Does the severity of atopic dermatitis correlate with serum IgE levels?

Recent studies suggest an association between atopic phenotypes and serum IgE levels. In contrast to asthma, this association has not been proven for atopic dermatitis. For 345 children (mean age 2.9 years), we investigated a correlation of the severity of eczema (defined by SCORAD score) and serum IgE levels. Additionally, the data was analyzed for differences between children with high and low SCORAD quartile. Parameters such as genetic background, the prevalence of other atopic phenotypes such as bronchial asthma, allergic rhinoconjunctivitis, and allergic sensitization were recorded. Our results indicate a significant correlation between SCORAD and serum IgE levels (R = 0.31, p < 0.001), but the standard deviation was large. Children with atopic dermatitis showed a high prevalence of sensitization to foods independent of the IgE levels; children with high SCORAD levels showed a sensitization to aeroallergens significantly more often (p < 0.02). No differences were found in prevalences of atopic family background, or a number of additional atopic symptoms such as asthma and allergic rhinoconjunctivitis. These results suggest that serum IgE levels seem to correlate with the degree of eczema. Children with severe atopic dermatitis and high IgE levels are at risk for sensitization to food allergens and aeroallergens.     

The association of allergic symptoms with sensitization to inhalant allergens in childhood

Although it is generally agreed that sensitization is an important risk factor for allergic diseases, the extent to which sensitization accounts for allergic symptoms in children is controversial. As part of the Aalst Allergy Study, this cross‐sectional study investigated the prevalence of allergic symptoms and their association with sensitization in an unselected population of Flemish children aged 3.4–14.8 yr. Skin prick testing with the most common aeroallergens was performed and allergic symptoms were documented by a parental questionnaire. In the children older than 6 yr, a significant association of current wheezing, current dyspnea, airway hyperreactivity, rhinoconjunctivitis, and current eczema with sensitization was found, while in the pre‐school children these associations were less pronounced. The association with sensitization was strongest for rhinoconjunctivitis and current respiratory symptoms – the association was less striking for children with current eczema. The impact of a positive family history of allergy on the association with sensitization was more important for eczema than for the other analyzed allergic symptoms. Persistent and late‐onset wheezers were significantly more likely than non‐wheezers and transient early wheezers to be associated with sensitization and a personal history of rhinoconjunctivitis. Late‐onset wheezing was associated with a positive family history of allergy, while transient early wheezing was associated with day‐care attendance. An association with eczema was found for all three childhood wheezing phenotypes. The association of allergic symptoms with sensitization is significant in the older but less pronounced in pre‐school children and is more pronounced for current allergic symptoms. Diagnosis and disease definition of allergy symptoms remains difficult at pre‐school age. The influence of a positive family history of allergy on the association of the respective allergic symptoms with sensitization was most important for eczema. Our data confirm the atopic characteristics of the different wheeze phenotypes.     

The association between early sensitization patterns and subsequent allergic disease. The DARC birth cohort study

Prevention of allergic diseases depends on early identification of clinical markers preceding such disorders. This study describes the natural course of sensitization as measured by skin prick test (SPT) and specific immunoglobulin E (S‐IgE) and analyses the association between early sensitization patterns and subsequent allergic disease at 6 yr of age. In an ongoing population‐based birth cohort study of 562 children, follow‐up visits were performed at 0, 3, 6, 9, 12, 18, 36, and 72 months. Visits included an interview, physical examination, SPTs, and S‐IgE measurements for 12 food and inhalant allergens. The frequency of S‐IgE sensitization to ≥1 inhalant allergen was constant from 0 to 6 months (9–10%), decreased at 12–18 months before increasing from 36 months onwards. S‐IgE sensitization to at least one food allergen remained constant from 0 to 6 yr. SPT sensitization to food and inhalant allergens appeared from 3 and 12 months, respectively. Early food sensitization (S‐IgE) between 3 and 18 months was found to be significantly (p < 0.05) associated with atopic dermatitis (OR: 4.0 [1.6–9.9]) and asthma (OR 4.0 [1.1–12.5]) at the age of 6 yr. Children with atopic dermatitis, asthma, or rhinoconjunctivitis, and sensitization at 6 yr, were sensitized to food allergens to a large extent (53%, 42%, and 47%, respectively) already at 6 months. Early inhalant sensitization (S‐IgE) did not increase the risk of later allergic disease. Early atopic dermatitis (0–18 months) was also highly associated with subsequent allergic disease. Children with early food sensitization and/or atopic dermatitis would be a proper target group for future interventional studies.     

IL13 variants are associated with total serum IgE and early sensitization to food allergens in children with atopic dermatitis

Increased total and specific serum immunoglobulin E (IgE) levels are common characteristics of atopic diseases and their basal production is proposed to be under strong genetic control. Interleukin 13 (IL13) variants have been consistently associated with total serum IgE levels in white populations with a strongest association in non‐atopics. The aim of this study was to test the IL13 p.R130Q and c.1‐1111C>T variants in children with atopic dermatitis (AD) for associations with total serum IgE and early sensitization to common food and inhalant allergens and with asthma. We included 453 children with AD [participants of the Early Treatment of the Atopic Child (ETAC) study] that were followed from the age of 12–24 months for 3 yr. Total and specific IgE were determined at four time points. We genotyped the IL13 p.R130Q and c.1‐1111C>T variants by melting curve analysis. In children up to 4 yr of age, the 130Q allele was related to slightly higher total IgE levels compared to heterozygotes and 130R homozygotes. More importantly, both IL13 variants were significantly associated with sensitization to food allergens, with most significant results for sensitization to egg (p = 0.0001). Although early sensitization to hen’s egg represents a strong risk factor for subsequent sensitization to inhalant allergens and asthma, the investigated IL13 variants were not associated with these phenotypes at the age of 48–60 months. In summary IL13 variants contribute to elevated levels of total serum IgE in young atopic children and are strongly associated with sensitization to food allergens, particularly to hen’s egg. These findings suggest that IL13 variants play a major role not only in non‐cognate but also in allergen specific IgE synthesis.     

The association of atopic dermatitis in infancy with immunoglobulin E food sensitization

OBJECTIVE: To prospectively investigate the association of high levels of immunoglobulin E (IgE) sensitization to foods and the presence of atopic dermatitis (judged by reported topical steroid use during the first 16 months of life) in a birth cohort of 620 Australian children "at risk" of allergic disease because of family history. RESULTS: A total of 559 of the children in the cohort were fully evaluated, and the cumulative prevalence of atopic dermatitis was 24%. More children in the cohort who had atopic dermatitis had strongly positive skin test results (> or = 4+, histamine equivalent units, > or = approximately 6-mm wheal), consistent with IgE food sensitization to either cow's milk, egg, or peanut at 6 months (22% vs 5%, chi(2) = 35; P < 10(-6)) and at 12 months (36% vs 11%, chi(2) = 41; P < 10(-6)) than those without atopic dermatitis. The calculated attributable risk percent for IgE food sensitization as a cause of atopic dermatitis was 65% and 64% at these times. In a separate group of infants with severe atopic dermatitis, the equivalent rates of IgE food sensitization at 6 months was 83% and at 12 months, 65%. CONCLUSION: IgE food sensitization is a major risk factor for the presence of atopic dermatitis in infancy.     

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.     

No association between tuberculin skin test and atopy in a bacillus Calmette-Guérin vaccinated birth cohort

Previously, an inverse association was suggested between mycobacterial infection and atopy. We aimed to determine the association between tuberculin skin test (TST) and allergic manifestations in a birth cohort where all infants were vaccinated with bacillus Calmette-Guérin (BCG) at birth. Newborns were enrolled randomly and prospectively followed up for a period of 5 yr. Information on family history and environmental factors was obtained at birth, International Study of Asthma and Allergies in Childhood asthma questionnaire, physical examination, skin prick test to common inhalant and food allergens and TST were performed at 2 and 5 yr of age. Positive TST reactivity was defined as an induration of ≥10 mm. A total of 399 newborns were enrolled, 293 and 125 were available for a followup visit at 2 and 5 yr of age respectively. The prevalence of ever asthma, rhinitis and allergen sensitization tended to increase while eczema decreased with time. No significant association was found between TST reactivity and ever and current wheeze, doctor diagnosed asthma or atopic sensitization both at 2 and 5 yr of age. This prospectively designed birth cohort study did not confirm the previously suggested inverse correlation between TST reactivity and atopic sensitization or any allergic manifestations in Turkish children vaccinated with BCG at birth.     

Filaggrin gene variants and atopic diseases in early childhood assessed longitudinally from birth

Bønnelykke K, Pipper CB, Tavendale R, Palmer CNA, Bisgaard H. Filaggrin gene variants and atopic diseases in early childhood assessed longitudinally from birth.
Pediatr Allergy Immunol 2010: 21: 954–961.
© 2010 John Wiley & Sons A/S Copenhagen Prospective Study on Asthma in Childhood (COPSAC) was one of the discovery cohorts of the association between eczema and variants in the filaggrin coding gene (FLG). Here, we study the FLG‐associated risk of asthma symptoms in early life and describe the temporal relationship in the development of the different FLG‐associated atopic outcomes: asthma, sensitization and eczema, assessed longitudinally from birth. A high‐risk cohort of 411 children was assessed in a prospective clinical study from birth to school‐age. Asthma, acute severe asthma exacerbations, sensitization and eczema were diagnosed prospectively by the investigators. FLG variants R501X and Del4 were determined in 382 Caucasians. Filaggrin variants increased risk of developing recurrent wheeze, asthma and asthma exacerbations (hazard ratio 1.82 [1.06–3.12], p = 0.03), which was expressed within the first 1.5 yr of life. Children with filaggrin variants had a marked and persistent increase in acute severe asthma exacerbations from 1 yr of age (incidence ratio 2.40 [1.19–4.81], p = 0.01) and increased risk of asthma by age 5 (odds ratio 2.62 [1.12–6.11], p = 0.03). FLG variants increased the risk of eczema, manifesting fully in the first year of life (point prevalence ratio for age 0–5 was 1.75 [1.29–2.37]; p‐value = 0.0003) contrasting the increased risk of specific sensitization by age 4 (odds ratio 3.52 [1.72–7.25], p = 0.0007) but not age 1.5. This study describes a FLG‐associated pattern of atopic diseases characterized by the early onset of asthma symptoms and eczema and later development of sensitization. The association of filaggrin variants with asthma suggests skin barrier dysfunction as a novel, and potentially modifiable, mechanism driving early childhood asthma.     

Mode of delivery and development of atopic disease during the first 2 years of life

It has been hypothesized that cesarean delivery might have an impact on the development of atopic diseases because of its gut flora modulating properties. In the present study, we analysed the association between cesarean delivery and atopic diseases using data of 2500 infants enrolled in the LISA-Study, a German prospective multicenter birth cohort study. Data on symptoms and physician-diagnosed atopic diseases were gathered by questionnaires shortly after birth and at infant's age 6, 12, 18, and 24 months. In addition, sensitization to common food and inhalant allergens was assessed by measuring specific immunoglobulin E (IgE) using the CAP-RAST FEIA method at the age of 2 yr. Confounder-adjusted odds ratios (aOR) with 95% confidence intervals (CI) were calculated by multiple logistic regression. We found a positive association between cesarean delivery and occurrence of at least one episode of wheezing [aOR 1.31 (95% CI 1.02–1.68)] and of recurrent wheezing [1.41 (1.02–1.96)] during the first 2 yr of life. Furthermore, effect estimates for allergic sensitization defined as at least one specific IgE ≥0.70 kU/l against any allergen [1.48 (0.98–2.24)], against food allergens [1.64 (1.03–2.63)], and against inhalant allergens [1.75 (0.98–3.12)] were increased. Symptoms of atopic dermatitis [1.21 (0.92–1.59)], physician-diagnosed atopic dermatitis [1.04 (0.79–1.39)], and symptoms of allergic rhinoconjunctivitis [1.40 (0.80–2.44)] were only marginally increased in children delivered by cesarean section. In conclusion, our results suggest that cesarean delivery may be an additional risk factor for wheezing and allergic sensitization at least to food allergens up to the age of 2 yr. This should be considered when cesarean section is done for other than medical reasons.     

Determinants of atopic sensitization in Turkish school children: Effects of pre- and post-natal events and maternal atopy

Emergence of new environmental risk factors, and/or loss of protective factors of a traditional lifestyle may explain the increase, or variations in prevalence of allergic diseases. The aim of this study was to delineate the prevalence and spectrum of, and to reveal the causal and/or protective factors for atopic sensitization among a heterogenous cohort of Turkish children, for the first time in our country. The study design adhered to International Study of Asthma and Allergies in Childhood (ISAAC) phase II protocol. A self‐administered parental questionnaire about demographic characteristics and detailed risk factors, and skin‐prick test with 13 allergens were employed in a clustered random sample of 8–11‐yr‐old Turkish school children. Atopy was defined as the presence of at least one positive skin reaction to any allergen tested. The association between a total of 78 risk factors and different aspects of atopy were analyzed in 1144 children with multivariate logistic regression analysis. The overall prevalence of atopy was 20.6%. Most common sensitizations were to grass pollens, Dermatophagoides pteronyssinus and Blatella germanica. Day care attendance, high paternal education level, male gender and maternal asthma were significant risk factors for atopy. Breastfeeding more than 6 months (compared with 0–6 months), maternal smoking during pregnancy and a birth weight under 2500 g were inversely related to (or protective factors for) atopic sensitization. Maternal atopic disease had significant effects on risk factors pattern. In children with a maternal atopy history a low birth weight, day care attendance and maternal smoking during the first year of life independently increased the risk of atopic sensitization. Gender, breastfeeding and paternal education did not show any association with atopy in this group of children. A history of measles and low gestational age were significant protective factors for mite sensitization. This study showed that children of atopic mothers showed a different profile of risk factors associated with atopic sensitization, when compared with other children. Prenatal and early childhood events had important associations with atopic sensitization.     

What lessons can be learned about asthma phenotypes in children from cohort studies?

‘Phenotyping’ asthma by multivariate analyses and more recently by unsupervised analysis has been performed in children cohorts. We describe the key findings that have emerged from these cohorts. It would appear that there are three wheeze phenotypes in children of preschool age: the mild episodic viral wheeze phenotype; the multitrigger atopic wheeze; and, less often encountered, the severe non‐atopic wheeze. Early onset of allergy in asthma (more prevalent in boys) is associated with poor prognosis unlike the severe non‐atopic wheeze phenotype which has a female predominance. The prognosis of the severe non‐atopic wheeze depends on time of onset (early or late) of allergic expression. At school age, the risk of severe asthmatic exacerbations is associated with eosinophil predominant inflammation frequently related to allergic asthma, whereas neutrophil inflammation is associated with moderate‐to‐severe asthma with poorer lung function. Nevertheless, allergic asthma is also a heterogeneous disease with a severe allergic phenotype strongly associated with atopic dermatitis and very high eosinophil‐driven inflammatory markers. Further studies are required to find non‐invasive biological markers in very young children to better define wheezing phenotypes associated with an elevated risk of developing severe asthma with a view to personalizing treatment.     

The relationships among immunoglobulin levels,allergic sensitization,and viral respiratory illnesses in early childhood

Possin ME, Morgan S, DaSilva DF, Tisler C, Pappas TE, Roberg KA, Anderson E, Evans MD, Gangnon R, Lemanske RF, Gern JE. The relationships among immunoglobulin levels, allergic sensitization, and viral respiratory illnesses in early childhood.
Pediatr Allergy Immunol 2010: 21: 990–996.
© 2010 John Wiley & Sons A/S IgE plays an essential role in type I allergy, however, there is less information about the relationship between other immunoglobulins (IgA and IgG) and atopic phenotypes in early childhood. We hypothesized that levels of circulating IgA in early childhood would be inversely related to the number of respiratory infections and the risk of becoming sensitized to allergens. Immunoglobulin levels were analyzed (ELISA) in plasma samples (IgG, IgA), and in nasal secretions (IgA) from children participating in a high‐risk birth cohort study. Samples were available from 264 children at age 2 yr and 257 children at age 4 yr, and results were compared to rates of respiratory illnesses, allergic sensitization, atopic dermatitis (AD), and asthma. Children who were sensitized to allergens had higher rather than lower levels of circulating IgA. A subgroup analysis showed that IgA levels were increased in relationship to foods sensitization (58 vs. 50 mg/dl, p = 0.003) but not aeroallergen sensitization (52 vs. 53 mg/dl, p = 0.11). IgA levels in the plasma correlated with levels of IgE levels (r_s =0.19, p = 0.003). Levels of IgE, but not IgG or IgA, were positively correlated with rates of respiratory illnesses, AD, and the risk of developing asthma. Finally, there were no significant relationships between IgA in nasal secretions and infectious outcomes. In conclusion, low‐normal concentrations of plasma IgA are associated with a reduced prevalence of allergic sensitization in infancy. Further, levels of IgA and IgG in plasma within the range of normal, and IgA in nasal secretions, do not appear to influence the risk of subsequent respiratory illnesses. Further studies to define relationships between IgA and allergic sensitization are likely to provide new insights into the pathogenesis of allergic diseases in infancy.     

Epidemiologic characteristics of rhinitis in Turkish Children: the International Study of Asthma and Allergies in Childhood (ISAAC) phase 2

Rhinitis is a common problem with important comorbidities. In order to search the association between rhinitis, allergic phenotypes and other risk factors in Turkish children, a parental questionnaire about allergic diseases and risk factors, and skin prick test (SPT) with 13 inhalant allergens were performed in a population-based sample of 2774 children aged 9-11 yr. Bronchoprovocation testing with hypertonic saline (HS)and total IgE analysis were limited to a subsample of 350 children. Rhinitis was defined as a problem with sneezing, rhinorrhea, or nasal congestion when the child did not have a viral respiratory infection. The prevalences of ever rhinitis, current (last 12 months) rhinitis (CR), and ever hay fever were 36.3%, 30.6%, and 8.3%, respectively. SPT positivity rate was 20.4% among children with CR. Current wheezing and flexural dermatitis were significantly associated with CR. CR significantly increased the risk of asthma among both atopic and non-atopic subjects [odds ratio (OR), 3.98; 95% CI, 1.81-8.76; and OR, 2.79; 95% CI, 1.82-4.26, respectively]. The association between CR and bronchial hyperreactivity (BHR) was not significant. The multiple logistic regression analysis revealed family atopy (OR=2.25, 95% CI=1.79-2.83, p<0.001), current indoor heating with gas stove (OR=1.78, 95% CI=1.18-2.64, p=0.006) and dampness/molds at home during the first year of life (OR=1.70, 95% CI=1.25-2.31, p=0.001) as significant risk factors for CR. Turkish school children showed a high prevalence of rhinitis with a preponderance of non-atopics. The highly significant association between rhinitis and asthma independent of atopic sensitization emphasize the importance of non-atopic forms of rhinitis.     

Margarine and butter consumption, eczema and allergic sensitization in children. The LISA birth cohort study

It has been hypothesized that margarine intake is associated with allergic diseases. However, the epidemiological evidence in children is limited. The aim of the present study was to assess the relationship between dietary intake of margarine and butter with eczema and allergic sensitization in 2-yr-old children. Data of 2582 children at the age of 2 yr with complete information on exposure to diet and allergic outcome were analyzed in a German prospective birth cohort study (LISA). Margarine and butter intake were estimated from a semiquantitative food frequency questionnaire about general fat use at home combined with questions on the child's spread intake. Multiple logistic regression analysis was applied comparing predominant margarine and predominant butter intake with consumption of both butter and margarine. Predominant margarine intake was positively associated with lifetime prevalence of symptomatic eczema (aOR: 1.71; 95% CI: 1.12-2.61) and doctor-diagnosed eczema (aOR: 2.10; 95% CI: 1.36-3.25) and allergic sensitization against inhalant allergens (aOR: 2.10; 95% CI: 1.01-4.41) at the age of 2 yr. No statistically significant associations were found for butter intake. Stratification for parental history of atopic diseases indicated that children at high risk of atopic diseases have higher effect estimates for margarine intake compared to children without parental history of atopic diseases. Stratification for sex also showed higher effect estimates in boys. Children with predominant margarine consumption had an increased risk for eczema and allergic sensitization, while butter intake was no predictor for allergic diseases. However, we could not determine whether margarine is a causal risk factor or whether other lifestyle factors have influenced this association.     

Association between exposure to pesticides and allergic diseases in children and adolescents: a systematic review with meta-analysis

ObjectiveThe study aimed to conduct a systematic review of the literature to verify the association between exposure to pesticides and allergic diseases (asthma, allergic rhinitis, and atopic dermatitis) in children and adolescents.MethodA systematic review and meta-analysis were performed using the PRISMA method with the question “What is the association between exposure to pesticides and allergic diseases in children (asthma, allergic rhinitis, and atopic dermatitis)?” MEDLINE, EMBASE, SciELO, and Cochrane electronic databases were searched throughout the period in the literature up to September 2020. A total of 1296 studies were found, and 24 were selected.ResultsExposure to pesticides showed a two-fold greater risk of developing or exacerbating asthma in children and adolescents (odds ratio [OR] = 2.14 95% confidence interval [CI] 1.26-3.64, p < 0.01). There was no association between exposure to pesticides and the development of allergic rhinitis (OR = 2.73, 95% CI 0.13-57.8, p = 0.52) and atopic dermatitis (OR = 2.19, 95% CI 0.51-9.36, p = 0.29).ConclusionsExposure to pesticides increases the risk of developing or exacerbating asthma in children and adolescents. There was no evidence of an association between exposure to pesticides and the development of allergic rhinitis and atopic dermatitis in children and adolescents, possibly due to the low number of studies found in this review.     

Allergic sensitization pattern of patients in Brazil

ObjectiveAllergic sensitization is one of the key components for the development of allergies. Polysensitization seems to be related to the persistence and severity of allergic diseases. Furthermore, allergic sensitization has a predictive role in the development of allergies. The aim of this study was to characterize the pattern of sensitization of atopic patients treated at different pediatric allergy referral centers in Brazil.MethodsA nation-wide transversal multicenter study collected data on patients attended in Brazil. Peripheral blood samples were collected to determine the serum levels of allergen-specific IgE. If allergen-specific IgE was higher than 0.1 kUA/L, the following specific components were quantified.ResultsA total of 470 individuals were enrolled in the study. Mite sensitization was the most frequent kind in all participants. A high frequency of sensitization to furry animals and grasses featured in the respiratory allergies. Regarding components, there was a predominance of sensitization to Der p 1 and Der p 2. It has been verified that having a food allergy, atopic dermatitis, or multimorbidity are risk factors for the development of more severe allergic disease.ConclusionStudies on the pattern of allergic sensitization to a specific population offer tools for the more effectual prevention, diagnosis, and treatment of allergic diseases. Sensitization to dust mites house was the most prevalent in the evaluated sample. High rates of sensitization to furry animals also stand out. Patients with food allergy, atopic dermatitis, or multimorbidity appear to be at greater risk for developing more severe allergic diseases.     

Mite component–specific IgE repertoire and phenotypes of allergic disease in childhood: The tropical perspective

To cite this article: Kidon MI, Chin CW, Kang LW, Ching OT, Seng TY, Ning WK, Angus AC, Theng OS, Feng GY, Reginald K, Zhi BX, Shen SH & Tim CF. Mite component–specific IgE repertoire and phenotypes of allergic disease in childhood: The tropical perspective. Pediatr Allergy and Immunol 2011; 22 : 202–210. Sensitization to perennial aeroallergens correlates with the risk of persistent asthma (AS) in children. In tropical Singapore, multiple codominant species of mites abound in the indoor environment, and preferential species‐specific sensitization has been associated with different phenotypes of allergic disease. We investigated the pattern of mite component–specific IgE (mcsIgE) in children with different phenotypes of clinical allergic disease in an environment with multiple mite species exposure. A prospective evaluation of newly diagnosed patients with clinical diagnosis of allergic rhinitis (AR), atopic dermatitis (AD), or AS and sensitization to one or more aeroallergens were performed. Sera were tested for specific IgE against an extensive panel of Dermatophagoides pteronyssinus and Blomia tropicalis allergens. A total of 253 children were included, mean age 7.3 yr, 79% fulfilled criteria for AR, 46% AS, 71% AD, and 31% for all three. Sensitization to one or both mites was observed in 91% of children, 89% were sensitized to D. pteronyssinus, and 70% to B. tropicalis. The most common mite allergens recognized by these atopic children were Der p 1 (64%), Der p 2 (71%), Blo t 5 (45%), Blo t 7 (44%), and Blo t 21 (56%). Specific IgE responses to an increased number of distinct mite allergens correlated with the complexity of the allergic phenotype. In multivariate analysis, an increased risk for the multi‐systemic phenotype (AR + AS + AD) was associated with sensitization to an increased repertoire of mite components (three or more) (OR 4.3, 95% CI 2.1–8.8, p = 0.001) and a positive parental history of AS (OR 2.4, 95% CI 1.2–2.9, p = 0.013). A highly pleiomorphic IgE response to the prevalent indoor mites is associated with the presence of a multi‐systemic allergic phenotype in childhood in a tropical environment.     

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.     

Bimodal skin reactivity to histamine in atopic children in Singapore: influence of specific sensitizations

Histamine skin prick test (SPT) is used as the 'golden standard' for positive control in in vivo immediate type hypersensitivity testing. The skin reactivity to histamine can, however, be modulated by a bevy of extraneous factors. We aimed to define whether histamine skin reactivity in atopic children in Singapore is influenced by age, ethnic origin, gender, environmental exposure or specific sensitization patterns. A retrospective analysis of children, with specific aeroallergen sensitization (as measured by at least one allergen-specific SPT with a wheal size > 3 mm compared with the negative control) from the outpatient speciality clinic of the KK Children's Hospital, during 06/2002-06/2003. A total of 315 patients were included, 235 (75%) were males, 252 (80%) were Chinese, age mean was 7.7 yr (range: 2-15). Patients were referred to the SPT with a diagnosis of one or more of: allergic rhinitis 287 (91%), asthma 112 (36%) or atopic dermatitis 60 (19%). The mean histamine response showed a bimodal distribution, independent of age, ethnic origin, gender or phenotypical expression of allergic disease. Histamine skin reactivity was higher in atopic patients with polysensitization (mean 5.0 mm vs. 2.9 mm in monosensitized patients, p < 0.001), and in patients with mould sensitization (mean 5.1 mm vs. 3.3 mm in patient not sensitized to moulds, p < 0.001). The presence of passive smoking increased the likelihood of a diminished histamine skin response. Histamine skin response data strongly suggested the presence of two heterogeneous subpopulations. Children with polysensitization and mould sensitization were more likely to show a large significant histamine response, whereas children with passive smoke exposure, showed a diminished skin reactivity to histamine.     

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.