[Allergic rhinitis. Pathophysiology, diagnosis, differential diagnosis and therapy].

Allergic diseases caused by inhalant allergens are considered to be a major health problem. Allergic rhinitis, now affecting about 15% of the population, represents an inflammatory reaction, that may lead to asthma and chronic sinusitis as subsequent problems. Diagnosis should be based on a step-by-step concept, that also takes the clinical relevance of sensibilisations and other forms of nasal hyperreactivity into account. The aims of therapy are to limit the inflammatory reaction and to restore patient's quality of life. To achieve this goal, avoidance measures, immunotherapy and antiallergic drugs are currently used. The indication for and the performance of an immunotherapy demands special knowledge, and also the different drug activities and possible side effects should be thoroughly considered.