Atopy in children with and without a family history of atopy. II. Skin reactivity

Atopic features in early childhood autism

BACKGROUND

Autism is a developmental disorder of unknown etiology. Sensitivity to dietary and environmental antigens has been considered in its pathogenesis.

AIM

To examine immediate hypersensitivity in early childhood autism.

METHODS

We investigated 30 autistic children (23 boys, seven girls 2-4 years old) for atopic history, serum IgG, IgA, IgM, IgE levels, and skin prick tests (SPT) with 12 common antigens.

RESULTS

Nine/30 autistic children (30%) and 1/39 (2.5%) age-matched neurological controls from the same hospital had a family history suggestive of atopy (p<0.005). No patient in the autism and 28% in control group had symptoms of respiratory allergy (wheezing or asthma) (p<0.005), and 6/30 (20%) autistic vs. 7/39 (17%) control children had history suggesting other allergic disorders (p=ns). Eleven/23 (47.8%) autistic children had at least one positive skin test, similar to age-matched population controls. Serum IgG, IgA, and IgM levels were within age-appropriate limits. Serum IgE was elevated in four patients (13.3%). Specific IgE levels were negative in four cases with multiple SPT positivity.

CONCLUSIONS

This study suggests allergic features based on history, skin tests, and serum IgE levels are not frequent in young autistic children despite family history. This discrepancy between predisposition and manifestation might imply immunological factors or environmental conditions.

Respiratory morbidity 20 years after RSV infection in infancy

Epidemiological data suggest that respiratory syncytial virus (RSV) infection in early life is a risk factor for later asthma. There are no prospective studies on RSV infection starting from infancy progressing through childhood into adulthood. We followed up a cohort of children, hospitalized for RSV bronchiolitis or RSV pneumonia before age 24 months, until age 18-20 years. The aim of the study was to evaluate early RSV infection as a risk factor for asthma, bronchial reactivity, and lung function abnormalities in young adults. The participants filled in a questionnaire on asthma and asthma-like symptoms. The clinical study included flow-volume spirometry (FVS), methacholine inhalation challenge (MIC), home PEF (peak expiratory flow) monitoring, and skin prick tests (SPT) to common allergens. Asthma was present in 17-22% of 36 index subjects, depending on asthma definition, compared to 11% of 45 controls. Furthermore, FEV% and MEF25 were lower, and MEF50 tended to be lower, in index than in control subjects. One or more abnormal lung function results were found in 16 (44%) index subjects, but only in 5 (11%) controls (P < 0.01). Bronchial reactivity (PD20 <4,900 microg methacholine) was demonstrated in 16 (46%) index subjects and 14 (32%) controls (NS). At least one positive SPT result was present in 21 (60%) index subjects; 6 (29%) had asthma (NS vs. nonatopic index subjects); 13 (62%) had abnormal lung function (P < 0.05); and 14 (67%) had bronchial reactivity (P < 0.01). In the logistic regression adjusted for atopy, as defined by SPT positivity, RSV infection in infancy was an independent risk factor for lung function abnormality (one or more abnormal results in FVS; OR, 5.27; 95% CI, 1.60-17.36), and also for decreased FEV% and MEF50 when these were analyzed separately. However, RSV infection in infancy was not a significant risk factor for asthma or bronchial reactivity. In young adults, lung function abnormalities may be associated with RSV infection which required hospitalization in infancy.

Pulmonary functions in atopic and nonatopic asthmatic children

BACKGROUND

we examined how lung function and certain clinical and laboratory characteristics in asthmatic children were changed according to skin test positivity to aeroallergens.

METHODS

a skin prick test was conducted using standardized extracts of 10 different allergens in 56 children with bronchial asthma, aged 5-15 years, in Dicle University Hospital. Lung function was measured by Microplus spirometer.

RESULTS

among the 56 subjects, asthma was classified as mild in 16, moderate in 42 and severe in 3. At least one skin prick test was positive (monosensitized) in 35 subjects (62 %) and positive reactivity to two or more aeroallergens (polysensitized) was found in 17 subjects (30 %). Positive skin test reactions to aeroallergens were associated with a decrease (as percentage of the predicted decrease) in FEV1, FVC and PEF values. Significant differences were also found between prick test-positive and -negative asthmatics in duration of breastfeeding (8.5 5 months vs 15 7 months, respectively, p < 0.007), age at which cow's milk had been started (5.7 1.6 vs 10.5 5.4, p = 0.004); total serum IgE concentration (350 221 IU/ml vs 234 164 IU/ml, p = 0.02), age at onset of asthma symptoms (2.5 1.9 years vs 4.1 2.2 years) and number of asthma attacks per year (7.0 3.1 vs 5.2 3.5, p = 0.012). When one-way ANOVA and a post-Hoc test were used, asthma attacks were more frequent and severe and allergic conjunctivitis symptoms were more frequent in the polysensitized group than in the nonsensitized and monosensitized groups (p = 0.03).

CONCLUSIONS

children with positive skin prick test results, especially those with combined sensitivity to dust mite, cat and dog, were at increase risk of more severe asthma.

Immunoglobulin G antibodies to moulds in school-children from moisture problem schools

BACKGROUND

The purpose of the present study was to evaluate mould-specific immunoglobulin G (IgG) antibodies in children exposed to moisture and mould problems in their school, and the association between IgG antibodies and mould allergy, active or passive smoking and respiratory symptoms.

METHODS

IgG antibodies were studied to 24 moulds in 93 children from three moisture problem schools and in 33 children from a reference school. The antibodies were measured by enzyme-linked immunosorbent assay and compared to positive adult sera.

RESULTS

There were no significant differences in mould-specific IgG concentrations between exposed and non-exposed school-children. Antibodies to moulds common in moisture damaged buildings were associated with allergic diseases, as well as with mould-specific immunoglobulin E (IgE) or skin prick test (SPT) findings. Aspergillus fumigatus and A. versicolor were the moulds with the most consistent findings. Active and passive smoking were associated with low levels of antibodies to many moulds. Though the association between asthma, wheezing or cough symptoms, and IgG to moulds was not significant, 7 (39%) of the 18 children with multiple (> 7) elevated IgG findings suffered from asthma or wheezing.

CONCLUSIONS

Allergy was, but asthma was not, associated with IgG antibodies to the moulds that can be found in moisture damaged buildings. However, no association was found between IgG antibodies to moulds and exposure to moisture and moulds in school.

Frequency and specific sensitization to inhalant allergens within nuclear families of children with asthma and/or rhinitis

OBJECTIVE

The purpose of this study was to investigate the frequency of allergy in 85 families of pediatric patients with asthma and/or rhinitis.

METHODS

Families enrolled were drawn according to a table of randomization, from those whose children were referred the outpatient clinic of the Pulmonology Department of Gaslini Institute (Genoa, Italy). In patients and in both their mothers and fathers, allergic sensitization to the three most common classes of inhalant allergens (house dust mites, pollens, and animal danders) was evaluated by skin prick test.

RESULTS

As compared with their parents, children showed a similar prevalence of positive skin prick test (50.0% and 58.8%, respectively; chi 2 = 1.4; P > .1), but a significantly higher frequency of specific sensitization to house dust mites, pollens, or pets (P < .05, each chi 2). These differences were at least partially related to the higher frequency of polysensitization (i.e., sensitization to more than one class of allergens) in children than in their parents [chi 2 = 4.2, odds ratio (OR) = 2.3, 95% confidence interval (CI95%) = 1.0 to 5.1; P < .05). In addition, both in children (chi 2 = 5.8, OR = 11.3, CI95% = 1.4 to 81.5; P < .05] and in their parents (chi 2 = 7.4, OR = 4.8, CI95% = 1.5 to 16.7; P < .01), allergy to pollens was less frequent in monosensitized than in polysensitized families, while the prevalence of sensitization to house dust mites was similar in monosensitized and in polysensitized families. The analysis of the role of parental sensitization in the development of allergy in the offspring demonstrated that the prevalence of allergic children: (1) seemed to be higher, without reaching statistical significance, in families with sensitized parents than in those with non-sensitized parents (chi 2 = 0.41, P > .1) and (2) was higher in families with one or both polysensitized parents than in those with one or both monosensitized parents (chi 2 = 4.5, OR = 4.0, CI95% = 1.1 to 15.6; P < .05). In addition, within each family, the coincidence of sensitization to house dust mites was more frequent than that to pollens (60.0% and 36.0%, respectively; chi 2 = 7.6, OR = 4.5, CI95% = 1.5 to 14.3; P < .01), and it was not influenced by the number of parents sensitized to same allergen.

CONCLUSION

These data support the concept that, in addition to genetic predisposition, other factors (i.e., environmental exposure) may influence the development of specific sensitization in children with respiratory symptoms. The different sensitization found in this study between children and their parents occurred in a generation span, so as it is more likely to be related to environmental changes than to genetic factors.

Asthma and atopy in schoolchildren in a defined population

We investigated the frequency of allergic disorders, the pattern of allergen sensitization and serum total IgE concentration in a population-based sample of schoolchildren screened on the basis of respiratory symptoms (N = 244). The children were classified on clinical grounds into three groups, asthma (N = 43), other symptoms from lower airways (OSLA; N = 34) and control children (N = 167). The frequency of allergic disorders (allergic rhinitis, conjunctivitis or dermatitis) differed significantly between children with asthma (81%), children with OSLA (62%) and in control children (48%) (p < 0.001). The presence of at least one positive skin prick test result was equally common in children with asthma or OSLA (77%), but lower in control children (40%) (p < 0.001). Serum total IgE concentrations did not differ between the three groups. Two conclusions can be drawn: (i) there is a strong association between clinical allergy, skin reactivity and asthma in school age children, and (ii) a similar association is present between allergy and asthma-like conditions.

Influence of skin prick test criteria on estimation of prevalence and incidence of allergic sensitization in children

In a prospective cohort study on atopy in childhood, three skin prick tests (SPT) were performed in 1135 primary schoolchildren over a 2-year period. We studied the development of average sizes of allergen wheals in reactive children and of average sizes of histamine wheals in all children, and we investigated the influence of choice of SPT criterion on the prevalence and incidence of sensitization. A year-to-year increase of average allergen wheal sizes as well as of average histamine wheal sizes was observed. These increases seemed to be related to the natural growth of the children. Furthermore, an observer bias effect of the person who did the pricking on average wheal sizes was found. There were considerable differences in estimations of prevalences and incidences depending on the definition of SPT criterion. Estimations using a criterion based solely on the allergen wheal size were affected by variation of allergen wheal sizes caused by growth and observer effects. The ratio criterion was not influenced by observer effects, nor did it seem to be affected by aging effects. In conclusion, our data suggest that the ratio criterion, which relates the size of the allergen wheal to the size of the histamine wheal, is the most appropriate SPT criterion because it is not affected by growth of allergen wheals in childhood and it appears to compensate for possible observer bias.

Bronchial asthma after early childhood wheezing: a follow-up until 4.5-6 years of age

Over a period of 12 months from 1981 to 1982, 83 patients aged less than 2 years were treated in hospital for acute bronchiolitis. The children were followed-up prospectively; 68 (83%) completed the study until 4.5-6.0 years of age. At this age, 17 (25%) of the 68 children with bronchiolitis still suffered from wheezing attacks. These 17 asthmatics suffered from both atopic dermatitis (29 versus 6%) and allergic rhinitis (29 versus 8%) more frequently than non-asthmatic children. In contrast, positive results in the skin prick tests were almost equally common (29 and 20%) in asthmatic and non-asthmatic children. In these tests, allergies to birch pollen, timothy grass pollen and house dust mite were most common; asthma was particularly associated with house dust mite allergy. The presence of atopic dermatitis, elevated immunoglobulin E values and repeated wheezing episodes between 1 and 2 years of age were significant risk factors for later asthma. In conclusion, the risk for later asthma is increased after early childhood bronchiolitis; the frequency of asthma was 25% in the present study. Our results confirm that atopics are at a greater risk of developing asthma later in childhood than non-atopics; the risk was significant from 1 year of age onwards.

Early childhood risk factors for sensitization at school age

Early childhood risk factors for current sensitization were investigated by use of cross-sectional data of a longitudinal study in Southwest Germany. Information was gathered by questionnaires from 1812 families of whom 1470 children 6 to 8 years old were tested by means of a skin prick test (SPT) with seven aeroallergens. Groups with sensitization (n = 201; positive SPT to grass pollens 6.6%, Dermatophagoides pteronyssinus 6.5%, Dermatophagoides farinae 4.4%, cat dander 4.6%, any of the tested allergens 13.7%) are compared with children without sensitization (n = 1269). As risk factors for any sensitization parental atopy (odds ratio [OR]/95% confidence interval [95%CI]: unilateral 1.9/1.3 to 2.6; bilateral 2.8/1.5 to 5.2), low gestational age (1.9/1.1 to 3.2), and male gender (1.6/1.2 to 2.3) are statistically significant in multiple logistic regression. Former cat ownership is significantly related to sensitization to cat dander (2.7/1.4 to 5.5). Breast feeding, maternal smoking habits after the child's birth, prior exposure to pets, and social class are not important. In conclusion, our data suggest parental atopy, low gestational age, and male gender as independent risk factors for sensitization to aeroallergens at school age.

Genetic risk for asthma, allergic rhinitis, and atopic dermatitis

In order to explore the genetic risk of a child with a family history of allergies developing asthma, allergic rhinitis, or atopic dermatitis, questionnaires filled in by 6665 families were analysed. The data were collected in a population based cross sectional survey of 9-11 year old schoolchildren living in Munich and southern Bavaria. The relation between asthma, allergic rhinitis, and atopic dermatitis and the number of allergic first degree relatives, and the type of allergic disease was examined. Analyses were done separately for families with single or multiple allergic diseases. In families with one allergic parent the risk of the child developing asthma was increased by asthma in a parent, with an odds ratio (OR) of 2.6 (95% confidence interval 1.7 to 4.0) but not by parental allergic rhinitis with OR 1.0 (0.7 to 1.5) or atopic dermatitis, OR 1.0 (0.6 to 1.6). For allergic rhinitis the highest risk with OR 3.6 (2.9 to 4.6) was observed with allergic rhinitis of one parent, apparently lower for asthma of one parent, OR 2.5 (1.6 to 4.0) or atopic dermatitis, OR 1.7 (1.1 to 2.5). Children with parental atopic dermatitis had a high risk for atopic dermatitis, OR 3.4 (2.6 to 4.4), compared with children with parental asthma, OR 1.5 (1.0 to 2.2), or parental allergic rhinitis, OR 1.4 (1.1 to 1.8). Risk factors in families with combined allergies of two relatives (parents and siblings) were analysed separately for the different combinations. These results support the hypothesis that asthma, allergic rhinitis, and atopic dermatitis are multifactorial diseases brought about by various familial and environmental influences.

Diet in infancy and bronchial hyperreactivity later in childhood

Sixty-seven atopy-prone children (atopic family group, AFG) and 52 children with no family history of atopy (NAFG) were followed for 10 years. During infancy, the mothers of the newborn AFG children were advised to adjust their infants' diet, with a view toward minimizing the risk of atopy, and not to keep pets. Pulmonary function tests, methacholine inhalation challenge (MIC), and skin prick tests (SPT) were done in order to evaluate the bronchial reactivity and skin reactivity in the two groups. A pathological result in MIC was found in 20 (30%) of the AFG children and in 10 (19%) of the NAFG children. Such results of MIC were more common in the children with positive SPT results than in those without (67% vs. 24%). In regard to the diet consumed in infancy, MIC was pathological in 23% of children with and in 36% without prophylactic diet in infancy. For MIC, using the new, Spira electro 2 dosimeter equipment, the sensitivity was 75% and specificity 97%, but the predictive value for diagnosing bronchial asthma was only 25%. The important advantage of our method is that the degree of bronchial reactivity can be estimated by responses to increasing provocative doses. Our observations confirm that the new method is suitable for detecting bronchial asthma in clinical practice but it seems not to be optimal for epidemiological studies. We concluded that later bronchial hyperreactivity can not be diminished by avoiding home pets or providing a hypoallergenic diet during infancy.