include avoidance measures, diet supplements, and early complementary food introduction. Overall, the management of allergic diseases has been improving to date toward a patient's tailored approach. This review will cover the current understanding of risk factors, prediction, and management of food allergy and atopic dermatitis in childhood and discuss how these may contribute to the modification of the natural history of food allergy and atopic dermatitis.     

白细胞介素10受体1在食物过敏儿童外周血T淋巴细胞中的表达

目的　研究白细胞介素10受体1（IL-10R1）在食物过敏儿童外周血T淋巴细胞的表达及其临床意义。方法　选择2017-07-01至2017-12-31在北京大学第三医院儿科食物过敏门诊诊断为食物过敏的50例患儿作为食物过敏组,选择同期在北京大学第三医院儿童健康发展中心行健康体检的25名儿童作为对照组。采用流式细胞技术检测IL-10R1在两组儿童外周血CD4+T及CD8+T淋巴细胞表达阳性率及平均荧光强度值（MFI）。同时比较IL-10R1在过敏原特异性IgE阳性与阴性食物过敏患儿外周血CD4+T及CD8+T淋巴细胞表达阳性率及MFI。根据食物过敏患儿症状、体征严重程度进行赋值评分,分析食物过敏患儿IL-10R1在外周血CD4+T及CD8+T淋巴细胞表达阳性率与食物过敏症状、体征评分有无相关性。结果　IL-10R1在食物过敏组患儿外周血CD4+T及 CD8+T淋巴细胞表达阳性率和MFI均低于对照组,IL-10R1在食物过敏组CD4+T淋巴细胞表达阳性率和MFI中位数分别为40.23、 12.18; 在对照组CD4+T淋巴细胞表达阳性率和MFI中位数分别为45.32、 17.69（Z值分别为-2.506、 -5.457;P值分别为0.012、 0.000）。IL-10R1在食物过敏组CD8+T淋巴细胞表达阳性率和MFI中位数分别为34.50、 12.47;对照组CD8+T淋巴细胞IL-10R1表达阳性率和MFI中位数分别为39.46、 17.28（Z值分别为-4.035、 -5.226; P值分别为0.000、 0.000）。IL-10R1在过敏原特异性IgE阳性与阴性患儿外周血CD4+T及CD8+T淋巴细胞表达阳性率及MFI没有差异。食物过敏患儿IL-10R1在外周血CD4+T及CD8+T淋巴细胞表达阳性率与食物过敏症状、体征评分无相关性。结论　IL-10R1在外周血CD4+T淋巴细胞和CD8+T淋巴细胞表面表达减少可能与食物过敏发病有关;IL-10R1在外周血CD4+T淋巴细胞和CD8+T淋巴细胞表面表达在IgE和非IgE介导的食物过敏发病过程中均起作用;IL-10R1在外周血CD4+T淋巴细胞和CD8+T淋巴细胞表面表达可能与食物过敏发病严重程度无关。     

Fish and shellfish allergy in children: Review of a persistent food allergy

The increased consumption of fish and shellfish has resulted in more frequent reports of adverse reactions to seafood, emphasizing the need for more specific diagnosis and treatment of this condition and exploring reasons for the persistence of this allergy. This review discusses interesting and new findings in the area of fish and shellfish allergy. New allergens and important potential cross‐reacting allergens have been identified within the fish family and between shellfish, arachnids, and insects. The diagnostic approach may require prick to‐prick tests using crude extracts of both raw and cooked forms of seafood for screening seafood sensitization before a food challenge or where food challenge is not feasible. Allergen‐specific immunotherapy can be important; mutated less allergenic seafood proteins have been developed for this purpose. The persistence of allergy because of seafood proteins’ resistance after rigorous treatment like cooking and extreme pH is well documented. Additionally, IgE antibodies from individuals with persistent allergy may be directed against different epitopes than those in patients with transient allergy. For a topic as important as this one, new areas of technological developments will likely have a significant impact, to provide more accurate methods of diagnosing useful information to patients about the likely course of their seafood allergy over the course of their childhood and beyond.     

Trends in the prevalence and severity of asthma, rhinitis and atopic eczema in 6- to 7- and 13- to 14-yr-old children from the north-east of England

The aims of the present study were to assess time trends in symptoms of asthma, rhinitis and atopic eczema among children in the north-east of England. Two cross- sectional surveys 6 yr apart, 6- to 7- and 13- to 14 yr of age, using the International Study of Asthma and Allergies in Childhood, core questionnaire were performed. There was a general increase in symptoms for all the three conditions in both the age groups. In the age group 6- to 7 yr, the increase was generally the same in boys and girls, while in the age group 13- to 14 yr, the increase was generally more marked among boys. In the younger age group, indices related to lifetime diagnosed ever had asthma and having hay fever increased in girls but not in boys, while indices related to lifetime diagnosis of ever having eczema increased in boys and girls. In the older age group, indices related to lifetime diagnosis of ever had asthma slightly increased in boys but did not change in girls, while lifetime diagnosis of ever having hay fever slightly decreased in girls but did not change in boys. The prevalence of lifetime diagnosis of ever having eczema increased in boys and girls. Changes observed in the present study could be related to the changes in lifestyle or environmental factors, awareness or management of symptoms.