Epidemiology of asthma and allergic rhinitis in a total community, Tecumseh, Michigan: IV. Natural history

The incidence and remission of allergic rhinitis and asthma were studied in 6,563 residents of Tecumseh, Michigan, who were examined on two occasions separated by an average interval of 4 years. The 4 year incidence of probable allergic rhinitis was 2 per cent for males and females, and the 4 year incidence of probable asthma was 1 per cent for both sexes. During this time interval the incidence of allergic rhinitis among males and females who previously had asthma was 3 per cent and 5 per cent, respectively. The incidence of asthma in persons who previously had allergic rhinitis was 1 per cent in males and 3 per cent in females. Remission occured in approximately 20 per cent of persons with asthma and 8 per cent with allergic rhinitis over a 2 year period. Either disease was as likely to remit if the other disease was present or not. Allergic rhinitis was more likely to remit when the duration was shorter than 5 years, while asthma remissions were not clearly influenced by duration. Persons with perennial allergic rhinitis were less likely to remit than those with seasonal symptoms.