Nahrungsmittelallergie und atopische Dermatitis

Food allergy can be observed in a subgroup of atopic patients, such as patients suffering from atopic dermatitis (AD). Approximately 30?% of children with moderate or more severe forms of AD and sensitization to food allergens show associated clinical symptoms of hypersensitivity. Many patients with AD or parents of affected children suspect food as being relevant trigger factors for AD. Patients who actually benefit from elimination diets must be identified by means of validated diagnostic procedures. In turn malnutrition and associated limitations of quality of life should be avoided in those patients for whom food allergy could be excluded. As determination of specific IgE, results of skin prick tests and the patient history often do not correlate with eczematous reactions to food allergens, oral food challenges supervised by allergologists still represent the diagnostic gold standard for elucidating the clinical relevance of sensitization. As eczematous lesions often deteriorate after a period of 6–48 h after food challenge, examination of the skin should also be performed on the following day. Moreover, in patients with AD, the challenge with a food allergen should be performed in a repeated test over 2 days.     

Natural history of food hypersensitivity in children with atopic dermatitis

Patients with atopic dermatitis and food hypersensitivity who were adhering to an elimination diet underwent repeat double-blind, placebo-controlled oral food challenges annually for follow-up of their food allergy. After 1 year, 19 of 75 patients lost all signs of clinical food hypersensitivity (15 of 45 patients allergic to one food, and 4 of 21 allergic to two foods). Of the individual foods, 38 of 121 no longer elicited symptomatic responses. After 2 years, patients underwent a second rechallenge; 4 of 44 patients tested lost their clinical food hypersensitivity. In 20 patients undergoing a third rechallenge, no food hypersensitivity was lost. Loss rate of food hypersensitivity varied among foods; after 1 year, there was a 26% loss of symptomatic food allergy to five major allergens (egg, milk, soy, wheat, and peanut) compared with a 66% loss rate to other food allergens. Loss of symptomatic allergy was not affected by the patient's age at diagnosis, except with milk allergy, for which older patients were more likely to lose clinical food hypersensitivity (p less than 0.05). Total serum IgE and prick skin tests were not useful for predicting loss of symptomatic food hypersensitivity. There was no significant decrease in skin test wheal size corresponding to loss of clinical food hypersensitivity. Patients developing only skin symptoms during the initial challenge were most likely to lose symptomatic food hypersensitivity.     

Are avoidance diets still warranted in children with atopic dermatitis?

Nearly 40% of children with moderate-to-severe atopic dermatitis (AD) have IgE-mediated food allergy (FA). This clinical observation has been extensively documented by experimental data linking skin inflammation in AD to FA, as well as by food challenges reproducing symptoms and avoidance diets improving AD. Although food avoidance may improve AD, avoidance diets do not cure AD, may even have detrimental effects such as progression to immediate-type allergy including anaphylactic reactions, and may significantly reduce the quality of life of the patient and the family. AD care should focus upon optimal medical management, rather than dietary elimination. Food allergy testing is primarily indicated when immediate-type allergic reactions are a concern. In recalcitrant AD, if food is being considered a possible chronic trigger, a limited panel of foods may be tested. An avoidance diet is only indicated in patients clearly identified as food allergic by an appropriate diagnostic food challenge, and after adequately informing the family of the limited benefits, and possible harms of an elimination diet.     

Atopic dermatitis: clinical relevance of food hypersensitivity reactions

Forty-six patients with atopic dermatitis ranging from mild to severe were evaluated for food hypersensitivity with double-blind placebo-controlled food challenges. Twenty-eight (61%) patients had a positive prick skin reaction to one of the foods tested. Sixty-five food challenges were performed; 27 (42%) were interpreted as positive in 15 (33%) patients. Egg, milk, and peanut accounted for 78% of the positive reactions. As in previous studies, patients developed skin (96%), respiratory (52%), or gastrointestinal (30%) symptoms during the challenge. These studies indicate that children who have atopic dermatitis unresponsive to routine therapy or who continue to need daily treatment after several months would benefit from evaluation for food hypersensitivity.     

Spontaneous release of histamine from basophils in children with atopic dermatitis

Spontaneous histamine release from basophils was evaluated in children with atopic dermatitis and in healthy controls. Patients were divided into 2 groups, one with specific IgE antibodies for food allergens (Group 1) and one without specific reaginic antibodies (Group 2). Group 1 showed significantly higher histamine release (median 7.25%) than Group 2 (median 4.2%) and healthy controls (median 2.05%). Histamine release was also significantly greater in Group 2 patients compared with healthy controls (p < 0.005). Group 1 was studied again after an exclusion diet which resulted in an improvement of symptoms and a significant reduction (p < 0.001) of histamine release. Children with atopic dermatitis both with and without IgE antibodies for food allergens present a degree of "basophil hyperreactivity" which decreases after an appropriate exclusion diet in children with associated food allergy.     

Food allergy: When and how to perform oral food challenges

In many situations, the diagnosis of food allergy rests simply upon a history of an acute onset of typical symptoms, such as hives and wheezing, following the isolated ingestion of a suspected food, with confirmatory laboratory studies of positive prick skin tests or RASTs. However, the diagnosis is more complicated when multiple foods are implicated or when chronic diseases, such as asthma or atopic dermatitis, are evaluated. The diagnosis of food allergy and identification of the particular foods responsible is also more difficult when reactions are not mediated by IgE antibody, as is the case with a number of gastrointestinal food allergies. In these latter circumstances, well‐devised elimination diets followed by physician‐supervised oral food challenges are critical in the identification and proper treatment of these disorders. Since childhood food allergies to common allergenic foods such as milk, egg, wheat and soy are usually outgrown, oral food challenges are also an integral part of the long‐term management of these children.     

Allergenicity of Common Foods Restricted in Respiratory Allergy

Although hypersensitivity to foods is often linked to exacerbations of symptoms of respiratory allergy, no such information is available regarding the foods traditionally considered to play a probable etiological role in respiratory allergy in India, which are in fact quite different from the ones implicated in the West. The present study was undertaken to investigate whether the practice of withholding certain common foods by parents and practitioners of indigenous systems of medicine (i.e. Ayurvedic and Unani systems of medicine) in children suffering from respiratory allergy had any scientific basis or explanation as judged by modern techniques of investigation. Skin prick tests were performed on 64 children with symptoms pertaining to respiratory allergy (32 each in study and control group) using crude antigenic food extracts. Oral food challenges were administered to children to confirm or rule out allergenicity of food (s) incriminated on the basis of the clinical history and/or a positive skin test. Parental history of food restriction alone, in absence of positive skin prick test was of little value in predicting a positive response to the food challenges (1 challenge positive out of 77 based on food restriction: 1.29%). Only 27.02% and 18.75% of positive skin tests were found to be clinically significant in study and control groups respectively. Traditionally, food beliefs were upheld in only 12.5% children for immediate onset clinical reactions (with 5.31% of the foods restricted in their diet) and 9.37% children for delayed onset clinical reactions (with 3.19% of the foods restricted in their diet). The present study shows that even though food restriction is a common practice in patients with respiratory allergy in India, objective documentation of Type I reactions due to these foods cannot be obtained in a majority of such children.     

Food allergy and atopic dermatitis in infancy: an epidemiologic study

Atopic dermatitis is common in infancy. The role of food allergy in atopic dermatitis of infancy is unclear. We examined the relationship between atopic dermatitis and immunoglobulin E (IgE)-mediated food allergy in infancy. A birth cohort of 620 infants with a family history of eczema, asthma, hayfever or immediate food allergy in a parent or sibling: 487 children had complete data including skin prick tests (SPTs) to evaluate IgE-mediated food allergy to cow milk, egg and peanut. Participants were grouped as no atopic dermatitis (Gp 0) or in quartiles of increasing severity of atopic dermatitis (Gps 1-4) quantified by days of topical steroid use as reported monthly. Adverse reactions to foods were recorded. The cumulative prevalence of atopic dermatitis was 28.9% to 12 months (10.3% of the cohort of moderate severity). As atopic dermatitis severity increased so did the prevalence of IgE-mediated food allergy (Gp 0, 40/346 vs. Gp 1, 6/36 vs. Gp 2, 8/35 vs. Gp 3, 12/35 vs. Gp 4, 24/35; chi(2) = 76; p < 10(-6)), and the frequency of reported adverse food allergy reactions (Gp 0, 43/346 vs. Gp 1, 4/36 vs. Gp 2, 8/35, vs. Gp 3, 5/35, vs. Gp 4, 13/35; chi(2) = 17; p = 0.002). The relative risk of an infant with atopic dermatitis having IgE-mediated food allergy is 5.9 for the most severely affected group. Atopic dermatitis is common in infancy. There is a strong association between IgE-mediated food allergy and atopic dermatitis in this age group.     

The prevalence of allergic diseases in an unselected group of 6-year-old children. The DARC birth cohort study

This study determines the prevalence of atopic dermatitis, asthma, rhinoconjunctivitis, food hypersensitivity and urticaria and the frequency of sensitization in children with and without clinical allergic disease. In an ongoing prospective non-interventional birth cohort study of 562 unselected children, 404 children were subjected to interview, clinical examination, lung function measurements and allergy testing at 6 yr of age. Sensitization measured by skin prick test (SPT) and specific immunoglobulin E (S-IgE) was determined for 24 different allergens. The 1-yr period prevalence of atopic dermatitis, asthma and rhinoconjunctivitis was 14.4%, 6.2% and 13.6%. 25.7% of the children suffered from at least one of the three diseases. The frequency of sensitization in children with no disease (controls), any allergic disease, atopic dermatitis, asthma and rhinoconjunctivitis was 17%, 45%, 47%, 56% and 55% (defined as SPT ≥3 mm and/or S-IgE ≥0.35 kU/l for at least one allergen). Symptoms were linked to sensitization for 44% in the asthma group and 42% in the rhinoconjunctivitis group, whereas sensitization could not be linked to worsening of the eczema in any cases of atopic dermatitis. Overlap between the three diseases was significantly more frequent in sensitized children than in non-sensitized (19/46 = 41% vs. 9/58 = 16%, p = 0.004). The prevalence of food hypersensitivity and urticaria was 1.2% and 5.4% respectively. In unselected 6 yr old children, approximately half of the children with atopic dermatitis, asthma or rhinoconjunctivitis are IgE-sensitized. Sensitization tends to link these diseases to each other.     

Enhanced IL-4 but normal interferon-gamma production in children with isolated IgE mediated food hypersensitivity

Atopic disorders such as atopic dermatitis and asthma have been characterised by an imbalance in interferon-gamma (INF-γ) and IL-4. Whether similar imbalances are found in atopic disorders with different clinical manifestations, such as IgE mediated immediate food hypersensitivity, is not clear. We have examined the in vitro production of INF-γ and IL-4 in peripheral blood mononuclear cells (PBMC) following phytohaemagglutinin stimulation from children with isolated immediate IgE mediated food hypersensitivity (egg, milk, "nut"), children with moderate and severe atopic dermatitis, and normal children. Children with immediate food reactions were excluded if they had a history or evidence of atopic dermatitis or asthma. PBMC from children with IgE mediated food hypersensitivity produced significantly more IL-4 (p = 0.013) but equivalent INF-γ (p=0.26) compared to PBMC from control children. In contrast, PBMC from children with atopic dermatitis produced significantly less INF-γ (p < 0.001) and more IL-4 (p < 0.008) than PBMC from normal children. In addition, there was no difference in IL-4 (p = 0.74) but significantly less INF-γ (p < 0.001) produced by PBMC from the children with atopic dermatitis than food hypersensitivity. We demonstrate that children with IgE mediated food hypersensitivity and no other manifestation of atopic disease have enhanced IL-4 production without the defect in INF-γ production observed in childhood AD and asthma. We postulate that isolated IL-4 enhancement promotes the development of IgE mediated hypersensitivity disorders such as food allergy, whilst the combination of defective INF-γ and enhanced IL-4 production promotes inflammatory atopic disorders such as AD and asthma.     

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.     

"Expert Consensus on Diagnosis and Management of Food Allergy in Children with Atopic Dermatitis": explanation and elaboration of clinical manifestations and diagnosis北大核心CSCD

为规范儿童特应性皮炎相关食物过敏的诊断和管理,中华医学会皮肤性病学分会儿童学组、中华医学会儿科学分会皮肤性病学组、中国医师协会皮肤科医师分会儿童皮肤病专业委员会共同组织国内专家制定了《儿童特应性皮炎相关食物过敏诊断与管理专家共识》,该共识对儿童特应性皮炎相关食物过敏的临床表现、诊断及管理等方面进行了阐述。现主要就儿童特应性皮炎相关食物过敏临床表现及诊断方面进行详细解读,以便临床工作者精准识别儿童特应性皮炎相关的食物过敏,选择合适的诊断方法辅助诊断,以免因误诊而过度避食、因漏诊而延误患儿病情。     

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.     

Presentation of atopic disease in a large cohort of pediatric liver transplant recipients

Atopic disease occurs in solid organ transplant recipients with an increasingly recognized frequency. The time course for the development of these atopic diseases in liver transplantation has not been described. The objective was to characterize the atopic manifestations of children receiving chronic immunosuppression after orthotopic liver transplantation (OLT). Chart review and follow-up questionnaire were utilized for 176 OLT pediatric recipients at a single institution for manifestations of allergic disease. Atopic disease was present in 25 (14.2%) patients. Median age at transplant was 16 months with a median follow-up of 63 months. Food allergy and non-food related atopic symptoms presented at a median of 11.5 (IQR, 6-28) and 19 (IQR, 5-41) months post-transplantation, respectively. The median age at transplant of the non-atopic children was 72 months, higher than patients with atopy (p < 0.001). Food allergy and atopic skin disease symptoms were present in 40% and 56% of cases, respectively. Asthma, allergic rhinitis, or both were found in 66% of cases. The onset of symptoms of food allergy and eczema (median, 12 months post-transplantation) preceded symptoms of allergic rhinitis and asthma. (median of 27 and 30 months post-transplantation, respectively). Atopy occurs in ～14% of pediatric liver transplant recipients, with manifestations including food allergy, eczema, allergic rhinitis, and asthma.     

Latex allergy in children]

The aim of our study was to determine the prevalence of latex allergy and the clinical features of children with latex allergy. PATIENTS AND METHODS: We prospectively investigated 243 children consulting in our allergy out-patients unit during 1 year. Parents answered a questionnaire, and children underwent skin prick tests with common allergens and latex. Latex-specific serum immunoglobulin E was determined by CAP test in children with latex sensitization. The results were compared in children with and without latex allergy. RESULTS: The prevalence of latex allergy was 1.3%. A family history of atopy (75%) and a personal history of previous surgery was associated with latex allergy (P < 0.0001). In children with latex allergy, the frequency of sensitization to inhaled and food allergens, atopic dermatitis, rhinitis and conjunctivitis was higher than in children without latex allergy (P < 0.05). Avocado allergy was the food allergy most commonly associated with clinical symptoms. Balloon was the most common latex product causing symptoms (60%). CONCLUSIONS: Due to its potential severe consequences, latex allergy should be investigated in children who had undergone multiple surgical procedures and in the children with pollen-food allergy syndrome. Avoidance of latex is an important preventive measure.     

Egg allergy

Egg is one of the most important allergen in childhood feeding. The pathogenic mechanism in egg allergy is immediate, type I, IgE-mediated hypersensitivity, although other mechanisms are possible. The aim of this review is to point out that diagnosis of egg protein allergy is mainly clinical and double-blind placebo-controlled food challenge is nowadays the gold standard. Although reference values for prick test and sIgE have been proposed, which can foretell symptoms in groups of egg sensitive children, these values are not so accurate for a single diagnosis, since they mainly refer to children with atopic dermatitis, and to specific ranges of age. Children with atopic dermatitis can show allergy at the first egg ingestion, as for cow milk allergy, because the sensitization may happen in utero or through breast milk. The only available therapy in case of egg allergy is the complete removal of hen egg from the child's diet, yet considering cross-reaction with other birds' eggs, while cross- reaction with poultry and/or other birds' meat has been signalled only in 5% of cases. From this review it is clear how egg allergic children can be vaccinated against measles-mumps rubella.     

How Common Is Food Allergy?

ABSTRACT. In the absence of accurate epidemiological data, it is recognised that significant food allergy will affect a proportion of the atopic group, which itself comprises about 10% of the childhood population. Some food allergic children will also be found among non-atopics and many allergic children will lose their allergy as they grow through infancy. Early feeding choices probably have less effect on the occurrence of allergy than was previously thought. Some children may also react adversely but not immunologically to other natural and added substances in food, although this is not a common problem in weaning diets. In typical food allergy and hypersensitivity, and in more subjective areas concerned with behavioural variations more basic and epidemiological research is needed.     

Diagnostik und Therapie der Nahrungsmittelallergie im Kindesalter

Food allergy is a common problem in infants and children, prevalences of 2–5% being reported. While immediate-type allergic reactions to foods can be diagnosed quite easily, the diagnosis of late-phase reactions, e.g. in atopic dermatitis, is often challenging. The aim of this review article is to present a practical procedure for diagnosing food allergy in infants and children. Once the classic diagnostic procedures, such as history, skin prick tests, atopy patch test, and determination of specific IgE in the serum have been exhausted, double-blind, placebo-controlled food challenges are seen as the gold standard. After the subject has been fed an oligo-allergenic diet, suspected foods or placebo are given in a titrated manner until a clear clinical reaction is seen or the highest dose is reached. An observation period of 48 h is required in each phase in the case of atopic dermatitis. Constant monitoring of clinical reactions is mandatory. Dietetic recommendations are given, and once these have been followed for 12 months the position should be reassessed. The effort involved in such a procedure is justified, since it can help to avoid clinically relevant food allergens in some cases and in others can prevent children from being exposed unnecessarily to diets that may be harmful to them. Therapeutic options in the case of cow's milk allergy include feeding with extensively hydrolysed formulae or, when intolerance to these is observed, with amino acid formulae, on both of which children generally thrive.     

Food allergy and atopic dermatitis in low birthweight infants during early childhood

The prevalence rates of food allergy and atopic dermatitis in low birthweight infants were evaluated. In Fukuoka City, Japan, between July 1994 and September 1997, sufficient information including birthweight, gestational age, sex, feeding method and a history of food allergy was obtained from questionnaires at the well-baby check-ups of 21766 infants (18 mo of age) and 4378 children (3 y of age). All the children were examined by pediatricians with regard to the existence of atopic dermatitis. The prevalence rate (8.1%) of food allergy in infants with low birthweight (<2,500 g) was significantly lower than that (11.2%) in infants with normal birthweight (> or = 2,500 g) at 18 mo of age (p = 0.0002). Atopic dermatitis was also observed at a lower prevalence rate (1.2%) in infants with low birthweight than in those with normal birthweight (2.3%) at the same age (p = 0.0041). However, this significance was lost at 3 y of age. Other characteristics including male sex and breast-feeding showed independent risks for the development of food allergy and atopic dermatitis at both ages. CONCLUSION: This study found that low birthweight was significantly associated with a lower risk of both food allergy and atopic dermatitis at 18 mo of age.