Investigating nasal cytology as a potential tool for diagnosing occupational rhinitis in woodworkers

Background: Our primary endpoint was to use nasal cytology to compare woodworkers with unexposed subjects to see if wood dust exposure correlates with specific patterns of inflammatory or infectious rhinitis. A secondary endpoint was to identify any differences in the exposed group's nasal symptoms or nasal cytology by years of exposure or personal exposure levels. Methods: Ninety-two woodworkers and 90 controls were assessed using a questionnaire and nasal cytology (on nasal mucosa obtained by scraping). Wood dust exposure was investigated using personal sampling methods. Results: Woodworkers reported significantly more nasal symptoms than controls (p < 0.00001). The woodworkers' nasal smears revealed more neutrophils (p = 0.001) and significantly higher mean neutrophil scores (p = 0.001) than control smears. Lymphocytes were also found more often in the woodworkers' rhinocytograms (statistical trend, p = 0.06). Neutrophilic rhinitis was diagnosed more frequently in the exposed workers than in controls (chi-square = 5.97, p < 0.05). Woodworkers with lymphocytes in their nasal smears had been exposed to wood dust for longer periods of time (statistical trend; p = 0.06). No differences in nasal symptoms or cell counts emerged when woodworkers were stratified by levels of personal exposure. Conclusion: Nasal cytology should be further investigated in woodworkers before considering it a screening method for identifying woodworkers with chronic inflammatory rhinitis.