Diagnosing allergic rhinitis: effectiveness of the physical examination in comparison to conventional skin testing.

OBJECTIVE: To evaluate the effectiveness of physical examination alone in diagnosing nasal allergic patients.
DESIGN: A cross-sectional study of 15 consecutive evaluable patients.
SETTING: A tertiary care otolaryngology clinic at the Jewish General Hospital, McGill University, Montreal.
METHODS: All patients were assessed by three physicians in random order. Each conducted a specific examination, made a clinical impression, and then took a directed history to make a second impression. Both impressions were compared to skin testing. Multivariate regression analyses assessed the linear relationships of both examination and history variables to impressions and skin testing results. Fleiss kappa tests assessed interrater reliabilities. MAIN OUTCOME MEASURES: Accuracy in diagnosing allergic rhinitis by examination alone and inter-rater reliability in this diagnosis.
RESULTS: When comparing physical examination variables to history variables relative to the second impression, history variables had a stronger relationship (R²  =  .90 vs .52). This was also true when comparing both sets of variables to skin testing (R²  =  .81 vs .60). The interrater reliability of physical examination variables was poorer than that of the history variables (.377 and .494, respectively). Taking all physicians, the average sensitivity, specificity, positive predictive value, and negative predictive value of the history impression were all higher than those of the examination impression.
CONCLUSION: Physical examination alone yields unreliable and inconsistent results in diagnosing allergic rhinitis. This is likely secondary to the relative subjectivity involved in evaluating the nasal cavity. Adding a history to the examination is essential to increase diagnostic accuracy.