The Effects of Reducing the Mite Allergen Levels in the Residences of Bronchial Asthmatic Children

Mite allergens in a house are considered to sensitize the residents at levels more than 2μg/g fine dust and may cause bronchial asthma at the level over 10 μg/g. The floor materials were substituted to cork and the bedding to mite-free one, and reduction of mite allergens and improvement of the symptoms and signs of bronchial asthma were observed in two houses where there are children with bronchial asthma. Mite allergens were measured in the houses of the children who have been receiving medical treatments for bronchial asthma. Dust samples were collected from the bedding and flooring of their houses before and after the substitution of the flooring and bedding. Mite allergen level was over 10μg/g fine dust in both houses before substitution. The bedding was changed to allergen free bedding and the flooring was substituted from tatami to cork in both houses. The changes of mite allergens in the house, symptoms of asthma, a peak expiratory flow and eosinophils in peripheral blood of the patients were compared before and afterward. A sharp reduction of mite allergen level was shown after the substitution, and the levels were kept under sensitization risk level (2 μg/g fine dust) thereafter. Feedback from the families showed that cork floors were easy to clean and to be a comfortable substitute. After the substitution of bedding, the allergen levels in the residences decreased to 1 / 84 in Family A and 1/ 215 in Family B at peak levels. Eosinophils in peripheral blood decreased in 3 months from 2,032 to 273 /μl (case A-1), 1498 to 450 /μl (case A-2) and 762 to 321 /μl (case B-1). In B-1 case, peak expiratory flow was also improved after the substitution. It was confirmed that substitution of floor materials and bedding could reduce mite allergens in the house and improve bronchial asthma of the residents.