Worldwide variations in the prevalence of symptoms of atopic eczema in the International Study of Asthma and Allergies in Childhood

Increased plasma eotaxin in atopic dermatitis and acute urticaria in infants and children

BACKGROUND

The previously reported eotaxin overexpression in the lesional skin of atopic dermatitis (AD) led us to the assumption that circulating levels of eotaxin may be elevated too. We sought to investigate the plasma expression of eotaxin in children with skin allergy in relation to clinical activity and type of lesions.

METHODS

Plasma eotaxin was assayed in 78 infants and children, of whom 16 had AD, 19 had acute urticaria (AU), and 43 were healthy matched subjects. Seven children in the group of AU were resampled for plasma eotaxin after clinical remission.

RESULTS

The plasma eotaxin levels in AD (median=158 pg/ml, mean [SD]=168 [61] pg/ml) were significantly higher than the control values (median=60 pg/ml, mean [SD]=59.5 [18.5] pg/ml). Not only did patients with AU demonstrate elevated plasma eotaxin levels (median=126 pg/ml, mean [SD]=124 [33] pg/ml), but also a significant decline occurred on follow-up. The coexistence of angioedema with AU did not cause any further increase in plasma eotaxin expression. Plasma eotaxin levels were significantly higher in AD than in AU, probably reflecting the chronic nature of eczematous AD lesions. The plasma eotaxin levels did not correlate with serum total IgE, peripheral blood absolute eosinophil count, or age of the patients. However, there was a positive correlation between age and plasma eotaxin in the control group.

CONCLUSION

Our findings imply that circulating levels of eotaxin increase in AD and during flares of AU, probably to serve in the recruitment and activation of eosinophils. It may also represent a biomarker of lesional activity.

Psychosocial factors and adherence to treatment advice in childhood atopic dermatitis

Poor adherence to maintenance treatment for atopic dermatitis and anxiety about using topical steroids are common features seen among children with atopic dermatitis and their mothers. No systematic study exploring factors associated with adherence to treatment advice on atopic dermatitis has been carried out to date. This study seeks to generate hypotheses regarding the relationship between a range of psychosocial factors and adherence to treatment advice on atopic dermatitis. An anonymous self-completed questionnaire containing adherence items, psychosocial items, some demographic items, and attitudes to steroid use was given to 258 mothers of atopic dermatitis follow-up patients who attended the National Children's Hospital, Tokyo. Responses from 205 families (80%) with complete data were then analyzed to explore the correlation between each factor and to build a structure equation model. The strongest predictor of adherence to skin-care treatment was a good doctor-patient (mother) relationship, followed by the severity of the disease as perceived by the mother. Surprisingly, the mother's anxiety about using topical steroids had no significant influence on reported use of topical steroids nor on adherence to skin-care treatment. This may have been overcome by the well-established doctor-patient (mother) relationship. Maternal personality, husband's cooperation, and social support were indirectly correlated with adherence via the doctor-patient relationship. Maternal self-efficacy of treatment was strengthened by good doctor-patient (mother) relationship.

Fibronectin and fibrinogen contribute to the enhanced binding of Staphylococcus aureus to atopic skin

BACKGROUND

Staphylococcus aureus colonizes the skin lesions of more than 90% of patients with atopic dermatitis (AD). The mechanism for increased S aureus colonization in AD is unknown. However, the initial event in colonization requires adherence of S aureus to the skin.

OBJECTIVE

The purpose of this study was to examine the roles of various bacterial adhesins on S aureus binding to AD skin.

METHODS

In an attempt to delineate the mechanism behind this adherence process, an in vitro bacterial binding assay was developed to quantitate the adherence of various S aureus strains to AD, psoriatic, and normal skin sections. S aureus strains used in this study were obtained either from cultures of AD skin lesions or from genetically manipulated strains of S aureus that lacked specific microbial surface components recognizing adhesive matrix molecules (MSCRAMMs)--namely, fibronectin-binding protein (Fnbp), fibrinogen-binding protein (Clf), collagen-binding protein (Cna), and their parent strains. In addition, S aureus strains from patients with AD were pretreated with fibronectin or fibrinogen to block MSCRAMM receptors and interfere with binding.

RESULTS

Under all experimental conditions, binding of S aureus was localized primarily to the stratum corneum. Immunocytochemical staining of AD skin sections showed a redistribution of fibronectin to the cornified layer, an observation not seen in normal skin. S aureus binding to uninvolved AD skin was significantly greater than the binding to uninvolved psoriatic skin (P <.0001) and normal skin (P <.0005). The Fnbp-negative S aureus showed a significant reduction in binding to the AD skin (P <.0001) but not to the psoriatic and normal skin. In the AD skin, a significant reduction in the binding of S aureus was also observed in the Clf-negative strain (P <.0001) but not in the Cna-negative S aureus. Preincubation of S aureus with either fibronectin or fibrinogen also inhibited bacterial binding to AD skin (P <.0001).

CONCLUSION

These data suggest that fibronectin and fibrinogen--but not collagen--play a major role in the enhanced binding of S aureus to the skin of patients with AD.

Immunization and symptoms of atopic disease in children: results from the International Study of Asthma and Allergies in Childhood

OBJECTIVES

This study tested the hypothesis that immunization is related to the prevalence of atopic disease in childhood.

METHODS

We used data from the International Study of Asthma and Allergies in Childhood to perform an ecologic analysis of national and local immunization rates for tuberculosis, diphtheria and tetanus toxoids and pertussis (DTP), and measles and prevalence of atopic disease symptoms (asthma, allergic rhinoconjunctivitis, and atopic eczema).

RESULTS

In 13- to 14-year-old children, there were significant negative associations with local birth-year immunization rates for DTP and measles but none with rates for tuberculosis. No associations were found in 6- to 7-year-old children. No associations with national immunization rates were found.

CONCLUSIONS

International variations in childhood atopic diseases are unlikely to be explained by variations in immunization.

Validation of the Chinese translated version of ISAAC core questions for atopic eczema

BACKGROUND

The International Study of Asthma and Allergies in Childhood (ISAAC) was designed to allow international comparison of epidemiological data on atopic conditions in childhood. In so doing, further aetiological information would be obtained that in turn would provide a framework for future studies. The global ISAAC results on the prevalence of atopic dermatitis indicated a 60-fold variation recorded in different countries. Such a degree of difference may be partially due to the translated questionnaires that were not validated in all of the involved countries.

OBJECTIVE

To validate the Chinese version of the ISAAC core questions for atopic eczema.

METHODS

One thousand nine hundred and twenty children aged between 3 and 5 were randomly recruited from 13 kindergartens in Hong Kong. Using a dermatologist's clinical examination as the gold standard, we validated the Chinese version of the ISAAC core questions for atopic eczema. The Youden's Indexes obtained in our study were compared with those obtained in the United Kingdom's validation study.

RESULTS

The Youden's Indexes obtained in our study were significantly lower than those from the United Kingdom. The low scores were likely to be due to a reduction in the sensitivity of the Chinese questionnaire, which ranged from 23.5% to 70.6%.

CONCLUSION

Our findings indicate that the translated questionnaire is less effective than the English version in assessing the prevalence of atopic eczema. The indication of a low prevalence of atopic eczema among the Chinese population reported in previous studies was at least partially due to problems with the translated questionnaire.

Diet and asthma, allergic rhinoconjunctivitis and atopic eczema symptom prevalence: an ecological analysis of the International Study of Asthma and Allergies in Childhood (ISAAC) data. ISAAC Phase One Study Group

Several studies have suggested that the increasing prevalence of symptoms of asthma, rhinitis and eczema, could be associated with dietary factors. In the present paper, a global analysis of prevalence rates of wheeze, allergic rhinoconjunctivitis and atopic eczema was performed in relation to diet, as defined by national food intake data. Analyses were based on the International Study of Asthma and Allergies in Childhood (ISAAC) data for 6-7 and 13-14 yr old children. Symptoms of wheeze, allergic rhinoconjunctivitis and atopic eczema symptom prevalence were regressed against per capita food intake, and adjusted for gross national product to account for economic development. Dietary data were based on 1995 Food and Agriculture Organisation of the United Nations data for 53 of the 56 countries that took part in ISAAC phase I (1994/1995). The 13-14 year age group showed a consistent pattern of decreases in symptoms of wheeze (current and severe), allergic rhinoconjunctivitis and atopic eczema, associated with increased per capita consumption of calories from cereal and rice, protein from cereals and nuts, starch, as well as vegetables and vegetable nutrients. The video questionnaire data for 13-14 yr olds and the ISAAC data for 6-7 yr olds showed similar patterns for these foods. A consistent inverse relationship was seen between prevalence rates of the three conditions and the intake of starch, cereals, and vegetables. If these findings could be generalised, and if the average daily consumption of these foods increased, it is speculated that an important decrease in symptom prevalence may be achieved.

The relationship of per capita gross national product to the prevalence of symptoms of asthma and other atopic diseases in children (ISAAC)

BACKGROUND

Increasing prevalence and worldwide variation in asthma and other atopic diseases suggest the influence of environmental factors, at least one possibly related to socioeconomic wellbeing. This paper examines the relationship of symptoms of asthma, rhinitis and eczema with gross national product per capita (GNP per capita).

METHODS

The prevalences of atopic symptoms in 6-7- and 13-14-year-old children were assessed in 91 centres (from 38 countries) and 155 centres (from 56 countries), respectively, in the International Study of Asthma and Allergy in Childhood (ISAAC). These symptoms were related to 1993 GNP per capita for each country as reported by the World Bank. The relationships between symptoms of atopic diseases and infant mortality, the human development index and 1982 GNP per capita were also considered.

RESULTS

The countries in the lowest quartile of GNP per capita have the lowest median positive responses to all the questions on symptoms of asthma, rhinitis and eczema. There was a statistically significant positive association between wheeze in the last 12 months and GNP per capita in the 13-14-year age group, but not in the 6-7-year age group. There was also a positive association between GNP per capita and eczema in both age groups.

CONCLUSIONS

The positive associations between GNP per capita and atopic symptoms being of only moderate strength suggests that the environmental factors are not just related to the wealth of the country.

A 12-week study of tacrolimus ointment for the treatment of atopic dermatitis in pediatric patients

The safety and efficacy of 0.03% and 0.1% tacrolimus ointment for the treatment of atopic dermatitis were evaluated in a 12-week, randomized, double-blind, vehicle-controlled study of 351 children 2 to 15 years of age with moderate to severe atopic dermatitis. The mean age of patients was 6.1 years. A total of 61.5% of patients had severe atopic dermatitis at baseline. The mean percentage of body surface area affected was 47.7%, and 83.5% of patients were affected on the head and/or neck. Significantly more patients (P<.001) achieved clinical improvement of 90% or better with 0.03% or 0.1% tacrolimus ointment compared with vehicle. Significant improvements in the signs and symptoms of atopic dermatitis, percent body surface area affected, and the patient's assessment of pruritus were also observed early in treatment and were maintained throughout the study. Adverse events with a statistically significantly greater incidence in the 0.03% tacrolimus ointment treatment group compared with vehicle were limited to the sensation of skin burning, pruritus, varicella, and vesiculobullous rash ("blisters"). Varicella and vesiculobullous rash occurred at a low incidence (<5%). No adverse event occurred at a statistically higher incidence in the 0.1% tacrolimus ointment-treated group compared with vehicle. Tacrolimus ointment was equally safe for younger (2-6 years) and older (7-15 years) children. Both tacrolimus ointment concentrations (0.03% and 0.1%) were safe and significantly more effective than vehicle for the treatment of atopic dermatitis in children.

Atopic dermatitis in 5-6-year-old Swedish children: cumulative incidence, point prevalence, and severity scoring

BACKGROUND

This study aimed to evaluate the cumulative incidence, point prevalence, and severity of atopic dermatitis (AD) in a pediatric population. We also aimed to identify differential diagnoses relevant to AD in this population.

METHODS

Children scheduled for a health visit at 5.5 years of age were selected consecutively during the period October 1997-March 1998 from two cities in southern Sweden (Göteborg and Kristianstad). Schultz Larsen's questionnaire was used to evaluate the cumulative incidence of AD. Clinical examination was performed by dermatologists (A.B. and A.S.) for those children with active eczema. The UK working party's criteria were used for the clinical diagnosis of AD. The SCORAD index was used to evaluate the severity of eczema. This index includes evaluation of extent, intensity, and subjective symptoms to a maximum score of 103 points.

RESULTS

In Göteborg 1219 and in Kristianstad 742 questionnaires were answered regarding 1961 children, 1004 boys and 957 girls. The response rate was 89%. According to the answers to Schultz Larsen's questionnaire, the cumulative incidence of AD in the whole material was 20.7% (406/1961) (CI 95% 18.9-22.5). In Göteborg, 104 of the examined children fulfilled the UK working party's criteria, equivalent to a point prevalence of 8.5% (CI 95% 7.0-10.1). In Kristianstad, the corresponding point prevalence was 11.5% (CI 95% 9.2-13.8). The severity of AD was evaluated in all children with visible eczema. SCORAD evaluation was performed in 155 of the 157 children with visible eczema. The majority of children had mild or moderate eczema; mean value 20.5 (CI 95% 18.7-22.3), median 19.6. Of the 96 children who did not fulfil the criteria of AD, other skin disorders were diagnosed in 51 at the clinical examination. Dry skin was by far the most common differential diagnosis.

CONCLUSIONS

We have used validated protocols to evaluate the cumulative incidence, point prevalence, and severity of AD in a population-based study in southern Sweden The present study, involving a rural and urban pediatric population, shows that AD is common, usually classified as mild or moderate, and seems to increase over time.

Association and linkage of atopic dermatitis with chromosome 13q12-14 and 5q31-33 markers

Atopic dermatitis is a chronic inflammatory skin disease that affects 10-20% of the population. Linkage of atopy, asthma, allergic rhinitis, and total serum IgE levels to several different chromosomal regions have been described extensively, but little is known about the genetic control of atopic dermatitis. We tested for the association and linkage between atopic dermatitis and five chromosomal regions: 5q31-33, 6p21.3, 12q15-24.1, 13q12-31, and 14q11.2/14q32.1-32.3. Marker analysis was performed in two Caucasian populations: (i) 192 unrelated German children with atopic dermatitis and 59 non-atopic children from a German birth cohort study (MAS'90), parental DNA was tested in 77 of 192 children with atopic dermatitis; (ii) 40 Swedish families with at least one family member with atopic dermatitis selected from the International Study of Asthma and Allergy in Children. Evidence for linkage and allelic association for atopic dermatitis was observed for markers on chromosome 13q12-14 and 5q31-33.

Clinical aspects of atopic dermatitis

Atopic dermatitis (AD), or atopic eczema, is the most common, chronic inflammatory disease among children in industrialized countries. We still lack knowledge of its pathophysiology and in particular the role of allergy as both an eliciting factor for disease expression and for disease activity. This article describes the clinical symptoms of the disease and its qualitatively different aspects. AD cannot be understood as being induced by one factor only, e.g. allergy, and this is important when planning treatment strategies. It is also important to realize the very wide range of disease intensity: from subclinical, or latent AD, in which only a few symptoms are present and thus which prevents a clear diagnosis of AD, to its most severe forms including erythroderma. It's unknown aetiology, the wide range in symptomatology, and the fluctuating course (including the many eliciting factors) form the background for our diagnostic and therapeutic difficulties of atopic eczema. AD is prevalent in childhood, but the atopic trait continues, not only for later respiratory allergies, but also for skin diseases in adulthood (such as AD itself or the frequent irritant contact dermatitis of the hands). A child with an acute and first attack of AD is therefore a challenge to the child, its parents and - certainly - to the doctor. However, after stressing the chronicity of the disease, it is equally important to assure the parents that this disease is, in most cases, controllable through correct treatment and that it has a good prognosis: It is not a 'life sentence', but a controllable disease in an otherwise healthy child.

The prevalence of atopic dermatitis in Oregon schoolchildren

BACKGROUND

Although surveys from many parts of the world have shown that the prevalence of atopic dermatitis (AD) in schoolchildren has increased greatly in the past 40 years, there is no current prevalence information from the United States.

OBJECTIVE

Our objective was to investigate the utility of a recently developed European questionnaire to estimate the prevalence of AD in urban and rural Oregon schoolchildren.

METHODS

The self-administered Schultz-Larsen questionnaire (SLQ) of AD symptoms and history was completed by the parents of a broad socioeconomic and ethnic mix of 5- to 9-year-old schoolchildren from 6 urban and 2 rural elementary schools in Oregon. Validation assessments included comparisons of the questionnaire scores with clinical examination in a group of age-matched children and with specific history components known to correlate with AD.

RESULTS

Data showed a prevalence of 17.2% using standard scoring criteria for the SLQ and with a lower limit of 6.8% according to highly stringent criteria derived from the validation study using dermatologic examination. A single question ("Has a doctor ever said that your child has eczema?") was highly concordant with the questionnaire determination, yielding very high predictive accuracy (91.2%).

CONCLUSION

This study of childhood AD frequency indicates a high prevalence of AD in the United States, comparable to that recently observed from studies in Europe and Japan. (J Am Acad Dermatol 2000;43:649-55.).

Epidemiology of atopic dermatitis

Although research into atopic dermatitis (AD) has been dominated by the study of cells and chemical mechanisms over the last 40 years, the last 7 years has witnessed a respectable growth within the field of AD epidemiology. Significant advances include valid disease definitions that can be used in epidemiological studies, global prevalence studies, and studies which quantify the morbidity and economic cost of the disease. These have all helped to argue the case for more research into AD. Epidemiological studies demonstrating that AD is commoner in wealthier families, linkage with small family size, increased prevalence in migrant groups, and the increasing prevalence of the disease all argue strongly towards an important role for the environment in determining disease expression. Future research gaps include evaluation of gene-environment interactions, better studies of the natural history of AD, and better clinical trials that answer questions that are important to physicians and their patients.

Persimmon leaf extract and astragalin inhibit development of dermatitis and IgE elevation in NC/Nga mice

BACKGROUND

We previously found that persimmon leaf extract contains antiallergic substances that inhibit histamine release by human basophilic cell line KU812 in response to cross-linkage of FcepsilonRI.

OBJECTIVES

The purpose of this study was to identify substances in the persimmon leaf extract that are responsible for the effect and to examine their in vivo effects on the allergic mouse model.

METHODS

HPLC analysis of persimmon leaf extract was done to measure its content. Inhibitory activity of persimmon leaf extract or its major constituent of flavonoids (astragalin) on the histamine release by KU812 cells was examined. To investigate the effects of these substances in vivo, models of passive cutaneous anaphylaxis and atopic dermatitis mice (NC/Nga) were used.

RESULTS

Persimmon leaf extract or astragalin inhibited histamine release from KU812 in response to cross-linkage of FcepsilonRI. Oral intake of both substances dose dependently inhibited passive cutaneous reactions. Moreover, oral administration of these substances to NC/Nga atopic dermatitis-model mice led to a striking suppression of the development of dermatitis, scratching behavior, and serum IgE elevation. Histologic analyses revealed that infiltration of inflammatory cells, especially degranulated mast cells, thickening of the epidermis, and prominent hyperkeratosis, were significantly reduced. Immunologic studies showed that the capacity of spleen T cells to produce both IL-4 and IL-13, but not IFN-gamma, was downregulated by means of oral intake of these substances.

CONCLUSION

This study demonstrates a novel activity of astragalin and the dramatic effect of persimmon leaf extract and astragalin on atopic dermatitis-model mice.

Atopic dermatitis

Atopic dermatitis is a chronic skin disorder. It affects up to 15% of the childhood population in the United States and more than half of these patients into adulthood. A clinical diagnosis is made based on the superficial, inflammatory, erythematous and puritic eruptions. Control of symptoms involves patient and parent education with regard to skin care and avoidance of triggers. Treatment includes corticosteroids, with newer strategies emerging.

Atopic dermatitis: new insights and opportunities for therapeutic intervention

Atopic dermatitis (AD) is a chronic inflammatory skin disease that frequently predates the development of allergic rhinitis or asthma. It is an important skin condition with significant costs and morbidity to patients and their families; the disease affects more than 10% of children. Recent studies have demonstrated the complex interrelationship of genetic, environmental, skin barrier, pharmacologic, psychologic, and immunologic factors that contribute to the development and severity of AD. The current review will examine the cellular and molecular mechanisms that contribute to AD as well as the immunologic triggers involved in its pathogenesis. These insights provide new opportunities for therapeutic intervention in this common skin condition.

Chemokines and allergic disease

Understanding the chemokine network has become one of the great challenges for researchers interested in inflammatory mechanisms and inflammation-based diseases. The complexity and diversity of the system provide not only a daunting task for its comprehension but also numerous opportunities for development of new, targeted therapies. It is now certain that chemokines are involved as important mediators of allergic inflammation; the fine details and scope of their roles are now under investigation. Presumably, because of distinct pressures on the immune systems of people living in different geographic regions, genetic variation of ligands, receptors, and regulatory regions in the network have emerged. Establishing the roles of these polymorphisms in determining disease susceptibility or progression among individuals and in distinct ethnic groups will provide a basis for improved understanding and treatment of allergic diseases.