'Eosinophilic fungal rhinosinusitis': a common disorder in Europe?

The traditional criteria for the diagnosis of allergic fungal sinusitis include chronic rhinosinusitis, "allergic mucin" (mucus containing clusters of eosinophils), and detection of fungi by means of histological examination or culture. In 1999, a group of Mayo Clinic researchers, with a novel method of mucus collection and fungal culturing technique, were able to find fungi in 96% of patients with chronic rhinosinusitis. Immunoglobulin E-mediated hypersensitivity to fungal allergens was not evident in the majority of their patients. Because the presence of eosinophils in the allergic mucin, not a type I hypersensitivity, is probably the common denominator in the pathophysiology of allergic fungal sinusitis, the Mayo Clinic group proposed a change in terminology from allergic fungal sinusitis to eosinophilic fungal rhinosinusitis. Using new techniques of culturing fungi from nasal secretion, as well as preservation and histological examination of mucus, we investigated the incidence of "eosinophilic fungal rhinosinusitis" in our patient population. STUDY DESIGN METHODS: In an open prospective study nasal mucus from patients with chronic rhinosinusitis as well as from healthy volunteers was cultured for fungi. In patients, who underwent functional endoscopic sinus surgery, nasal mucus was investigated histologically to detect fungi and eosinophils within the mucus.

Fungal cultures were positive in 84 of 92 patients with chronic rhinosinusitis (91.3%). In all, 290 positive cultures grew 33 different genera, with 3.2 species per patient, on average. Fungal cultures from a control group of healthy volunteers yielded positive results in 21 of 23 (91.3%). Histologically, fungal elements were found in 28 of 37 patients (75.5%) and eosinophilic mucin in 35 of 37 patients (94.6%). Neither fungi nor eosinophils were present in 2 of 37 patients (5.4%).

Our data show that the postulated criteria of allergic fungal sinusitis are present in the majority of patients with chronic rhinosinusitis. Either those criteria will be found to be invalid and need to be changed or, indeed, "eosinophilic fungal rhinosinusitis" exists in the majority of patients with chronic rhinosinusitis. Based on our results, fungi and eosinophilic mucin appear to be a standard component of nasal mucus in patients with chronic rhinosinusitis.