Partial mattress encasing significantly reduces house dust mite antigen on bed sheet surface: a controlled trial

[Atopic eczema. Spectrum of provocation factors and possibilities for their effective reduction and elimination]

Atopic eczema forms together with extrinsic bronchial asthma and allergic rhinoconjunctivitis the classical atopic triad. Genetic predisposition is the crucial pathogenetic factor. The combination of genetic disposition and provocation factors leads to the clinical appearance of skin disease. In addition to therapy adjusted to the stage of the disease, modern management should include a search for relevant trigger factors and then their avoidance to reduce or even prevent flares of the disease. The spectrum of provocation factors ranges from simple measures such as appropriate clothing up to specific measures such as indoor aeroallergen reduction measures.

Laboratory assessment of the efficiency of encasing materials against house dust mites and their allergens

BACKGROUND

The current recommendation to reduce mite allergen exposure for mite-sensitive individuals is to use allergen-impermeable bed coverings. As these covers are made of various kinds of materials, they vary in quality. The objective of this study was to investigate the efficiency of different covering materials against house dust mites and their allergens in vitro.

METHODS

Four types of materials including (1) plastic cover, (2) polyurethane-coated cover, (3) non-woven covers, (4) tightly woven microfiber covers and a regular cotton bed sheet (as a control) were evaluated using three methods: (i) heat escape method, (ii) Siriraj chamber method and stereomicroscopy, scanning electron microscopy and (iii) enzyme-linked immunosorbent assay (ELISA).

RESULTS

We found that there was a statistically significant difference in allergen permeability among four types of coverings (P < 0.001). In terms of the impermeability to mites and their allergens, plastic- and polyurethane-coated covers were observed to be the best, followed by non-woven, woven and cotton-based bed sheets. A regular cotton-based bed sheet allows a significant amount of leakage of mite allergens. Both woven and non-woven material are efficient barriers against mite allergen in terms of impermeability. However, with regard to mite colonization, non-woven covers have the drawback of mites being able to penetrate and colonize within the fabric fibers. Woven covers are therefore recommended because of their major advantages of not allowing the colonization of mites within the fabric, being easy to clean, and comfortable.

CONCLUSION

The three assessment methods used in this study could be useful as a primary approach to evaluate the quality of covering materials in vitro using both pore size and ability to be colonized by mites on the materials as the key factors.

Providing dust mite-proof covers improves adherence to dust mite control measures in children with mite allergy and asthma

INTRODUCTION

The most critical dust mite avoidance technique for asthmatic children with mite allergy is the use of dust mite-proof bedding covers. Adherence to allergen control measures is poor due to cost. The purpose of this study was to determine whether giving families mite-proof bedding encasings at the time of the diagnosis with mite allergy would improve adherence at a home visit 2 months later.

METHODS

Parents of children (mean age 7.7 years) with asthma and positive skin tests for dust mite were assigned either to an intervention group, which received dust mite covers upon enrollment or a comparison group, which did not. Both groups were instructed in dust mite control measures by a medical provider and told to invest in the covers as part of standard care. Two months after enrollment, parent report and observational measures from each family were obtained during a home visit.

RESULTS

The group provided allergen encasings was found to be significantly more likely to have used the casings at the home visit, t(22) = 2.77, P < 0.05. There were no differences between groups in adherence to other mite control strategies. Parenting stress was significantly related to poorer mite control compliance. The most common reason reported for nonadherence to control measures was cost.

CONCLUSIONS

Providing mite bedding encasings at the time of diagnosis significantly increases compliance at a 2-month home visit. Medicaid and insurance companies should be encouraged to pay for casings as a cost effective measure to improve asthma care in children with mite allergy.

Effect of mattress and pillow encasings on children with asthma and house dust mite allergy

BACKGROUND

House dust mite (HDM) allergy is a frequent cause of allergic asthma in children. Reduction of exposure seems to be the most logical way to treat these patients.

OBJECTIVE

Our aim was to investigate whether mattress and pillow encasings resulted in an effective long-term control of HDM allergen levels, thereby reducing the need for asthma medication in children with asthma and HDM allergy.

METHODS

In a prospective, double-blind, placebo-controlled study 60 children (age range, 6-15 years) with asthma and HDM allergy were randomized to active (allergy control) or placebo mattress and pillow encasings. After a 2-week baseline period, follow-up was performed every 3 months for 1 year. During the entire study period, the dose of inhaled steroids was tapered off to the lowest effective dose according to well-defined criteria.

RESULTS

Fifty-two patients completed the trial, and 5 were excluded, leaving data from 47 children (26 in the active treatment group and 21 in the placebo group) for analysis. A significant perennial reduction in HDM allergen concentrations was seen only for the active treatment group. Also, a significant decrease in the dose of inhaled steroids (mean, 408 to 227 microg/d; P <.001) was found for the active treatment group only, with significant differences between groups after 9 and 12 months. After 1 year, the dose of inhaled steroids was reduced by at least 50% in significantly more children in the active treatment group than in the placebo group (73% vs 24%, P <.01).

CONCLUSION

Encasing of mattresses and pillows resulted in a significant long-term reduction in HDM allergen concentrations in mattresses and in the need for inhaled steroids in children with asthma and HDM allergy.

Effect of mattress encasings on atopic dermatitis outcome measures in a double-blind, placebo-controlled study: the Dutch mite avoidance study

BACKGROUND

House dust mite (HDM) allergen might induce and maintain atopic dermatitis (AD). Reduction of allergen load by applying encasings might improve the clinical symptoms of AD.

OBJECTIVE

We sought to investigate, in a randomized, double-blind, placebo-controlled study, whether reducing HDM allergen levels by using mattress, duvet, and pillow encasings for 12 months will result in improvement in AD symptoms.

METHODS

Patients with AD (8-50 years old and allergic to HDM), having a Leicester sign score (a dermatitis score) of at least 1% extent and a severity score of 6 points or greater, were randomly allocated to an active (n = 45) or a placebo allergen-avoidance group (n = 41). Avoidance measures consisted of applying HDM-impermeable encasings for mattresses, pillows, and duvets for the active treatment group and cotton encasings for the placebo group. Effect on allergen concentrations (Der p 1 and Der p 1 plus Der f 1), Leicester sign score extent and severity, visual analogue scale scores for itching and sleeplessness, intradermal test results, atopy patch test results, total serum IgE levels, anti-Der p 1-specific IgE levels, and total blood eosinophil counts were studied.

RESULTS

The active encasings reduced the Der p 1 allergen concentration in the mattress after 12 months with a factor 2.1 (P =.007) and the Der p 1 plus Der f 1 allergen concentration with a factor of 2.5 (P =.005); no significant change in allergen concentrations in mattresses was seen in the placebo group. Although the decrease in allergen load was significant, no differences in treatment-induced changes were seen between the placebo and active groups.

CONCLUSIONS

Use of HDM-impermeable encasings resulted in a significant decrease in Der p 1 and Der p 1 plus Der f 1 allergen concentrations. However, this reduction in allergen load did not result in significant changes in clinical parameters between the groups. Reduction of allergens in other environments (work, school, and outdoors) might be equally important in improving symptoms of AD.

IgE-mediated asthma and rhinitis I: a role of allergen exposure?

Exposures to airborne protein antigens, aeroallergens, may cause sensitization with production of Th2-dependent antibodies, including IgE. The IgE antibodies and associated cellular responses are responsible for the allergic airway diseases, allergic rhinitis and allergic asthma, which are increasing in societies with Western life style. Aeroallergens may have different potential to sensitize exposed subjects. Thus, there are only a limited number of important groups of aeroallergens, which are those from house dust mites, cockroaches, pets, pollens, and moulds. Allergy follows to a certain extent the pharmacological/toxicological paradigm of dose-response relationship. Unlike effects of pharmacologically and toxicologically active substances, allergens elicit their adverse effects in a two-stage process. In the first stage the immunologically naïve individual is sensitized to the allergen. In the second stage renewed exposure to the allergen elicits the disease response. Also, high concentrations of aeroallergens may induce immunological tolerance. The scientific literature suggests that many environmental factors contribute to the increase in sensitization and development of airway allergies. Nevertheless, the dose-response relationships apply (within certain limits) both to the sensitization itself and to the exacerbation of the diseases. This suggest that exposure reduction may be one of the methods for reduction of risk, in relation to control of the allergic airway diseases.