Treatment principles of atopic dermatitis

Atopic dermatitis (AD) is today the most common, chronic inflammatory skin disease among children in developed countries. Its cumulative prevalence varies from 20% in northern Europe and the USA to approximately 5% in Mediterranean countries. As a chronic disease it puts a special demand on treatment. There is no curative therapy, but competent guidance on treatment principles can control the disease in most, if not all children. This article summarizes the evidence-based knowledge that relates to the treatment of atopic eczema. It also gives advice and opinions on prophylactic measures as these are the focus of interest from most parents. LEARNING OBJECTIVE: This article should enable you to give advice and guidance to parents of children with AD, including what is necessary for diagnosis, what is of value and importance considering allergies and allergological investigations, allergen exposure, prophylactic measures, diets and indoor environment. Finally, you should be able to explain the diversity of treatment principles for parents.     

Substantiating hazardous exposure to asbestos by examination of pulmonary dust

Summary Substantiation of relevant asbestos risks by microscopic examination sets a lower detection limit at fibres longer than 5 to 10 m and thicker than 0.5 m Such microscopically detectable fibres are, of course, in respect to total quantity the insignificant part of the overall dust burden, but apparently a necessary part of the whole fraction when assessing the relevance of exposure. Until now, no epidemiologically conclusive asbestos risks resulting from occupational exposure have been made known solely with fibre fraction below the microscopic detection limit. Demands for supplementary electromicroscopic examination on the basis of case reports of lung parenchyma damage by fibres of a lower calibre than the microscopic detection limit are, therefore, presently without foundation. The subject examinations reveal that substantiation of asbestos risks with light-optical means, using different methods, provides comparable results. Initially, of course, it is surprising to obtain fluctuations in results of 100000 to 600000 asbestos particles for the same case. However, one must realize that calculations based on intermediate results are responsible for this range of fluctuation, due to the varying degree of asbestos fibre dispersion in the different sections of the lung and, depending on the method of detection used. Interest on the part of everyday occupational medicine and expert opinion is determined by the need to categorize individual cases into different basic classes of risk by referring to relevant morphological facts, such as substantiation of asbestosis or drawing a borderline between persons with occupational risk and those with a non-occupational risk. The subject examinations reveal, using different methods of analysis, equally significant results, which correspond with those published by other authors who used a method which, in terms of expenditure for material and manpower, is also suitable for routine analysis.     

Pleural mesotheliomas and asbestos exposure in the pulp and paper industries: a new risk group identified by linkage of official registers

Analysis of data obtained by linking the 1960 Swedish Census and the Swedish Cancer Registry has demonstrated an increased risk of pleural mesothelioma among pulp and paper workers. The present study was undertaken with the aim of revealing possible environmental risk factors. The work histories of the 25 cases identified earlier were reviewed. "Certain" or "probable" exposure to asbestos was found among 70% of these workers. The study illustrates how linkage of official registers can be used to identify new risk environments and encourage the establishment of preventive measures.     

Low-level exposure to house dust mites stimulates T-cell responses during early childhood independent of atopy

Background The imtnune responses which underlie the expression of allergic symptotns in childhood are believed lo be initiated in infancy and early childhood. The kinetics of this response have hardly been researched. Objective To analyse, in an environment with low house dust mite (HDM) exposure levels, the relationship between house dust mite (HDM)-specific T-cell reactivity as expressed by in vitro proliferation of blood mononuclear cells. Methods The study comprised a prospective analysis of patterns of allergen-specific T-cell reactivity in a cohort of 19 children, from whom blood samples were obtained in the spring during their second and third years of life. Blood mononuclear cell cultures were established in 200 μL AIM-V serum free medium. Crude house dust mite (HDM) and purified Der p 1 and Der p 2 extracts were used at optimal concentrations, i.e. 100μg/mL for HDM and 30μg/mL for the purified allergens. Tetanus toxoid (0.5 μglrnL) and ovalbumin (10 μg/mL) served as positive controls. A clinical diagnosis of allergy was verified with skin-prick tests. Dust samples were collected from a mattress and/or carpet or sofa in homes, day care centres and day care homes. Major mite allergen levels (Der p 1/Der f 1) in dust were analysed by an enzyme linked immunosorbent assay (ELISA). Results Specific T-cell responses were seen in the majority of the children against house dust mite (crude HDM extract. Der p 1 and Der p 2). The levels of the house dust mite allergens Der p 1 and Der f I were low, i.e. < 0.68 μg/g fine dust in the homes of the children and the day care centres that they were attending. This indicates that doses of mite antigen well below the suggested sensitization threshold level of 2 μg/g dust can induce mite-specific T-cell responses in young children. None of them showed clinical reactivity to house dust mites as indicated by negative skin-prick tests. Conclusions The findings suggest that active immunological recognition of environmental allergens and the ensuing initiation of allergen-specific T-cell responses, is a normal part of the ‘education’ of the immune system in early childhood and can occur even at very low exposure levels. Priming per se does not imply clinically significant sensitivity, however.     

Comparative analysis of biological activities of Der p I-derived peptides on Fc epsilon receptor-bearing cells from Dermatophagoides pteronyssinus-sensitive patients.

The ability of four uncoupled synthetic peptides (p52-71, p117-133, p176-187, p188-199) derived from Der p I, a major allergen from the house dust mite Dermatophagoides pteronyssinus (Dpt) to stimulate Fc epsilon R+ cells from Dpt-sensitive patients was comparatively analysed. Each free peptide may specifically stimulate basophils (Fc epsilon RI+ cells) and platelets (Fc epsilon RII+ cells) from patients with significant levels of anti-Der p I IgE antibodies; p52-71 and p117-133 appear the best cell stimulation inducers. Both concentration-dependent biological activities of Der p I-peptide on Fc epsilon R+ cells are enhanced by coupling peptide to a carrier (as human serum albumin). Interestingly each Der p I-sensitive patient tested presents an individual pattern of response to peptide. Thus, from our results it appears that different Der p I sequences could be involved in the immune response to Der p I.     

Effect of intranasal fluticasone proprionate on the immediate and late allergic reaction and nasal hyperreactivity in patients with a house dust mite allergy

Background Patients with perennial allergic rhinitis develop nasal symptoms not only after allergen exposure, but generally also after non-specific stimuli. Objective To evaluate the effect of 2 week's treatment with fluticasone propionate aqueous nasal spray (FPANS) on the nasal clinical response, inflammatory mediators and nasal hyperreactivity. Methods Twenty-four rhinitis patients allergic to house dust mite (HDM). participated in a douhle-blind. placebo-controlled crossover study. After 2 week's treatment with placebo or 200 μg FPANS twice daily, patients were challenged with HDM extract. Symptoms were recorded and nasal lavages were collected for up to 9.5 h after challenge. Nasal hyperreaclivity was determined by histamine challenge 24 h later. Results Because of a carry-over effect for the immediate symptom score, for this variable only the data from the first treatment period were used. FPANS treatment resulted in a significant decrease of nasal symptoms with 70%. 69% and 63% after 100. 1000 and 10000 Biological Units (BU)/mL of HDM extract respectively. Active treatment resulted in a 76% decrease of the late-phase symptoms. FPANS treatment significantly reduced albumin influx after HDM 1000 BU/mL with 62% and tended to reduce tryptase release after HDM 1000 BU ml. (P 0.0629). During the late phase FPANS treatment reduced albumin influx with 67% and eosinophil cationic protein (ECP) release with 83%. No effect of FPANS was seen on histamine levels. FPANS significantly decreased histamine-induced symptom score with 34%, secretion with 32%, and sneezes with 41%. Conclusion FPANS significantly inhibits the immediate and late allergic response, and nasal hyperreactivity, probably by suppressing mast cells and eosinophils in the nasal mucosa.     

Enzyme-Linked Immunosorbent Assay for Determination of Major Excrement Allergens of House Dust Mite Species D. pteronyssinus, D. farinae and D. microceras

Species-specific enzyme-linked immunosorbent assays (ELISA) for major excrement allergens (Dp42, Df6 and Dm6) of D. pteronyssinus, D. farinae and D. microceras in house dust were established, using immunoabsorbed, monospecific rabbit antibodies, coupled to horse radish peroxidase. The limit of detection was 13, 4 and 38 ng/ml, respectively. The coefficient of variation for the entire procedure, including dust sieving (212 micron) and extraction was 5-16% for allergen levels above 1000 ng/g dust. Allergen concentration by ELISA correlated well with the number of mite bodies identified and counted by microscopy in 31 dusts (r = 0.88, 0.86 and 0.82 for combined Dermatophagoides sp., D. pteronyssinus and D. farinae group, resp.) Dermatophagoides allergen was recorded in 21/22 mattress dusts (median: 26,000 ng/g; maximum: 290,000 ng/g). D. pteronyssinus allergen occurred in largest amounts (median 7,500 ng/g) followed by D. microceras (median 650 ng/g) and D. farinae (median 240 ng/g).     

Are house dust mite allergen levels influenced by cold winter weather?

BACKGROUND: Moisture is vitally important for house dust mites and they cannot survive in cold or hot-dry climates. AIMS OF THE STUDY: To investigate the influence of two extraordinarily cold and dry winters in 1995/1996 and 1996/1997 on house dust mite levels in German homes. METHODS: Dust samples were collected between June 1995 and December 2001 on the mattresses of 655 adults and 454 schoolchildren living in five different areas of Germany. We compared house dust mite allergen Dermatophagoides pteronyssinus (Der p 1) levels before and during the winters of 1995/1996 and 1996/1997 with levels after these winters. RESULTS: D. pteronyssinus (Der p 1) levels in samples taken after the cold winters of 1995/1996 and 1996/1997 were approximately two times lower than Der p 1 levels in dust samples collected before or during these respective winters (Geometric means: Erfurt 89 vs 33 ng/g; Hamburg 333 vs 219 ng/g; Bitterfeld, Hettstedt, and Zerbst 296 vs 180 ng/g). Except for Hamburg, the decrease in Der p 1 levels was statistically significant. D. pteronyssinus levels measured in dust samples collected in 2001 (i.e. 3 years after the two cold winters) show a statistically non-significant increase (Geometric means: Erfurt 33 vs 39 ng/g; Hamburg 219 vs 317 ng/g), suggesting that it may take a long time for mite allergen levels to increase again after a sudden decrease. CONCLUSION: We conclude that Der p 1 levels in German mattress dust samples have been approximately reduced by a factor of three to four by the two consecutive cold winters of 1995/1996 and 1996/1997.     

Distribution of house dust mite allergen: comparing house dust mite allergen levels in dust samples collected from different sites on living room floors with smooth coverings

BACKGROUND: The distribution of house dust mite allergen (Der p1) in living rooms with smooth floor coverings, as measured in the middle compared with the border of the floor was investigated. It was hypothesized that activity causes displacement of Der p1, from the middle towards the border. METHODS: Dust samples from the middle and border of 50 floors with smooth coverings were collected and analysed on Der p1 content in a standardized way. RESULTS: The Der p1 exposure expressed as per unit area (ng/m2) showed that border samples contained significantly more Der p1 compared with middle samples (median: 2.57 vs 0.27, respectively, P = 0.023). Presence of pets and presence of more than two inhabitants increased the difference. When expressed as per unit weight of dust (ng/g), significant differences were only detected when comparing Der p1 content of samples collected in households with three or more inhabitants [median: 2 (border) vs 53 (middle), respectively; P = 0.035]. CONCLUSIONS: The Der p1 is unequally distributed on living room floors with smooth coverings, most likely because of displacement of dust from the middle towards the border due to activity. Expression as ng/g of dust and ng/m2 could not obviously be interchangeable.