A sensitisation to allergens has not always a clinical relevance. Therefore, the history has an uppermost importance for defining the relevance of a sensitisation. In contrast to the history in seasonal rhino-conjunctivitis, which causes typical complains in a restricted time period patients with house dust mite allergy seem to have less defined complaints. To define the most relevant symptoms of this frequent allergy, we evaluated 35 patients with clearly defined house dust mite allergy by a questionnaire and evaluated the same questionnaire also in a control group of 18 patients without sensitisation or asthma. The symptoms described in the patient group confirm that symptoms of house dust mite allergy are frequently not related to a direct allergen exposure. Some patients complained about itchy red eyes in the morning, but the majority of symptoms occurred independent from allergen exposure. These are blocked nose as well as exercise induced asthma. These symptoms are present all year around and are not only restricted to mite exposed areas. They are probably related to the underling eosinophilic inflammation. Thus exercise induced asthma and blocked nose are symptoms, which may indicate a mite allergy, particular in younger patients.

Many patients complain about hyperreactivity of the skin or mucosal membranes, whereby rather harmless "triggers" lead to exaggerated reactions like running nose, bronchospasm, urticaria, etc. Most of these hyperreactivities have an underlying inflammation. It is important not to focus only on the triggers, but to look for the agent causing the inflammation and to avoid/treat it: elimination of the cause also eliminates the hyperreactivity. Four examples are presented where this cause--trigger model of hyperreactivity is illustrated (exercise induced asthma, pollen associated food allergy, flare-up reactions in drug allergy and hyperreactivity in chronic urticaria).