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。     

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.     

Predictive features for persistence of atopic dermatitis in children

Allergen exposure plays an important role in atopic dermatitis (AD). Because immunological mechanisms underlying asthma and AD have great similarities, we evaluated whether features such as allergen sensitization, immune response, disease severity and duration or allergen exposure could be considered predictive for AD persistence. Seventy-one AD children (age range 14–158 months) were enrolled and followed for 3 consecutive years for AD severity using the SCORAD index (SI). At enrollment, reactivity to inhalant and food allergens using the skin prick test (SPT) and house dust mite (HDM) atopy patch test (APT), and HDM allergens in house dust were evaluated. After 3 years, 38 children outgrew their AD (AD^– group), while in 33 AD persisted (AD⁺ group). At enrollment, AD⁺ children had a higher SI, higher rate of positivity to SPT and APT for mites (p = 0.001), and higher environmental exposure to HDM allergens (p = 0.035). The AD⁺ children developed more respiratory symptoms in comparison to AD^– children (p < 0.001). None of the AD^– children presented APT positivity. In our study population, positivity of SPT and APT for HDM, environmental allergen exposure levels and severity of the disease at enrollment presented a significant predictive power towards AD persistence. Subjects with positive skin reactivity to HDM should be considered at risk of AD persistence and of possible development of allergic respiratory disorders.     

Behavioral characteristics in 3- to 12-month-old infant with atopic dermatitis: a case–control study

There have been reports that refer to the personality of the patients with atopic dermatitis (AD) especially adult patients but there are few studies regarding the behavioral characteristics in AD infants. The aim of this study was to compare behavioral characteristics of 30 AD infants (3-12 months old) with 40 controls. The infants with the definite diagnosis of AD (according to Hanifin and Rajka criteria) referring to children medical center were included in this study. For assessing behavioral characteristics we used revised version of Infant Behavior Questionnaire for measuring 11 scales of behavioral characteristics (Fear, Perceptual Sensitivity, Distress to Limitations, Sadness, High Pleasure, Low pleasure, Approach, Rate of Recovery from Distress, Soothability, Smiling and Laugher, and Duration of Orienting). Questionnaires were filled out by the physicians with the cooperation of the parents. The AD group showed significantly higher scores in Perceptual Sensitivity, Soothability, and High Pleasure compared with control group (p = 0.000). In other characteristics no significant difference were noticed between atopic and non-patients. For eight characteristics, scores of atopic infants were similar healthy infants, but they tend to show more pleasure when subjected to an intense, novel or incongruity stimuli compared with healthy infants. Theoretically, higher scores in Perceptual Sensitivity, Soothability, and High Pleasure are concordant with the pervious studies about adrenomedullary system over activity.     

Prenatal exposure to house dust mite allergen (Der p 1), cord blood T cell phenotype and cytokine production and atopic dermatitis during the first year of life

This study investigated the influence of prenatal exposure to house dust mite (HDM, D. pteronyssinus) on interleukin (IL)-2, interferon-gamma (IFN-gamma) and IL-4 producing CD4(+) and CD8(+) T lymphocytes in cord blood as well as on the development of sensitization and occurrence of atopic dermatitis (AD) as the first symptom of allergy during the first year of life. Dust samples (n = 22) were collected by vacuum cleaning the maternal mattress during early to mid-pregnancy. In these samples, the amount of the major HDM antigen (Der p 1) was assessed by a sensitive enzyme-linked immunosorbent assay technique (detection limit 0.004 microg/g dust). Flow cytometry was used to determine cord blood lymphocyte subtypes and to quantify the intracellular amounts of IL-2, IFN-gamma and IL-4 produced by cord blood CD4(+) helper and CD8(+) cytotoxic T lymphocytes, both spontaneously and after stimulation with phorbol-12-mirystate-13-acetate and ionomycin. Children were followed for 1 yr for the presence of symptoms associated with allergy. In addition, at the age of 1 yr specific IgE to different classical inhalant and food allergens was measured. Higher prenatal exposure to Der p 1 (>0.2 microg/g dust) was associated with a significant lower percentage of IFN-gamma producing stimulated CD4(+) T lymphocytes, compared with lower prenatal Der p 1 exposure (p = 0.03). The presence of AD during the first year of life (n = 9) was associated with an increased number of naive CD4(+) CD45RA(+) lymphocytes (p = 0.03), with an increased spontaneous IL-4 production by CD8(+) lymphocytes (p = 0.04) and with a decreased percentage of IFN-gamma producing stimulated CD4(+) lymphocytes (p = 0.04). Furthermore, exposure to HDM during pregnancy tended to be higher in mothers of children with AD during the first year of life when compared with those without AD (p = 0.08). This study shows that the level of prenatal exposure to Der p 1 influences the immune profile of cord blood T lymphocytes and the clinical outcome in early life. Therefore, the prenatal environment must be regarded as a possible early risk factors for allergic diseases in children.     

The use of mutually exclusive categories for atopic sensitization: A contrasting effect for family size on house dust mite sensitization compared with ryegrass sensitization

Our aim was to examine the relative importance of family size on sensitization to two different allergens: ryegrass and house dust mite (HDM), using a mutually exclusive classification for allergen-specific sensitization. An 8-year follow-up birth cohort study of children born between 1988–89 was conducted. The follow-up sample consisted of 498 children residing in Northern Tasmania in 1997 (84% of eligible). Outcome measures included skin prick test (SPT) reaction to nine aeroallergens and parental questionnaire. Family size was defined as sibling number in 1997. Children with a positive SPT to either Der p or Der f house dust mite but not ryegrass were classified as HDM-exclusive (n = 84). Children with a positive SPT to ryegrass but not HDM were classified as ryegrass-exclusive (n = 43). Family size was associated with reduced ryegrass-exclusive sensitization [AOR 0.57 (0.39, 0.84) per increase in sibling number] but not HDM-exclusive sensitization [AOR 0.97 (0.77,1.23)]. The difference in the family size effect on these sensitization outcomes was significant (p = 0.02). Similarly, family size tended to be associated with reduced asthma among ryegrass-exclusive sensitized children [AOR 0.45 (0.18,1.12)] but not HDM-exclusive sensitized children [(AOR 1.46(0.80–2.65)]. Large family size was strongly associated with reduced sensitization for ryegrass allergens but not HDM allergens using mutually exclusive sensitization categories. If this difference is confirmed in other studies, the contrasting effect of family size may reflect differences between these allergens with regard to level or timing of early life exposure, differences in allergen -specific potentiation for sensitization or unidentified confounding. The use of mutually exclusive categories for allergen sensitization will assist future work on child atopic disease.     

Sensitization to turnip rape and oilseed rape in children with atopic dermatitis: a case-control study

Turnip rape and oilseed rape 2S albumins are new allergens in children with atopic dermatitis suspected for food allergy. We recently found that 11% (206/1887) of these children had a positive skin prick test to seeds of oilseed rape ( Brassica napus ) and/or turnip rape ( Brassica rapa ). In the present case-control study we examined how the children with atopic dermatitis sensitized to turnip rape and oilseed rape had been breast-fed and whether they had some common sensitization pattern to certain foods or pollens. A total of 64 children with atopic dermatitis and a positive skin prick test to turnip rape and/or oilseed rape (≥5 mm) were examined. Sixty-four age- and sex-matched children with atopic dermatitis but negative skin prick tests to turnip rape and oilseed rape served as case controls. The turnip rape and/or oilseed rape sensitized children with atopic dermatitis had significantly more often positive skin prick tests reactions and IgE antibodies to various foods (cow's milk, egg, wheat, mustard; p < 0.01) and pollens (birch, timothy, mugwort; p < 0.01) than the control children. They had been exclusively breast-fed for a longer period (median 4 months; p < 0.05) and had more often associated asthma (36%) and allergic rhinitis (44%). Children with atopic dermatitis sensitized to oilseed rape and turnip rape had high frequency of associated sensitizations to all foods and pollens tested showing that oilseed plant sensitization affects especially atopic children who have been sensitized to multiple allergens.     

Hospital admission with neonatal sepsis and development of atopic disease: Is there a link?

The role of suspected or confirmed neonatal sepsis in modifying the risk of atopic disease during childhood was assessed. Children with early-onset neonatal sepsis were identified from a cohort of neonates, hospitalized between 1990 and 1995. Of 196 individuals, 140 were recruited (71.4%). Pre- and postnatal history was ascertained from neonatal medical records. Based on clinical symptoms and a positive blood culture or at least three of initially defined laboratory or bacteriological criteria, they were stratified in either confirmed neonatal sepsis (CS) or suspected sepsis (SS) group. A control group (C) comprised children who were never hospitalized during infancy (n = 696). Primary end-point was the development of atopic dermatitis, bronchial asthma or allergic rhinitis during childhood (mean age 8.4 yr, range 5.7-12.4). CS and SS children had a higher prevalence of atopic dermatitis (CS 15.7%, SS 21.4%) compared with controls (C 5.2%, p < 0.001). Similarly, children with SS (7.1%), but not with CS (4.3%) had significantly more often a doctor's diagnosis of bronchial asthma compared to controls (1.9%, p = 0.02). No difference in the prevalence of allergic rhinitis was observed (CS 4.3%, SS 10%, C 8.3%). After adjusting for parental history of atopic disease and demographic factors, no significant difference for the risk to develop atopic dermatitis, asthma or allergic rhinitis among the groups was calculated in children with normal birth weight (>2500 g). Our data failed to show a possible link between hospital admission with SS and development of atopic disease.     

Montelukast in the treatment of children with moderate-to-severe atopic dermatitis:A pilot study

The primary action of leukotrienes includes contraction of human airway muscle, chemotaxis, and increased vascular permeability, with secondary effects of inhibiting allergen-induced early and late responses. Although there is limited available information and research regarding leukotrienes in atopic dermatitis (AD), there is evidence to support their role in the pathogenesis of the disease. We conducted a pilot study to test the efficacy of montelukast, a cysteinyl-leukotriene-1 receptor antagonist, in 15 patients (6–16 years of age) with moderate-to-severe AD, using a randomized double-blind placebo-controlled crossover study. These patients had chronic moderate-to-severe AD, despite being on conventional therapy. They were randomized either to placebo for 4 weeks and then the study drug for 4 weeks, or vice versa. There was a 2-week run-in period for all participants before commencement of the study, and a 2-week washout before crossover. At enrollment and on each follow-up visit, every patient was assessed by a single observer and objectively scored for disease extent and severity. A subjective score was given for the impact of eczema on daily living. There was statistical improvement in patents on active treatment compared with placebo in the severity of AD (p < 0.05). Our findings suggest that leukotriene receptor antagonist as an adjunct treatment has an anti-inflammatory effect on moderate-to-severe AD. A larger trial is needed to ascertain its efficacy fully.