Eczema, atopy and allergen exposure in adults: a population-based study

BACKGROUND: There are few published studies on geographical variation in prevalence of eczema in adults or its association with recognised risk factors for allergic disease. OBJECTIVE: To describe the geographical variation in prevalence of eczema in adults, assess the associations with sociodemographic risk factors, serum-specific IgE and IgG, and exposure to allergen. METHODS: A community-based sample of 8206 adults aged 27-56 years, in 25 European centres and Portland, USA, provided questionnaire information on symptoms of eczema. Serum-specific IgE to house dust mite (HDM), cat, grass and Cladosporium, and IgG and IgG4 to HDM and cat were measured. Mattress levels of mite and cat allergen were assessed. RESULTS: Overall prevalence of eczema was 7.1% (range between countries of 2.2-17.6%). Eczema was associated with female gender [odds ratio (OR) 1.25; 95% confidence interval (CI) (1.01-1.55)], family history of atopic disease (OR 1.43; 95% CI 1.18-1.74), IgE sensitization to at least one allergen (OR 1.50; 95% CI 1.19-1.90), particularly Cladosporium (OR 3.65; 95% CI 1.81-7.37), and total IgE. Eczema was negatively associated with age and no clear associations were observed with sibship size, mattress mite and cat allergen levels or with cat and HDM-specific IgG or IgG4. CONCLUSIONS: There is geographical variation in the prevalence of eczema in adults both within and between countries. Although the disease is associated with IgE sensitization, in this study it was not related to mattress mite or cat allergen levels.     

Enhanced Platelet Activation in Patients with Atopic Eczema/Dermatitis Syndrome

Data gathered prove that circulating platelets are activated upon human allergic inflammation, partly as a result of direct IgE-mediated process. It has been indicated that platelets may contribute to pathogenesis of atopic eczema/dermatitis syndrome (AEDS). Authors of the recent study have investigated systemic platelet activation in patients with AEDS on the basis of blood level of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4), which are recognized markers of platelet activation, also belonging to C-X-C chemokine family. Plasma levels of beta-TG and PF4 were measured by enzyme-linked immunoassay (ELISA) in 18 AEDS patients with moderate disease activity and 23 healthy, nonatopic individuals. No differences in peripheral platelet count of the two groups were noted. Only four (33.3%) AEDS patients represented beta-TG and PF4 within the control range; plasma beta-TG and PF4 were significantly increased (p < 0.001) in the AEDS group compared as a whole with the control subjects. No association between circulating concentrations of beta-TG or PF4 and total IgE levels in AEDS patients was proved. The results suggest that some patients with AEDS may have enhanced blood platelet activity as expressed by beta-TG and PF4 level.     

Low prevalence of the intrinsic form of atopic dermatitis among adult patients

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disease commonly associated with respiratory allergies such as rhinitis and asthma, and a high serum level of IgE. In contrast to the 'classic' IgE-mediated allergic (extrinsic) form of AD, approximately 20% of the patients are reported to show normal IgE levels, lack of sensitizations towards environmental allergens, and absence of associated respiratory allergies. Accordingly, these patients are assigned to a nonallergic (intrinsic) form of the disease. OBJECTIVES: In order to define these two forms of AD more closely, 259 adult patients with AD were investigated. RESULTS: After a thorough diagnostic workup there were 18 patients (6.9%), who fulfilled the criteria of intrinsic AD. After follow-up, four additional patients had developed respiratory allergies or IgE-mediated sensitizations resulting in an overall proportion for intrinsic AD of 5.4%. CONCLUSIONS: Based on these figures the nature and relevance of the intrinsic form of AD deserves further evaluation.     

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 Å.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.     

Circulating Levels of Urokinase-Type Plasminogen Activator (uPA) and its Soluble Receptor (suPAR) in Patients with Atopic Eczema/Dermatitis Syndrome

Accumulating evidence has indicated that different immune and inflammatory processes may be accompanied by up-regulation of the uPA/uPAR system. Moreover, it has been suggested that the fibrinolytic system participates actively in immune-mediated skin disorders, including atopic eczema/dermatitis syndrome (AEDS). To study a possible role of such uPA/uPAR system in AEDS, we investigated circulating levels of uPA and suPAR in patients at different clinical stages of AEDS. Levels of u-PA and suPAR were measured by enzyme-linked immunoassay in plasma from 13 patients (five females and eight males; median age 27 years) with moderate AEDS, eight patients (three females and five males; median age 25.5 years) with severe AEDS, and 18 age- and sex-matched healthy subjects. Plasma levels of uPA and suPAR in AEDS patients did not differ significantly when compared with those in healthy subjects. Moreover, we failed to observe any significant differences in levels of these components between patients with moderate and severe AEDS and the controls. It seems that plasma levels of uPA and suPAR are similar in patients at the different stages of AEDS and the healthy subjects. Moreover, these data suggest that the release of uPA and its soluble receptor into the bloodstream is not increased in the course of complex immune-mediated processes associated with AEDS.     

Immunoglobulin E- (IgE) and non-IgE-mediated reactions in the pathogenesis of atopic eczema/dermatitis syndrome (AEDS)

AEDS is a chronic, relapsing, highly pruritic inflammatory skin disease that commonly begins in childhood. Two forms of this disorder exist, i.e. an allergic (extrinsic) form and a nonallergic (intrinsic) form. There are clear genetic, humoral and cellular differences between the allergic and nonallergic forms of AEDS. The allergic variants express local IgE production in affected tissue and both allergic and nonallergic triggers play a major role in the expression of disease. The role of allergens is very important in the immunopathogenesis of AEDS. Nonimmunological triggers play a secondary modulatory role often hampering treatment effort and optimal response to therapeutic efforts.     

Atopic dermatitis, extrinsic atopic dermatitis and the hygiene hypothesis: results from a cross-sectional study

BACKGROUND: Atopic Dermatitis (AD), hayfever and asthma are commonly summarized as atopic diseases. The spatial distribution of AD differs from that of asthma and hayfever, suggesting that AD might follow a different risk pattern than these diseases. AD can be differentiated into an allergic extrinsic form (EAD) and a non-allergic intrinsic form (IAD). Only EAD might follow the distribution and risk pattern that have been ascribed to asthma and hayfever. OBJECTIVE: To investigate the distribution and risk factor profile of AD and EAD focusing on environmental factors relating to the hygiene hypothesis. METHODS: Population-based cross-sectional study on 12,601 children aged 5-7 and 9-11 years from Dresden (Eastern Germany) and Munich (Western Germany). Information was obtained by International Study of Asthma and Allergic Childhood questionnaires, dermatological examinations and skin prick testing. AD-diagnosis ever, current AD-symptoms and visible eczema were investigated with their respective extrinsic forms. RESULTS: Maternal and paternal history of AD were equally strong determinants of the child's AD status. Factors related to the hygiene hypothesis like day-care attendance and number of older siblings were not associated with a decreased risk of AD. The proportion of EAD within AD was higher in Eastern than in Western Germany. The determinants of the diseases appeared to be similar for both EAD and IAD. CONCLUSIONS: There was no evidence of the hygiene hypothesis holding true for AD or EAD. AD might be a separate entity than respiratory atopic diseases. Little is known about the risk factors of AD and factors different from those of respiratory allergic diseases should be considered in future research.     

The prevalence of atopic dermatitis beyond childhood: A systematic review and meta‐analysis of longitudinal studies

Background

There are sparse and conflicting data regarding the long‐term clinical course of atopic dermatitis (AD). Although often described as a childhood disease, newer population‐based estimates suggest the prevalence of pediatric and adult disease may be similar.

Methods

Our objective was to determine whether there is a decline in the prevalence of AD in population‐based cohorts of patients followed longitudinally beyond childhood. We conducted a systematic review and meta‐analysis including studies assessing AD prevalence across 3 or more points in time. The primary outcome was weighted overall risk difference (percentage decrease in AD prevalence).

Results

Of 2080 references reviewed, 7 studies with 13 515 participants were included. Participants were assessed at 3‐6 time points, ranging from age 3 months to 26 years. The percentage decrease in prevalence after age 12 was 1%, which was not significantly different from zero (95% confidence interval ?2%‐5%). Similar results were found with other age cut‐offs.

Conclusion

The prevalence of AD in longitudinal birth cohort studies is similar in childhood and adolescence/early adulthood.

     

Atopic dermatitis: a disease of altered skin barrier and immune dysregulation

Atopic dermatitis (AD) is an important chronic or relapsing inflammatory skin disease that often precedes asthma and allergic disorders. New insights into the genetics and pathophysiology of AD point to an important role of structural abnormalities in the epidermis as well as immune dysregulation not only for this skin disease but also for the development of asthma and allergies. Patients with AD have a unique predisposition to colonization or infection by microbial organisms, most notably Staphylococcus aureus and herpes simplex virus. Measures directed at healing and protecting the skin barrier and addressing the immune dysregulation are essential in the treatment of patients with AD, and early intervention may improve outcomes for both the skin disease as well as other target organs.