Lupin sensitization and clinical allergy in food allergic children in Norway

AIM: The aim of the present pilot study was to investigate to what extent children in Norway sensitized to lupin had clinical lupin allergy, and to compare sensitization to lupin with sensitization to other legumes. METHODS: Thirty-five children with food allergy referred to a national referral hospital were evaluated with skin prick test (SPT) and analysis of serum-specific IgE to lupin, peanut, pea and soy. The children with positive SPTs to lupin were offered oral food challenges with lupin flour. RESULTS: Fifteen children (43%) had positive SPT and 17 children (49%) had serum-specific IgE to lupin. Ten SPT-positive children underwent oral food challenges and one experienced an allergic reaction to lupin flour. This child was one of six challenged children with IgE antibodies to peanut >15 kU(A)/L. There was a strong relationship between positive SPT to lupin flour and positive SPT to soy and between positive SPT to lupin and specific IgE to soy, pea and peanut. CONCLUSIONS: Children with sensitization to lupin are not likely to have a clinical lupin allergy. Avoidance of lupin on the basis of lupin sensitization or peanut allergy would lead to unnecessarily strict diets. Food challenge is currently necessary to diagnose lupin allergy.     

Feeding a soy formula to children with cow's milk allergy: the development of immunoglobulin E-mediated allergy to soy and peanuts.

Peanut allergy has been associated with the intake of soy milk or a soy formula. We studied the development of immunoglobulin E antibodies specific to soy and peanuts and of allergic reactions caused by peanuts, in children with confirmed cow's milk (CM) allergy fed either a soy formula or an extensively hydrolyzed formula (EHF). One hundred and seventy infants with documented CM allergy (CMA) were randomly assigned to receive either a soy formula or an EHF. The children were followed to the age of 4 yr. Peanut-specific immunoglobulin E was measured at the age of 4. A detailed history of the occurrence of allergic reactions caused by peanuts was recorded by the parents. Soy-specific immunoglobulin E antibodies were measured at the time of diagnosis and at the ages of 1, 2 and 4 yr. Immunoglobulin E antibodies to soy (> or =0.35 kU/l) were found in 22 of 70 children fed the soy formula, and in 14 of 70 of the children fed the EHF (p = 0.082). In an open challenge with soy at the age of 4, no immediate reactions were observed. One of 72 children from the soy group had a delayed reaction. immunoglobulin E antibodies to peanuts (> or =0.35 kU/l) were found in 21 of 70 children fed the soy formula and 17 of 69 infants fed the EHF (p = 0.717). The incidence of reported peanut allergy in the soy group was two of 72 (3%) and four of 76 (5%) in the EHF group (p = 0.68). Development of immunoglobulin E-associated allergy to soy and peanuts was rare in our study group of milk allergic children. The use of a soy formula during the first 2 yr of life did not increase the risk of development of peanut-specific immunoglobulin E antibodies or of clinical peanut allergy.     

Prediction of allergy from family history and cord blood IgE levels

Screening of total IgE in 1189 cord blood samples was conducted by Phadebas IgE PRIST in a one-year birth cohort 1983-1984 in Viborg. Denmark. 113 children with cord blood IgE levels ≥ 0.5 kU/l and 138 children chosen at random among those with cord blood IgE levels < 0. 5 kU/l were seen at a follow-up at 5 years of age. Based upon history and physical examination a diagnosis of definite atopy or no atopy was established. Allergy (IgE mediated) was defined as atopic disease combined with increased total IgE levels at 5 years of age. The cumulative prevalence of atopic disease was not influenced by cord blood IgE levels or atopic predisposition. Cord blood IgE levels had a low sensitivity as a predictor of atopic disease. A statistically significant correlation between serum levels of IgE at birth and at 5 years was however found (p < 0.001), and a significantly greater number of children with elevated cord blood IgE levels developed allergic disease before 5 years of age (p < 0.01). A cut-off limit of 0. 3 kU/l was superior to the originally suggested limit of 0. 5 kU/l. A total IgE level > 63 kU/l (geometric mean + 1 SD) at the age of 5 years can be regarded as being an elevated level. A cord blood IgE level ≥ 0.3 kU/l in combination with atopic predisposition was predictive of allergic disease, especially allergic bronchial asthma. With regard to allergic disease, the positive predictive value was 26%, the sensitivity 33% and the rate ratio for development of allergic disease 4. In the case of the most serious atopic disease, allergic bronchial asthma, the positive predictive value was 20%, the sensitivity 87% and the rate ratio 68.     

Combining skin prick, immediate skin application and specific-IgE testing in the diagnosis of peanut allergy in children

Previous studies have suggested various diagnostic cut-offs of allergy tests for the diagnosis of clinical peanut allergy in children. There are few data relating to the use of combinations of these tests in children. We aimed to determine the validity of previously reported diagnostic cut-off levels of peanut allergen skin tests and peanut specific-immunoglobulin (Ig) E, as well as the usefulness of combinations of these, for predicting clinical peanut allergy in our Allergy Clinic. Children attending the Allergy Clinic with a positive peanut skin prick test (SPT; n = 84) were included in the study. Immediate skin application food tests (I-SAFT) using 1 g of peanut butter (positive if any wheals were detected at 15 min), peanut specific-IgE levels and open-label peanut food challenges were performed. Fifty-two of 85 peanut challenges were positive. Skin prick test specificity was 67% at >or=8 mm and 100% at >or=15 mm. The I-SAFT was 82% specific. A peanut specific-IgE level of 0.37 kU/l was 98% sensitive but 33% specific. A level of 10 kU/l was 100% specific. Combinations of a SPT of >or=8 mm with a positive I-SAFT and a peanut specific-IgE >or=0.37 kU/l were 88% specific with a sensitivity of 38%. Using challenge outcomes as the standard, available in vitro and in vivo diagnostic tests for peanut allergy have poor sensitivity and specificity and combining them does not significantly improve their clinical usefulness. Previously described diagnostic cut-off levels do not have general applicability. Allergy practitioners may need to interpret results of allergy tests in the context of their own practices.     

The Prevalence of Allergy and IgE Antibodies to Inhalant Allergens in Swedish School Children

ABSTRACT. Out of 242 children (10 and 14 years of age) in one school-district 221 (93 %) were evaluated for atopy/allergy by a questionnaire, interview, physical examination and determination of S-IgE and IgE-antibodies (RAST) to pollen, animal danders and house dust mite. Eighteen months after the initial examination all 221 children were re-interviewed. All children with previous or current symptoms of atopy/allergy, all children with positive RAST despite a negative history and 20 non-atopic/non-allergic RAST-negative children were tested with a skin prick test (SPT). At the initial examination the cumulative incidence of atopy/allergy was 32.6% and positive RAST was obtained in 40 children (18.1%). At the follow-up the incidence of atopic/allergic symptoms during the last 18 months was 25.8%. The current prevalence of allergy to pollen and danders, assessed by interview only, was 19 % and 9 % respectively while determined by both interview and positive SPT 15 % and 5 % respectively. The mean S-IgE (78 kU/l) of the children with current symptoms differed significantly ( p <0.001) from that (19 kU/l) of the non-atopic ones. There was no relationship between S-IgE and the stage of puberty. Ten of the 11 children with positive RAST, but no atopy/allergy intially, developed clinical atopy/allergy during the follow-up.     

Total IgE in urban Black South African teenagers: The influence of atopy and helminth infection

Total IgE levels are usually elevated in allergic diseases, being highest in atopic eczema, followed by atopic asthma and allergic rhinitis. Genetic factors are believed to play a role in total IgE levels, with higher levels seen in Black African subjects. Total IgE is also raised in parasite infection. Thus, the higher total IgE levels in Black Africans could be because of environmental rather than genetic factors. Few studies have investigated the usefulness of total IgE levels in the evaluation of atopy in Black Africans. The objective of this study was to determine the total IgE levels in unselected urban Black African high school children and to correlate this with atopy and ascaris sensitization. Atopic status was assessed by means of specific allergen sensitization (skin prick tests to eight inhalant and four food allergens), self-reported asthma and bronchial hyper-responsiveness measured by methacholine challenge. Ascaris sensitization was assessed by means of ascaris IgE measured by CAP-RAST. Total IgE levels were markedly skewed toward the left and were not distributed in a Gaussian or a log-normal distribution. Skin prick tests were positive for aeroallergens in 32.3% of subjects. Thirty four percent had elevated ascaris IgE. Total IgE was higher in atopic vs. non-atopic subjects and correlated with the number of positive skin prick tests, self-reported asthma and bronchial hyper-responsiveness. Subjects without allergy (or) atopy had a median total IgE of 80–90 kU/I. In addition total IgE correlated with ascaris IgE. Subjects with no ascaris sensitization had median total IgE of 77.1 kU/l. Subjects with neither atopy/asthma nor ascaris sensitisation had a median total IgE of 69.9 kU/I, similar to the levels seen in people of other genetic origins. This study suggests that helminthic infection rather than genetic differences, may be the major determining factor of IgE levels in certain populations.     

变态反应性疾病患儿血清特异性IgE检测的临床意义

目的　探讨血清特异性IgE(sIgE)与儿童变态反应病发病的关系 ,为临床防治提供依据。 方法　采用法玛西亚公司的免疫CAP诊断系统 ,以荧光酶联免疫法测定sIgE。 结果　 71例患儿中可查到 5 4例 4 8种变应原阳性的sIgE ,有些患儿对多种变应原呈阳性反应。支气管哮喘患儿阳性检出率为 74 % (37∶5 0 ) ;变应性鼻炎患儿阳性检出率为 6 4 % (7∶11) ;特应性皮炎及湿疹患儿阳性检出率为 80 % (8∶10 )。主要阳性变应原为户尘螨、屋尘、蒿草、烟曲霉等吸入性变应原和鸡蛋白、牛奶、花生、黄豆等食物性变应原。年幼儿组 (3～ 6岁 )以食物性变应原为主 ;年长儿组 (7～ 15岁 )以吸入性变应原为主。对上述 8种变应原的sIgE两组之间定量比较 ,经秩和检验发现吸入性变应原蒿草的sIgE在组间有明显差异 ,年长儿组高于年幼儿组 (P <0 0 5 ) ;食物性变应原牛奶的sIgE在组间有明显差异 ,年幼儿组高于年长儿组 (P <0 0 5 )。结论　上述 8种变应原是引起太原地区儿童变态反应病的主要变应原 ,随年龄增长血清中吸入性变应原的sIgE的阳性率增多 ,食物性变应原的sIgE的阳性率减少 ;sIgE对外源性变态反应病阳性检出率高。     

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目的比较3~14岁哮喘和变应性鼻炎患儿吸入性致敏原分布特征的异同。方法2004-10—2005-10,北京儿童医院对527例哮喘和620例变应性鼻炎患儿进行吸入性致敏原皮肤点刺试验(skin prick test,SPT),分析比较检出阳性的致敏原在两组病例中的分布特征。结果哮喘和变应性鼻炎患儿SPT阳性检出率分别为77·8%和78·9%(χ2=0·823,P>0·05)。户尘螨、粉尘螨、交链孢霉、猫上皮、艾蒿是两种疾病主要致敏原。哮喘患儿户尘螨、粉尘螨、混合霉菌的阳性率分别为64·6%、59·8%、8·8%,均高于变应性鼻炎患儿(49·5%、47·9%、3·9%,均P<0·05)。变应性鼻炎患儿杂草花粉和艾蒿的阳性率分别为25·6%、26·0%,均高于哮喘患儿(19·3%、19·3%,均P<0·05)。40·2%的哮喘和46·2%的变应性鼻炎为单致敏原阳性。尘螨霉菌混合致敏及尘螨宠物混合致敏在哮喘和变应性鼻炎中最为常见。结论尘螨、霉菌、夏秋季花粉和宠物是3~14岁哮喘和变应性鼻炎患儿主要吸入性致敏原,两病具有相似的致敏原分布特征,但尘螨及霉菌过敏多见于哮喘,夏秋季花粉过敏多见于变应性鼻炎。     

Development of atopic disease in relation to family history and cord blood IgE levels

The cumulative incidence of atopic disease from birth to about 11 yr of age and the prevalence during the 11th year was investigated in a cohort of 1654 non-selected children by an evaluated questionnaire. The total cumulative incidence of obvious atopic disease was 32. 5%, of bronchial asthma 5. 3%, and allergic rhinoconjunctivitis 14. 4%. The prevalence of itopic disease was 23. 7%. Obvious atopic disease developed in 67% of children with cord blood IgE ≥ 0.9 kU/l and a further 15% developed probable atopic disease. The positive predictive value of a family history of atopic disease was 45%. Children with a high cord blood IgE had a 5-fold increased risk for developing bronchial asthma. The sensitivity of cord blood IgE determination using 0.9 kU/l as cut-off was only 26%. Therefore, it can not without modifications be recommended as a single screening test. Neonatal IgE determination is., however, suitable, if used in conjunction with the family history, for identifying candidates at high risk for early development of atopic disease, e. g. for evaluation of the effect of preventive measures. Parents tend to forget symptoms (25%) that their children presented some years ago. Questionnaires are thus more suitable for establishing prevalence compared with cumulative rate of atopic disease.     

Allergic factors associated with the development of asthma and the influence of cetirizine in a double-blind, randomised, placebo-controlled trial: First results of ETA®

There is a common progression known as the allergic march from atopic dermatitis to allergic asthma. Cetirizine has several antiallergic properties that suggest a potential effect on the development of airway inflammation and asthma in infants with atopic dermatitis. Methods. Over a two year period, 817 infants aged one to two years who suffered from atopic dermatitis and with a history of atopic disease in a parent or sibling were included in the ETAC^® (Early Treatment of the Atopic Child) trial, a multi-country, double-blind, randomised, placebo-controlled trial. The infants were treated for 18 months with either cetirizine (0.25mg/ kg b.i.d.) or placebo. The number of infants who developed asthma was compared between the two groups. Clinical and biological assessments including analysis of total and specific IgE antibodies were performed. Results. In the placebo group, the relative risk (RR) for developing asthma was elevated in patients with a raised level of total IgE (≥ 30 kU/I) or specific IgE (≥ 0.35 kUA/I) for grass pollen, house dust mite or cat dander (RR between 1.4 and 1.7). Compared to placebo, cetirizine significantly reduced the incidence of asthma for patients sensitised to grass pollen (RR = 0.5) or to house dust mite (RR = 0.6). However, in the population that included all infants with normal and elevated total or specific IgE (intention-to-treat - ITT), there was no difference between the numbers of infants developing asthma while receiving cetirizine or placebo. The adverse events profile was similar in the two treatment groups. Discussion. Raised total IgE level and raised specific IgE levels to grass pollen, house dust mite or cat dander were predictive of subsequent asthma. Cetirizine halved the number of patients developing asthma in the subgroups sensitised to grass pollen or house dust mite (i.e. 20% of the study population). In view of the proven safety of the drug, we propose this treatment as a primary pharmacological intervention strategy to prevent the development of asthma in specifically sensitised infants with atopic dermatitis.     

The natural history of peanut allergy in young children and its association with serum peanut-specific IgE

OBJECTIVES: To observe the nature and frequency of adverse reactions caused by accidental peanut exposure in young children with clinical peanut hypersensitivity and to determine the value of serum peanut-specific IgE levels during follow-up. STUDY DESIGN: Eighty-three children with clinical peanut hypersensitivity diagnosed before their fourth birthdays were contacted yearly to track adverse peanut reactions. Serum peanut-specific IgE levels were determined in 51 of 83 subjects. RESULTS: Fifty-eight percent (31/53) of subjects followed up for 5 years experienced adverse reactions from accidental peanut exposure. Regardless of the nature of their initial reaction, the majority with subsequent reactions (52%, 31/60) experienced potentially life-threatening symptoms. The group with isolated skin symptoms (11/51, 22%) had lower serum peanut-specific IgE levels than the group with respiratory and/or gastrointestinal symptoms (40/51, 78%) (median: 1.25 kU(A)/L vs 11. 65 kU(A)/L, P =.004, Wilcoxon rank sums test). Despite this, there was no threshold level below which only skin symptoms appeared to occur. Four selected subjects had negative double-blind placebo-controlled food challenge responses to peanuts during follow-up. CONCLUSIONS: The majority of children with clinical peanut hypersensitivity followed up for 5 years will have adverse reactions from accidental peanut exposure. Symptoms experienced during subsequent adverse peanut reactions may not be consistent with symptoms reported during initial reactions. Therefore proper education regarding peanut avoidance and treatment of adverse reactions is necessary in all cases of clinical peanut hypersensitivity. Young children who are allergic to peanuts can lose clinical hypersensitivity.     

Food allergy as seen by an allergist

The clinical expression of allergic disease is the consequence of a series of complex gene-environment interactions that occur at the materno-fetal interface and throughout infancy, leading to persistence of the Th2 immune response. It has been proposed that atopic eczema is the cutaneous manifestation of a systemic disorder that also gives rise to asthma, food allergy, and allergic rhinitis. The recent emergence of genes regulating epidermal barrier function has raised the question of whether the skin barrier in atopic eczema is defective from the outset, rendering the epidermis "leaky," thereby increasing the risk of allergen penetration and the succeeding inflammatory reaction that contributes to atopic eczema. Food allergic sensitisation and eczema frequently coexist during the first 2 years of life, and food allergy is more prevalent in infants and children with moderate to severe eczematous inflammation. The majority of food allergic reactions are caused by 8 foods, with milk, egg, and peanut occurring with greatest frequency. The acquisition of food-specific tolerance occurs predominantly with foods in which the epitopes are grouped together in a conformational structure (milk, egg, wheat, soy), whilst it rarely occurs in patients allergic to foods in which the epitopes are arranged in a linear fashion (nuts, seeds, fish). Better tests and novel therapies, such as immunotherapy and oral tolerance induction, are required for the management of food allergy.     

Peanut allergy and allergic airways inflammation

Hughes JL, Brown T, Edgar JD, Shields MD. Peanut allergy and allergic airways inflammation.
Pediatr Allergy Immunol 2010: 21: 1107–1113.
© 2010 John Wiley & Sons A/S Asthma is a major risk cofactor for anaphylactic deaths in children with peanut allergy. Peanut allergy is generally thought to be a lifelong condition, but some children outgrow their coexistent asthma. It has recently been shown that children who have ‘outgrown’ their asthma symptoms may have ongoing eosinophilic airways inflammation. The need for regular inhaled corticosteroid treatment in peanut allergic children and adolescents who have outgrown their asthma is however unclear. The aims of our study were to look at fractional exhaled nitric oxide levels (FeNO), as a non‐invasive marker of eosinophilic airways inflammation, in peanut allergic children and assess whether children with outgrown asthma had elevated levels. Children with peanut allergy were recruited at two pediatric allergy clinics in Belfast, UK. Exhaled nitric oxide levels (FeNO) were measured using the Niox Mino in all children. Of the 101 peanut allergic children who consented for enrolment in the study, 94 were successfully able to use the NIOX Mino. Age range was 4–15 yr (median 10 yr); 61% were boys. Thirty (32%) had never wheezed, 37 (39%) had current treated asthma, 20 (21%) had at least 1 wheezing episode within the last year but were not taking any regular asthma medication (wheeze no treatment), and 7 (7%) had outgrown asthma. All children with outgrown asthma had elevated levels of FeNO (>35 ppb), and 75% of children defined as ‘wheeze no treatment’ had elevated FeNO levels (>35 ppb). Outgrown asthma and children defined as ‘wheeze no treatment’ had higher levels of FeNO than those with no history of wheeze or current treated asthma (p = 0.003). In children with peanut allergy, we found that those who had outgrown asthma had elevated FeNO levels in keeping with ongoing eosinophilic airways inflammation.     

Measurement of Ara h 1-, 2-, and 3-specific IgE antibodies is useful in diagnosis of peanut allergy in Japanese children

To cite this article: Ebisawa M, Movérare R, Sato S, Maruyama N, Borres MP, Komata T. Measurement of Ara h 1-, 2-, and 3-specific IgE antibodies is useful in diagnosis of peanut allergy in Japanese children. Pediatr Allergy Immunol 2012: 23: 573-581. ABSTRACT: Background: Food challenges are time-consuming, expensive, and not always possible to perform. Therefore, new tools to diagnose food allergy are desired. The aim was to evaluate IgE antibodies to peanut allergens in the diagnosis of peanut allergy in Japanese children using ImmunoCAP(?) and IgE immunoblotting. Methods: The study included 2-13-yr-old consecutive patients (n?=?57) referred to our specialist clinic for investigation of current peanut allergy using food challenge. All children had a previous doctor's diagnosis of peanut allergy and were on elimination diet. Serum samples were analyzed for IgE reactivity to peanut, recombinant (r) Ara h 1, 2, 3, 5, 8, and 9. IgE immunoblotting (n?=?23) was performed using extracts from raw and roasted peanut. Results: Twenty-six of the children failed (allergic group), and 31 passed the peanut challenge (tolerant group). The rAra h 2 ImmunoCAP test was superior in its ability to differentiate between children in the allergic and tolerant groups with a sensitivity and specificity of 88% and 84%, respectively (cutoff, 0.35?kU(A) /l). The combination of rAra h 1, 2, and 3 resulted in a higher specificity (94%) when IgE to all of them was the criteria for positivity. ImmunoCAP generally showed a good agreement with immunoblotting using both raw and roasted peanut for IgE reactivity to Ara h 1, 2, and 3. Conclusions: Measurement of IgE antibodies to rAra h 1, 2, and 3 is useful in the diagnosis of peanut allergy and in the investigation of reactions to raw and roasted peanut.     

Food composition: antigens

Relatively few food antigens have been purified to homogeneity and completely characterized. These include Gad c I from codfish; Sin a I from mustard seed; casein and beta-lactoglobulin from cow's milk; and ovalbumin, ovomucoid, and conalbumin from eggs. Multiple allergens are present in crustaceans, legumes, and cereal grains. Most vegetable seed allergens are proteins; refined oils from these seeds (peanut, soybean, sunflower) contain no nitrogen and are thus non-allergenic. Many food allergens are shared with pollens, so that pollen-sensitive persons may exhibit itching of the tongue and palate when the cross-reacting food is ingested.     

Hay fever and predictive value of prick test and specific IgE antibodies: A prospective study in children

Little is known from population-based studies in children about the diagnostic values of allergen-specific IgE antibodies (RAST) and skin prick test (SPT) with respect to hay fever. We aimed to determine and compare the diagnostic values of SPT and RAST to aeroallergens with respect to the incidence of hay fever cases in schoolchildren at different cut-off points. A prospective cohort study was performed on 1100 school children (5–7 and 8–10 years). Information on a doctor's diagnosis of hay fever was obtained by questionnaire and allergic sensitization to grass and birch pollen, cat, and Dermatophagoides pteronyssinus were measured using SPT and RAST between September 1992 and July 1993. Thirty-eight children give a history of hay fever (3.5%) in 1992/93 and additionally 37 cases occurred until 1996. Allergic sensitization was present in 17.9% (SPT), 30.2% (RAST) and more frequent in children with a history of hay fever (SPT: OR 11.7, 5.5–24.7; RAST: OR 10.6, 4.3–26.4). This difference was most pronounced for sensitization to pollen allergens. The sensitivity, specificity, positive and negative predictive values (PPV, NPV) for SPT and RAST were 65.6, 83.7, 11.9, 98.6 and 79.3, 71.6, 9.3, 99.0, respectively, with differences for specificity being significant (p < 0.001). Whereas NPV were equally high for SPT (99.2) and RAST (99.3), the incidence of hay fever cases were predicted rather poorly though somewhat better by SPT than by RAST (PPV 16.7 vs. 9.8; p < 0.001) initially. With increasing cut-off point for RAST reactivity, the PPV increased and reached 25.0 at 17.5 kU/l, whereas the NPV decreased to 97.9, which was lower than that of SPT reactivity (p < 0.01). At the cut-off point of 1.5 kU/l almost identical predictive values for SPT and RAST were obtained. SPT and RAST perform better in the negative than positive prediction of hay fever cases in epidemiological studies. Differences in the predictive capabilities depend on the chosen cut-off point for RAST reactivity.     

Hypokalaemia following nebulized salbutamol in children with acute attack of bronchial asthma

Objective : To determine whether use of nebulized salbutamol therapy for treatment of an acute attack of asthma in children is associated with hypokalaemia and if so what is its frequency, severity and effect on recovery.
Methodology : Forty-six children, aged 10 months to 12 years (mean 7.9±1.5 years) with acute attack of bronchial asthma, treated initially with three doses of nebulized salbutamol 0.15-0.3mg/kg, every 30 min participated in the study. Blood for serum potassium was obtained at the beginning and after three doses of nebulized salbutamol therapy, before administering other drugs.
Results : The mean±SD serum potassium level decreased marginally from 3.9±0.5mEq/L to 3.7±0.5mEq/L ( P <0.05). A decrease in serum potassium concentration was noted in 26 (56.5%) and hypokalaemia (serum potassium <3.5 mg/L) in 17 (39%) patients. It was more frequent in patients who had received oral salbutamol for the preceding 7 days. The average time taken for recovery was longer in patients who had hypokalaemia than those who had normal serum potassium concentration (8.6±2.7 h vs 6.5±2.7 h; P <0.005).
Conclusions : Hypokalaemia may occur in about one-third of patients treated with three doses of nebulized salbutamol therapy, especially those on prior oral salbutamol therapy. The monitoring of serum potassium concentration may be warranted in such patients.     

Quantification of IgE antibodies simplifies the classification of allergic diseases in 4-year-old children. A report from the prospective birth cohort study – BAMSE

Allergic diseases are common among small children, but it is still unclear how immunoglobulin E (IgE) antibodies to ambient allergens are distributed in a population‐based prospective material of children at 4 years of age. The study is based on 75% (n = 4089) of all eligible children from northern Stockholm, born between 1994 and 1996 in pre‐defined geographical areas. Data on exposure and outcome were obtained by parental questionnaires when the child was 3 months and 4 years of age. Of the 92% who responded to the 4 years of age questionnaire, serum was obtained in 88% of these children for analysis of IgE antibodies performed with Pharmacia CAP system^TM (Phadiatop^® and food mix fx5^®). An antibody level ≥0.35 kU_A/l was considered as positive. A positive Phadiatop^® or fx5^® was found in 24% of the 4 years old children. A rather poor correlation was found between the two tests (r = 0.39). Occurrence of IgE antibodies ≥3.5 kU/l for both Phadiatop^® and fx5^® in combination could predict any suspected allergic disease [asthma, rhinitis, atopic eczema dermatitis syndrome (AEDS) and allergic reaction to food] to 97.4%. However, the presence of ≥3.5 kU_A/l of Phadiatop^® or fx5^® used as single tests only, was far less efficient to predict any allergic disease. The two mixes of airborne and food allergens were also associated, not only to the severity of the allergic disease in terms of number of organ involved, but also to the severity of recurrent wheeze, in particular in boys with a positive Phadiatop^® who exhibited significantly limited peak flows compared to those with a negative test. Already at the age of 4, one child in four is sensitized to an allergen as assessed by Phadiatop^® or food mix (fx5^®). The presence of IgE antibodies seems not only to predict allergic diseases in this age group, but also relates to severity of such diseases, in particular to asthma. Notable, there was a poor correlation between Phadiatop^® and fx5^® that needs to be considered when identifying allergic diseases in young children. The study demonstrates that quantification of IgE antibodies in blood may be beneficial, not only to diagnose allergic diseases in young children, but especially to serve as a marker of severity of asthma.     

High prevalence of sensitization to aeroallergens in children 4 yrs of age or younger with symptoms of allergic disease

The assumption that sensitization to aeroallergens is rare in preschool children is based on population studies in which most subjects have little or no symptoms of atopic disease. We assessed the prevalence of atopic sensitization in children 0 to 4 yr of age presenting with symptoms of allergic disease by reviewing results of all specific immunoglobulin (IgE) tests performed in our hospital laboratory in children 4 yr of age or younger between 1985 and 2003. Tests were ordered by general practitioners or hospital‐based pediatricians in children presenting with symptoms of allergic disease. Specific IgE tests to a panel of common food and inhalant allergens were performed in 2946 children; a specific IgE concentration >0.35 kU/l was considered positive. Overall, 505 (17%) tests were positive to aeroallergens: 346 (12%) for house dust mite, 257 (9%) for dog dander, 240 (8%) for cat dander, and 197 (7%) for grass pollen. Positive tests were more common in boys (19.2%) than in girls (14.2%, p < 0.01), irrespective of age. Although sensitization to food allergens was more common in 0‐<3 yr olds, aeroallergen and food allergen showed comparable prevalence rates in 3‐<5 yr olds. Sensitization to aeroallergens is common in preschool children with symptoms of allergic disease, and more common in boys than in girls. Screening tests for allergy in infants and toddlers should include inhalant allergens.     

Atopic disease in preadolescence - an evaluation of questionnaires, association with cord blood IgE and month of birth

During a prospective study of 1654 children, followed from birth for 11 years, we evaluated the validity of a detailed questionnaire for establishing the prevalence of atopic disease in preadolescence. In 133 randomly selected children the questionnaire-based diagnoses were accurate in 128 (96.2%). If the cord blood IgE concentration was high (≥ 0.9 kU/l) then it was 1.7 times more common to have any prevalent atopic disease. The corresponding relative risk for multiple atopic disease was 11.5. Boys had high IgE levels significantly more often than girls, regardless of the degree of pubertal maturation. Sensitization to timothy pollen developed more often in children born during May compared to November. At least one allergy test (IgE, Phadiatop or SPT) was positive in 20 of 70 (28.6%) 11-year-old children with no history of atopic disease, indicating latent allergy. Among the healthy children with positive tests, those with cord blood IgE ≥ 1.3 kU/l were over-represented. IgE concentrations at 11 years of age corresponded poorly with neonatal IgE concentrations, indicating that after birth environmental influences are more important for the present IgE level than genetic factors.