The Indoor Level of House Dust Mite Allergen Is Associated with Severity of Atopic Dermatitis in Children

We attempted to investigate the correlation between the severity of atopic dermatitis (AD) in children and the indoor level of house dust mite (HDM) allergens. Ninety-five patients (31.1 +/- 19.5 months of age) with AD were enrolled in this study, and serum specific IgE against Dermatophagoides pteronyssinus and D. farinae was measured. The severity of AD was assessed using the visual analogue scale on the same day of house dust collection. Living rooms and mattresses where the child usually slept were vacuumed for 2 minutes and concentrations of Der f 1 were measured by enzyme-linked immunosorbent assay. The skin symptoms were more severe in patients with Der f 1 concentrations in living room > 2 microg/g dust than < or = 2 microg/g dust (P = 0.018). This difference was noted in AD patients without sensitization to HDM (P = 0.004), but not in patients with sensitization. There was no difference in symptom severity according to Der f 1 concentrations in mattresses (P = 0.062). The severity of skin symptoms is associated with indoor concentrations of HDM in children with AD, and it is likely to act as nonspecific irritants as well as allergens in AD skin lesions.

The hammock: a reservoir of allergens

INTRODUCTION: Asthma affects approximately 10 percent of the world's population. Sensitization to allergens is an important risk factor, and exposure to allergens is associated with disease severity. METHODS: We performed skin tests to evaluate allergen sensitization to mites, cockroaches, cats, dogs, and molds in 73 asthmatic patients. Enzyme Linked Immunosorbent Assay was used to assay the mite and cockroach allergens found in dust from the bedding, hammocks, bedroom floors, living rooms, and kitchens of 29 patients and 14 controls. RESULTS: Fifty patients (68.5 percent) had positive skin test responses. There were positive responses to D. pteronyssinus (52.0 percent), B. tropicalis (53.4 percent), T. putrescentiae (15.0 percent), E. maynei (12.3 percent), L. destructor (8.2 percent), B. germanica (20.5 percent), P. americana (21.9 percent), Felis catus (10.9 percent), C. herbarium (2.7 percent), A. alternata (4.1 percent), and P. notatun (1.3 percent). The exposure to mite and cockroach allergens was similar in the patients and the controls. The Dermatophagoides pteronyssinus Group 1 levels were highest in the beds and hammocks. The Blattella germanica Group 1 levels were highest in the kitchens, living rooms and hammocks. DISCUSSION: The positive skin tests to mites, cockroaches and cats were consistent with previous studies. D pteronyssinus was the most prevalent home dust mite, and hammocks were a source of allergens. To improve asthma prophylaxis, it is important to determine its association with mite allergen exposure in hammocks.

Effect of an Air Cleaner with Electrostatic Filter on the Removal of Airborne House Dust Mite Allergens

PURPOSE: The effects of air cleaners on the removal of airborne indoor allergens, especially house dust mites (HDM), are still controversial. The objective of this study is to evaluate the effect of an air cleaner with an electrostatic filter on the removal of airborne mite allergens. MATERIALS AND METHODS: A dried HDM culture medium that contained mite body particles and excretions was dispersed in a chamber equipped with an electrostatic air cleaner. The number of airborne particles was recorded continuously by a dust spectrometer for 60 minutes. Airborne particles in the chamber were collected on a sampling filter at a flow rate of 10 L/min and the Der f 1 concentration in the filter extracts was measured by two-site ELISA. RESULTS: The air cleaner efficiently removed airborne HDM particles. The air cleaner removed airborne HDM particles (size 2-12.5 microm) 11.4 +/- 2.9 fold (cleaner operating for 15 minutes), 5.4 +/- 0.7 fold (cleaner operating for 30 minutes), and 2.4 +/- 0.2 fold (cleaner operating for 60 minutes) more than the removal of HDM particles by natural settle down. Removal kinetics differed according to the particle size of the airborne particles. The air cleaner decreased the concentration of Der f 1 in the extraction of airborne particles collected on the air sampling filter by 60.3%. CONCLUSION: The electrostatic air cleaner can remove airborne HDM allergens and may be useful as a supplementary environmental control tool for HDM sensitized respiratory allergic patients.

Diversidade da exposição alergênica: implicações na obtenção da eficácia do controle ambiental: [revisão] / Diversity of allergen exposure: implications for the efficacy of environmental control: [review]

As doenças alérgicas, como a asma, rinite, conjuntivite alérgica e a dermatite atópica têm apresentado um aumento na sua prevalência nas últimas décadas. A relação entre exposição alergênica, sensibilização atópica e desenvolvimento de doenças alérgicas são amplamente descrita na literatura. OBJETIVO: Discutir a dificuldade no controle ambiental da exposição alergênica como parte do tratamento das doenças alérgicas. MÉTODOS: Analisar trabalhos de exposição alergênica realizados com metodologia similar na região central do Brasil, incluindo casas, hotéis, cinemas, carros, táxis, ônibus e transporte escolar. RESULTADOS: Níveis elevados dos alérgenos do grupo 1 de Dermatophagoides pteronyssinus (Der p 1) e de D. farinae (Der f 1), capazes de causar sensibilização e exacerbação de sintomas foram encontrados na maioria dos ambientes estudados em uma larga proporção das amostras, enquanto os alérgenos de animais domésticos atingiram maiores níveis em carros e veículos de transporte escolar. CONCLUSÃO: A diversidade da exposição alergênica mostra a necessidade de uma compreensão da doença alérgica pelos pacientes e familiares, e que as medidas de controle do ambiente doméstico fazem parte de uma estratégia global do tratamento das doenças alérgicas, uma vez que os indivíduos vivem em uma sociedade e não isoladas no interior de seus domicílios.

The prevalence of allergic diseases such as asthma, rhinitis, allergic conjunctivitis and atopic dermatitis has increased in the last decades. The relationship between allergen exposure, atopic sensitization and development of allergic diseases is widely described in the literature. AIM: To evaluate measures for reducing allergen exposure as part of the treatment of allergic diseases. METHODS: An analysis was made of previous studies on allergen exposure done with a similar methodology in the central region of Brazil; the study included homes, hotels, cinemas, cars, taxis, buses and scholar transportation. RESULTS: High levels of Der p 1 and Der f 1 mite allergens were found in a large proportion of the sample in most of the environments included in those studies; there were higher levels of pet allergens in cars and school transportation vehicles. CONCLUSION: The diversity of allergen exposure demonstrates the need for education about allergic diseases for patients and their families, as well as measures of reducing allergens in homes. This should be part of a global strategy of the management of allergic diseases, given that individuals live in society, not only in their houses.

Effect of Bedding Control on Amount of House Dust Mite Allergens, Asthma Symptoms, and Peak Expiratory Flow Rate

This quasi-experimental study was designed to investigate the effect of bedding control on the amount of house dust mite (HDM) allergens, asthma symptoms, and peak expiratory flow rate (PEFR) in asthmatics sensitive to HDMs. The subjects in the study were drawn from patients receiving treatment at the allergy clinics of three university-affiliated hospitals in Seoul. Forty-two patients without prior practice of the bedding control used in this study were selected. They commonly showed bronchial asthma caused by HDMs, and exhibited strong positive points (more than 3 points) in skin prick test (D. farinae, D. pteronyssinus), and positive response in both fluoro-allergosorbent test (FAST), and PC20 methacholine test. Of the subjects, alternatively, 22 were assigned to the experimental group and 20 to control group. Bedding control consisted of the use of outer cotton covers, boiling them for 10 minutes fortnightly, and disinfecting bedding by sunlight fortnightly. The experimental group was under bedding control for 4 weeks. The data were collected from October 2000 to January 2001. The results were as follows: 1. After bedding control, the total amount of HDM allergens decreased significantly in the experimental group. However there was no significant difference in the decrease of the amount of HDM allergens between the two groups. 2. Of the asthma symptoms, there was significant difference only in the decrease of the frequency of dyspnea, and in the increase of sleeping disturbance between the two groups after bedding control. 3. After bedding control, PEFR increased in the experimental group whereas it decreased in the control group. However, neither change was significant. The above findings indicate that bedding control improved several asthma symptoms in asthmatics sensitive to HDMs. Accordingly, we suggest that bedding control is adopted as a useful nursing intervention in the field.