Eosinophilia in nasal secretions compared to skin prick test and nasal challenge test in the diagnosis of nasal allergy.

This study was aimed to assess the usefulness of eosinophilia measurements in nasal smears (ENS) in the diagnosis of nasal allergy. Nasal smears were taken from 84 patients with histories suggestive of allergic rhinitis. The smears were stained by the Giemsa method and examined by light microscopy. Positive results were demonstrated in 69.2% of the samples. All the 84 patients also had a skin prick test (SPT); the perceniitage of correct correlation between ENS and SPT was 71.4%. Forty-two patients underwent nasal challenge test (NCT) and the percentage of correct correlation between ENS and NCT was 69%. Nine patients had negative SPT, but positive ENS. All were nasally challenged with 4 proving positive. This leaves 5 individuals (5.9% of the 84 studied) in the non-allergic rhinitis with eosinophilia category. Based on these findings, it is suggested that the assessment of eosinophils in nasal smears should be given more relevance and be more commonly used in the diagnosis of nasal allergy.