Nasal smear as a screening test for immediate-type nasal allergy.

From a previous sample of 634 students and school children, 115 subjects were selected for a thorough rhinological examination and allergy work-up in order to assess the value of nasal secretion eosinophilia in screening for immediate-type nasal allergy. Part of the subjects had, in the previous study, been found to have secretion eosinophilia and a history of chronic/allergic rhinitis, part of the subjects had either a secretion eosinophilia or a rhinitis history, and part of them had neither a secretion eosinophilia nor a rhinitis history. A significant correlation was obtained between secretion eosinophilia and allergy. Nasal provocation tests correlated with skin tests in 87%, whereas the correlation between nasal provocation tests and Ige determinations in the serum was poorer. Thickening of the maxillary sinus was, when present, usually attributable to infection and not to allergy. Reasons for "false positive or false negative" smears for eosinophils are discussed.