Low Incidence of Allergic Fungal Rhinosinusitis in Japanese Patients.

Background: Allergic fungal rhinosinusitis (AFRS) is a noninvasive fungal disease of the sinuses with a very high recurrence rate. A very small number of Japanese cases have been reported.

Material and methods: The subjects were 6 patients with AFRS out of 429 patients who underwent endoscopic sinus surgery at Kagawa Rosai Hospital between December 2011 and November 2017. We retrospectively examined the clinical features and outcomes of these 6 patients.

Results: The incidence of AFRS was 1.4% (6/429). Allergic fungal rhinosinusitis was unilateral in 5 cases and bilateral in 1. Computed tomography revealed hyperdense areas representing allergic mucin, but no patient exhibited bone erosion. Magnetic resonance imaging showed hypointense or no signal regions at the locations of allergic mucin. Postoperatively, 1 patient developed recurrence. Because the recurrent patient had no significant symptoms, he refused further surgery and received drug therapy. Preoperative eosinophil counts and total IgE levels were elevated in all patients; postoperatively, both remained high in the patient who developed recurrence. Postoperative treatments included steroid therapy and nasal irrigation.

Conclusions: Allergic fungal rhinosinusitis is less prevalent in Japan than in Western nations. Peripheral blood eosinophil and serum IgE values may be used as the biomarkers.

Significance: Allergic fungal rhinosinusitis is prone to recurrence. Postoperative treatment including steroid therapy is important in the management of AFRS.