Prevalence of atopic dermatitis in Japanese elementary schoolchildren

BACKGROUND: Although there have been several reports on the prevalence of atopic dermatitis (AD) in Japanese schoolchildren based on questionnaires, there has been no nation-wide study of the frequency of this condition diagnosed by dermatologists in regular health check-ups of schoolchildren. OBJECTIVES: The objective of this work was to evaluate precisely the prevalence of AD in elementary schoolchildren in Japan based on regular health check-ups by dermatologists. METHODS: In 2001/2, elementary schoolchildren: first graders (age 6-7 years) and sixth graders (age 11-12 years) were examined by dermatologists in eight prefectures of Japan (Hokkaido, Iwate, Tokyo, Gifu, Osaka, Hiroshima, Kochi and Fukuoka). In each prefecture, public elementary schools were randomly selected from urban and rural districts. We planned to examine about 700 schoolchildren in each of urban first, urban sixth, rural first and rural sixth grades from the eight areas, a total of 22 400 children (700 x 4 x 8). AD was diagnosed by the dermatologists based on the Japanese Dermatological Association criteria for the disease. RESULTS: The point prevalence of AD was 11.2% overall (2664 of 23 719) ranging from 7.4% (Iwate) to 15.0% (Fukuoka) in the eight areas. Seventy-four per cent, 24%, 1.6% and 0.3% of those afflicted were in the mild, moderate, severe and very severe groups, respectively. Overall, the prevalence of first graders was slightly higher than that of sixth graders (11.8% vs. 10.5%, P < 0.01). There was no apparent difference in prevalence between urban and rural districts, or between boys and girls. CONCLUSIONS: The prevalence of AD in Japanese elementary schoolchildren was about 10%, three-quarters of those being mildly affected. This is the first nation-wide study made of Japanese elementary schoolchildren examined by dermatologists to evaluate the frequency of AD.     

南京市2249名中小学生异位性皮炎调查分析

目的：了解南京地区青少年异位皮炎的发病情况。方法：对南京地区４所学校２２４９名７～１８岁年龄段的学生进行普查。结果：１９９８年５～６月南京地区青少年异位性皮炎时的时点患病率为０．８９％,其中城市患病率１．２５％,农村患病率为０．４８％,城市和农村男性患病率分别为１．６８％和０．８０％,女性为０．８２％和０．１８％。同时证实了Ｗｉｌｌｉａｍｓ标准在我国普遍人群应用有较好的诊断效率。结论：（１）１９９８年５～６月南京地区青少年异位性皮炎的时点患病率表现为城市高于农村,男性高于女性;（２）Ｗｉｌｌｉａｍｓ标准适用于我国７～１８岁年龄段人群的流行病学调查。     

Epidemiology of atopic dermatitis in primary schoolchildren in Turkey

Abstract:  The present study aimed to investigate the prevalence of atopic dermatitis in primary schoolchildren in Denizli, Turkey, and to determine the possible risk factors for atopic dermatitis in home environment. A self-administered questionnaire was handled to the parents of 2,100 children aged 7 to 15 years, from three randomized primary schools and 1,644 (78.9%) completed and returned the questionnaire. The questionnaire included the United Kingdom Working Party diagnostic criteria and asked about conditions that could affect the course of atopic dermatitis. The prevalence of atopic dermatitis and coexisting factors that may affect the course of the disease were evaluated in 1,644 children (825 girls and 819 boys). The prevalence of atopic dermatitis was detected as 4.9%. Passive smoking, heating systems either in the house or in the child's bedroom, and the number of people living in the house had no significant effect (p > 0.005). The difference in prevalence of atopic dermatitis between developed and developing countries is striking. The determination of the factors that have an influence in this issue will probably enable us to change the course and frequency of atopic dermatitis.     

Is the prevalence of atopic dermatitis increasing?

Several studies have suggested that the prevalence of atopic dermatitis has increased over the last three decades, and similar trends have been reported with asthma and hay fever. However, in common with other 'allergic' disease, the definition and measurement of atopic dermatitis in populations has been fraught with problems and has led to difficulties in separating any real changes in disease prevalence from secular changes in diagnosis. In this article, the evidence surrounding the claims of an increased prevalence of atopic dermatitis is examined, and possible reasons for such a change are suggested.     

The prevalence of Malassezia yeasts in patients with atopic dermatitis, seborrhoeic dermatitis and healthy controls

Cultures for Malassezia yeasts were taken from both normal-looking skin and lesional skin in 124 patients with atopic dermatitis, 16 patients with seborrhoeic dermatitis and from normal skin of 31 healthy controls. Positive Malassezia growth was found in fewer patients with atopic dermatitis (56%) than in patients with seborrhoeic dermatitis (88%) or in healthy controls (84%, p<0.01). In the patients with atopic dermatitis, fewer positive cultures were found in lesional (28%) than in non-lesional skin (44%, p<0.05), while positive cultures were found in 75% of both lesional and non-lesional skin of patients with seborrhoeic dermatitis (not significant). M. sympodialis dominated in patients with atopic dermatitis (46%) and in healthy controls (69%). In patients with seborrhoeic dermatitis both M. sympodialis and M. obtusa were cultured in 43%. A Malassezia species extract mixture would increase the possibility of detecting IgE sensitization to Malassezia in patients with atopic dermatitis.     

No significant increase within a 3-year interval in the prevalence of atopic dermatitis among schoolchildren in Baranya County, Hungary

BACKGROUND: The prevalence of atopic dermatitis (AD) in children has significantly increased worldwide in the past decades. Although it is well known that the number of AD patients has also been growing in Hungary, there are only a few published prevalence studies that allow international comparisons. OBJECTIVES: The aim of this study was to estimate the prevalence of AD among schoolchildren in Baranya County in 2005 and to compare the data with those from 2002. METHODS: The data from the 1454 children (771 girls, 683 boys) surveyed in 2002, and 1454 children (760 girls, 694 boys) surveyed in 2005, respectively, aged 7-14 years were analysed. The distinct populations of the 7- to 9-year-old age groups were separately compared in relation to their lifetime AD prevalence. RESULTS: The prevalence of AD accounted for 15.1% in 2002, and 16.1% in 2005. In the compared distinct 7- to 9-year-old populations the prevalence rates were 17.0% in 2002 and 17.1% in 2005. There were no statistically significant differences between the data of the two surveys. CONCLUSIONS: The results indicate the high prevalence rate of AD nearly approaching the markedly high values registered in the welfare countries, and could indicate that AD has reached a plateau in Hungary.     

Community validation of the United Kingdom diagnostic criteria for atopic dermatitis in Romanian schoolchildren

Although the U.K. modification of Hanifin and Rajka's diagnostic criteria for atopic dermatitis (AD) for use in epidemiological studies has demonstrated good validity and repeatability when previously tested in a U.K. community setting, little is known about its performance in other countries where different cultural, educational and linguistic factors could impair validity. We used a questionnaire to test the validity of the U.K. criteria as a point prevalence measure of AD in 1114 Romanian schoolchildren aged 6–12 years against the clinical diagnosis of a dermatologist with an interest in AD, who was unaware of the questionnaire content and responses. The sensitivity and specificity of the U.K. criteria for AD in this setting was 74% and 99%, respectively, an improvement rather than a deterioration in validity when compared with the previous U.K. study. Test–retest repeatability for all of the questions pertaining to the U.K. criteria using the chance-corrected kappa statistic was high, with values of 0.72 and over. The positive predictive value of the criteria was lower than in the U.K. study (63% compared with 80%, respectively) due to the very low prevalence of AD in this study (2.4%). The validity of a parental report of 'eczema' was poor, with a sensitivity of 22%, specificity of 97% and positive predictive value of 18%. This study suggests that the U.K. criteria perform well in settings outside the U.K., although care has to be taken when using the criteria to ascertain cases in settings where the prevalence of AD is very low.     

Less common clinical manifestations of atopic dermatitis: prevalence by age

The common manifestations of atopic dermatitis (AD) appear sequentially with involvement of the cheeks in infancy, flexural extremities in childhood, and hands in adulthood. Although less common clinical manifestations are well described, they have not been the subject of epidemiologic studies to describe their prevalence in specific age groups. This observational, cross-sectional, comparative study included 131 children younger than 18 of both sexes with AD who attended the clinics of the Dermatology Department of the National Institute of Pediatrics in Mexico City. Patients were examined to determine the presence of infrequent clinical manifestations of AD during infancy, preschool and school age, and adolescence and stratified according to sex, age, and number of clinical signs. A chi-square test was used to detect differences according to age and sex. Logistic regression analysis was also performed. The main findings according to age were genital dermatitis and papular-lichenoid dermatitis variant in infants; atopic feet, prurigo-like, nummular pattern, and erythroderma in preschool and school-aged children; and eyelid eczema and nipple dermatitis in adolescents. The risk of development of nipple dermatitis and eyelid eczema increased with age, and the development of genital dermatitis decreased with age. The knowledge of the prevalence of less common clinical manifestations of AD according to age in different populations might be helpful in diagnosing incipient cases of AD.     

The epidermal barrier in atopic dermatitis

Epidermal barrier function is abnormal in individuals with atopic dermatitis (AD). It is controversial whether primary epidermal barrier abnormalities alone account for the physiological and clinical abnormalities found in those persons with AD or whether the observed barrier dysfunction is a consequence of primary immunologic abnormalities. Recent evidence is strengthening the argument for the former hypothesis. Attention to epidermal barrier care (ie, gentle skin care) has long been an important part of the therapy of AD. Advances in our understanding of the biology of the epidermal barrier and how this relates to the clinical manifestations of this disease has important consequences for new therapeutic approaches in the management of AD.     

The occurrence of atopic dermatitis in Greenland

Until recently there was no information available on the prevalence of atopic dermatitis in Greenland. Our objective was to determine the prevalence of atopic dermatitis in younger schoolchildren in Greenland. In the autumn of 2000 we used our previously elaborated questionnaire in a cross-sectional study of 954 schoolchildren aged 7-8 years, who lived in five Greenlandic towns. The findings were compared to data on atopic dermatitis from Denmark. The response rate was 65% (622). The lifetime prevalence of atopic dermatitis was calculated to be 14.0% (95% confidence interval 11.3-16.7) using our standard score criteria with an absolute lower limit estimate of 4.5%. Taking the response rate of 65% into consideration this study indicates that in 2000 the lifetime prevalence of atopic dermatitis among younger schoolchildren in Greenland was in the range of 10-15%.     

The role of infection in atopic dermatitis

explain this tendency to develop infections. A decrease in the number and function of CD8+ suppressor/cytotoxic T cells from peripheral blood of AD patients has been reported.2 This could explain the increased incidence of cutaneous viral and fungal infections observed in these patients. Monocytes from AD patients secrete increased levels of interleukin (IL)-10 that can inhibit T cell mediated responses.3 Leukocytes from patients with AD have been found to produce decreased amounts of interferon gamma (IFN-g),4 which is required for the     

The cutaneous pathology of atopic dermatitis

Sixteen skin biopsy specimens from early eruptive, evolving papules and well-developed plaques were obtained from eight patients with established atopic dermatitis. We found that the chronological and histopathological sequence begins with a perivascular interstitial spongiotic dermatitis, evolves into a psoriasiform microvesicular spongiotic dermatitis, which is sometimes focally lichenoid, and eventually concludes as a psoriasiform dermatitis. Thus, atopic dermatitis has characteristic and diagnostic histopathologic findings. These are portrayed and contrasted to what has been previously reported.     

天津市0～6岁儿童特应性皮炎患病率调查

目的了解天津市城市和农村0～6岁儿童特应性皮炎（AD）的患病率及患病因素。方法采取整群抽样方法，依据儿童哮喘和过敏国际研究协作组问卷，对天津市城市和农村0～6岁儿童进行问卷调查。结果本次调查涉及天津市城市和农村，收回问卷3749份，有效问卷3708份，有41份因填写不规范而未被录入数据库进行统计学分析。城市应答率为84．9％，农村应答率为79．3％，总应答率为82．7％。所调查人群的年龄在不同性别间及城市和农村问分布均衡。经过对调查资料的分析，儿童AD的患病率为2．9％，其中城市为3．5％，农村为2．4％，城市AD患病率高于农村（矿=3．98，P〈0．05）。结论天津市AD的患病率为2．9％，城市AD患病率为3．5％，农村AD的患病率为2．4％。