[Prevention of asthma caused by dust mites]

The house-dust mites are responsible for the majority of allergic asthma. It is currently possible to measure the exposure to their allergens, and this allows for a better guide as to the indications for eviction measures; there is also a more objective appreciation of the efficacy of these measures. A decrease in the relative humidity of the interior of the house effectively hinders the proliferation of the mites. Vacuuming the room, notably the mattress, is not sufficient in the majority of cases to reduce the level of allergenicity of the mites to a tolerable level for the asthmatic patient. Thus, it is necessary to renew the bedding, or to hermetically seal the mattress in a plastic cover. Washing the bedding at a temperature above 55 degrees C will kill the mites. Amongst the chemicals available in the struggle to reduce the mite population, the acaricides lead to an elimination of 65-100% of the mites in a mite culture. Tannic acid, which is a protein de-naturing agent, can reduce the allergenicity of the house-dust. Certain control studies related to the effect of the acaricides demonstrate an improvement in objective and subjective parameters of both asthma and rhinitis due to mites. However, the efficacy of these acaricides, as well as measures to clean up the environment within the house, merit more precise evaluation on the symptomatology, the changes of expiratory flow rates, and finally of broncho-reactivity in patients. It is probable that several preventative measures need to be associated if one wishes to improve the efficacy of the struggle to control the house-dust mites.