Patterns of nasal eosinophilia in allergy clinic patients as determined by swab and curette sampling

The presence of eosinophils in nasal secretions often characterizes inflammatory disease in the nose and paranasal sinuses. This study analyzed differential associations between various clinical parameters and the presence of nasal eosinophilia in mucosal specimens obtained by two sampling methods (swab and curette-probe). Nasal mucosal secretions were obtained in patients attending an adult allergy clinic using both sampling methods for each patient. The presence of eosinophilia as determined by both methods had significant associations with 1) nasal mucosal pallor, 2) younger age, and 3) the presence of basophilic cells. To examine diagnostic characteristics of the two sampling methods of determining eosinophilia as a characteristic of allergic rhinitis, receiver operating characteristic (ROC) curves were evaluated for patients categorized as having allergic rhinitis on the basis of elevated aero-allergen specific IgE, and rhinitis based on either a) significant nasal mucosal appearance abnormalities, or b) a referring physician's diagnosis of rhinitis. The curette-probe determined nasal eosinophil quantitations had greater areas under the ROC curves when rhinitis was defined on the basis of mucosal appearance. On the other hand, the swab determined eosinophil quantitations had greater ROC curve areas when rhinitis was defined on the basis of referring diagnosis. In summary, nasal eosinophilia determined by curette or swab sampling has differences in strengths of their clinical associations.