[Extrinsic-allergic asthma--principles, diagnosis, therapy, danger of disability]

In Germany approximately 5 per cent of the population suffer from asthma. The disease is characterized by nonspecific airway hyperresponsiveness to various stimuli, leading to airways obstruction. In the majority of cases sensitizations to inhaled or food allergens are revealed by skin tests and/or in-vitro tests (RAST) ("extrinsic" asthma). Due to an allergen-induced increase of non-specific airway hyperresponsiveness allergencontacts favor asthmatic symptoms after non-specific stimuli, such as cold air or exercise. Therefore diagnostic measures in asthma should include allergic history and standard allergen skin tests in each case. Nonspecific stimuli often play a predominant role among the causes of acute airways obstruction, depending on the degree of nonspecific hyperresponsiveness. Other cases of asthma are characterized by the absence of senzitizations ("intrinsic" asthma). Usually, the symptomatology of these cases is more severe than in extrinsic asthma. In most cases of allergic asthma prognosis is favourable, in contrast to chronic obstructive bronchitis and/or emphysema. The therapeutic approach consists of allergen avoidance and hyposensitization, if feasible, and of a combination of bronchodilating and antiinflammatory drugs. A number of work places has to be avoided. Drug treatment should aim at reducing airways hyperresponsiveness and absence of asthmatic symptoms, requiring (inhaled) steroids in most cases. Other therapeutic principles have to be considered, such as allergen avoidance, cessation of cigarette smoking, change of work place, choice of favourable climates during holidays, and hyposensitisation.