Prevalence and prediction of allergic rhinitis using questionnaire and nasal smear examination in schoolchildren.
Allergic rhinitis is a common condition among schoolchildren. However, little is known about the prevalence of nasal eosinophilia. We investigated the prevalence of rhinitis via questionnaire and nasal smears for eosinophils. The questionnaire was administered in 1992 and 1995. Complete responses were obtained from 1044 and 431 schoolchildren, respectively, of whom 26.5% and 22.5% claimed to have nasal symptoms. Nasal smears were taken in 1992, 1993 and 1994, and 415, 285 and 384 samples were collected, respectively. Positive eosinophilia were seen in 39.8%, 35.1% and 35.9% children in 1992, 1993 and 1994, respectively. In 1992, we utilized both questionnaire and nasal smears simultaneously to evaluate 415 schoolchildren. Of 415 schoolchildren, 72 (17.3%) had both nasal symptoms and nasal eosinophilia. Interestingly, those who showed positive eosinophilia in 1992, especially those who had eosinophilia with nasal symptoms, had significantly higher incidence of nasal symptoms three years later in 1995 than those who showed negative eosinophilia in 1992. These results suggest that nasal eosinophilia in schoolchildren are associated with subsequent nasal symptoms, and that nasal smear examination may be a potentially valuable test to predict prolonged or recurrent allergic rhinitis.