Eosinophilic bacterial chronic rhinosinusitis

BACKGROUND: A subset of Chronic Rhinosinusitis (CRS) patients are those with eosinophilic CRS (ECRS). These patients remain the most refractory to medical and surgical intervention, and are thought to reflect an inflammatory process arising from a variety of causes. Recently the role of fungus in ECRS, defined as the presence of fungi in the eosinophilic mucin of CRS, has been proposed as causal in many cases. Other proposed causes of ECRS include bacterial superantigen induction of inflammation and aspirin sensitivity. DESIGN: Retrospective review. METHODS: Histopathology from patients with previously diagnosed ECRS was prospectively re-reviewed for bacterial and fungal presence and correlated with patients' demographic data. The study population was comprised of 55 specimens with ECRS from 34 patients, over a 3-year period from a single investigator at the University of Pittsburgh Medical Center. RESULTS: Histologic presence of bacteria was shown in 34 of 55 (62%) of all ECRS specimens. Specimens with fungal colonization were more often associated with bacterial presence than without bacteria (17 of 22 [77%] vs. 5 of 22 [23%], P < .02). CONCLUSION: Bacteria were present in almost two-thirds of all specimens, and most cases of fungal presence were accompanied by bacterial presence, potentially providing support for bacteria as a source of superantigen. Other possible reasons for the high rate of bacterial and fungal colonization of ECRS include increased pathogen exposure, or failure to eliminate pathogens.