[Environmental allergens and allergic diseases].

Prevalence of allergic diseases in Japan has been increasing these 30 years. About 3%/5% of adult/ child general population are suffering from bronchial asthma these days. Housedust-mite, pollen, fungi and food have been identified as causative allergen. But recent change of life style in Japan is thought as the most important cause of increase of allergic diseases, such as change from life in wooden houses to concrete buildings. A full-day air-conditioning is comfortable not only for residents but also for microorganisms such as mite and fungi. Therefore, chance to expose to these allergens has been increasing. It is well-known that mite allergen is the most important causative allergen of bronchial asthma. Allergen analysis made us possible to measure the amount of allergen contents in our environment. It is known that 2 micrograms of Der 1 allergen of mite per 1 g of dust is enough to sensitize the host and 10 micrograms per 1 g dust can induce asthma attack. As mite allergens are rich in a sleeping mattress, asthma patients with mite allergy sometimes get asthma attack during sleeping at night. Pet dander such as cat and hamster are also popular causative allergens of asthma. About 30% of asthma patients show positive immediate skin response to these allergens. Releasing the pet from patients' home sometimes brought immediate relief from their symptoms.