VALIDATION OF A RHINITIS SYMPTOM QUESTIONNAIRE (ISAAC CORE QUESTIONS)IN A POPULATION OF SWISS SCHOOL-CHILDREN VISITING THE SCHOOL-HEALTH SERVICES

The primary aim of the study was to assess the validity of the ISAAC c ore questions on rhinitis in a population of Swiss school children by comparing them to skin prick test results. Second, the positive predic tive value in detecting atopy among children with rhinitis symptoms wa s determined, Third, agreement between parental reports of hay fever a nd rhinitis symptoms was evaluated, since earlier Swiss prevalence sur veys had exclusively relied on reported hay fever. Material and method s: Two thousand nine hundred and fifty-four (81.2%) parents of 7, 10 a nd 14-year old children filled in an exhaustive questionnaire which in cluded the ISAAC core questions on rhinitis. Two thousand one hundred and twenty children also underwent skin prick testing against six comm on aeroallergens (grass mixture, birch, mugwort, D. pteronyssinus, cat and dog dander). The analysis is restricted to children with both que stionnaire data and skin prick test results. Results: Sensitization to any allergen was most strongly associated with reported hay fever (OR = 5.7, 95% CI 4.4-7.4), nose problems accompanied by itchy-watery eye s (OR = 4.4, 95% CI: 3.3-5.7), symptoms occurring only during pollen s eason (March through September) (OR = 4.9, 95% CI: 3.6-6.5) and a comb ination of these latter two symptoms (OR = 5.8, 95% CI: 4.1-8.1). The association was stronger for a sensitization to outdoor allergens than for indoor allergens, The specificity of the various questions was hi gh, ranging from 77.5% to 97.6%, but the sensitivity was low (2.6% to 42.7%). The positive predictive value for atopy among children with sy mptoms was 63% for sneezing accompanied by itchy-watery eyes, 67% for symptoms occurring only during the pollen season and 70% for reported hay fever, However, agreement between reported rhinitis symptoms and h ay fever was only moderate. About one third of the children with sympt oms indicative of seasonal rhinitis did not report the label ''hay fev er''. Conclusions: We conclude from our analyses that the ISAAC core q uestions on rhinitis are highly specific and therefore useful in exclu ding atopy. In addition they have a high positive predictive value in detecting atopy among children with symptoms, but they are not helpful for detecting atopy in a general population of children (low sensitiv ity). To monitor time trends in the prevalence of allergic rhinitis in Switzerland, questions on rhinitis symptoms as well as on the diagnos tic label ''hay fever'' have to be included in a questionnaire because they contain complementary information since under-diagnosis of aller gic rhinitis is common.