A prospective study of bacterial flora in nasal cavity of patients with persistent allergic rhinitis

It remains unanswered whether persistent allergic inflammation in nasal mucosa alters bacterial colonization and infection. The aim of this study was to investigate the bacterial flora in the nasal cavity of patients with persistent allergic rhinitis (PAR) and to correlate the bacteriological findings with presence of nasal symptoms, nasal eosinophil and neutrophil counts. A total of 255 subjects, aged between 6 - 74 years (mean 33.9 years) was randomly selected from a population-based rhinitis survey study in Singapore. All subjects went through a thorough medical history and nasal examinations. Serum specific IgE to a panel of common house dust mites, nasal cytological and microbiological examinations were performed. PAR was diagnosed in 107 patients and none of them had received previous regular therapy. There is a significant relationship between PAR and eosinophil grades, but not with neutrophil count. No statistically significant difference was found in quantitative and qualitative bacterial flora in nasal cavity between PAR patients and subjects with non-rhinitis or with non-allergic rhinitis. There is a significant inverse correlation between ongoing rhinorrhoea and quantitative bacterial load, and between signs of nasal mucosa (pale and edema) and the presence and type of bacterial pathogens. In conclusion, our study demonstrates that patients with untreated (or using PRN medicine) PAR do not result in a significant change in bacterial flora in their nasal cavity.