Nasal scraping in wood dust workers to screen nasal inflammation

Introduction
The aim of the study was to investigate the relationships between wood dust exposure and nasal cytological alterations.

Methods
73 subjects occupationally exposed to wood dust and 74 unexposed were evaluated with anterior rhinoscopy. A nasal cytological sample of the inferior turbinate was taken by scraping to study the presence of inflammatory cells (neutrophils, eosinophils, mast cells and lymphocytes), bacteria and fungi. Wood dust personal exposure was performed by IOM selector connected to a SKC sampler operating at a flow rate of 2 l/min.

Results
A significant increase in neutrophils and lymphocytes was detected in exposed compared to unexposed subjects (neutrophils: 70.7% vs 40.5%; lymphocytes: 18.7% vs 5.4%). Based on a semiquantitative reading of the slide and using tables of inflammation grading, a significant association between wood dust exposure and average grading of neutrophils (p=0.0001), lymphocytes (p=0.0067) and bacteria (p=0.0247) was shown (not modified by cigarette smoking). The rhinological symptoms were most frequently reported in exposed than controls and significantly correlated only with a decrease in goblet cell (p=0.043). Out of 73 exposed, 34 (46.6%) showed an exposure below 0.5 mg/m3, 31 (42.5%) between 0.5 and 1 mg/m3, 7 (9.33%) between 1 and 5 mg/m3, and 1 exceeded the italian occupational exposure limit of 5 mg/m3. Splitting the exposed subjects into two classes of exposure (cut-off 0.5 mg/m3), there was a significant association between wood dust exposure and the increase in neutrophils (p=0.08). Neutrophilia shows a significant correlation with exposure to hardwood (OR 3.99, p=0.047), while the presence of bacteria correlates with softwood exposure (OR 11.35, p=0.005).

Discussion
Nasal cytology by scraping is a simple, atraumatic and cheap technique in the differential diagnosis of inflammatory rhinitis. Our results, collected with this method, confirm that wood dust exposure determine an acute and/or chronic nasal mucosal inflammation.