Flowers and other trigger factors in asthma and rhinitis--an inquiry study.

Six hundred and eighty adult patients with asthma and/or rhinitis were questioned about symptoms elicited by 46 different flowers and 10 common non-specific environmental trigger factors listed in a questionnaire. Flowers or birch twigs were reported to elicit symptoms in 79% of the patients, somewhat more often in rhinitis than in asthma patients, and caused symptoms as often in non-atopics as in atopics. Birch twig and marguerite most frequently induced symptoms, followed by strongly smelling flowers such as hyacinth, lilac, and lily of the valley. Unspecific irritants caused symptoms in 98% of the asthmatics and in 67% of patients with rhinitis. Tobacco smoke and perfumes were the most important troublemakers. A significant positive correlation was found for elicitation of symptoms from flowers and from certain non-specific irritants. It is concluded that non-specific hyperreactivity as well as reaginic hypersensitivity are the mechanisms involved when birch twigs and flowers elicit symptoms.