Role of fungus in eosinophilic sinusitis

Abstract

Chronic rhinosinusitis is characterized by a broad diagnostic and etiologic spectrum. It has been postulated that fungal organisms might represent the immunologic target initiating and maintaining the disease process in patients with chronic rhinosinusitis as a common denominator. This review analyzes the available data to describe the current understanding of the role of fungus in the pathophysiology of chronic rhinosinusitis. Recent findings have demonstrated that using highly sensitive methods, the detection rate of fungi in nasal mucin can be increased to approximately 100% in patients and in healthy controls. If this ubiquitous fungal contamination were to be related to a causative mechanism in chronic rhinosinusitis, there would have to be an immunologic sensitization in patients in contrast with healthy individuals, which is yet not fully understood. However, studies were able to demonstrate cytokine production in blood-derived lymphocytes in the presence of fungi in patients, but not in healthy controls. Several questions arise. If this is a relevant finding, in what percentage of chronic rhinosinusitis patients could it be causative? Is chronic rhinosinusitis, then, a systemic disease? How is the extramucosal target in the mucin presented to the immune system? Is intranasal, topical antifungal treatment a successful option? The role of fungal organisms in the etiology of eosinophilic rhinosinusitis is reviewed with respect to novel findings, and arising questions are discussed in the light of recent investigations.