Allergic Fungal Sinusitis

Fungal sinusitis can present as one of four distinct clinicopathologic entities: 1) fulminant or acute; and three types of chronic, 2) indolent, 3) mycetoma, and 4) allergic fungal sinusitis (AFS). The first three forms differ both clinically and pathologically from AFS. The first reported cases of AFS were associated with the fungus Aspergillus, but recently other fungal organisms have been implicated. Five different fungal organisms have been found to cause AFS in 14 patients. The prevalence of AFS among patients with chronic sinusitis may be as high as 7%. The diagnosis is made on the histologic findings of inspissated allergic mucin containing 1) numerous eosinophils, 2) scattered noninvasive fungal hyphae, and 3) Charcot-Leyden crystals. In addition, AFS patients have a characteristic clinical and immunologic profile. The clinical presentation, diagnosis, and management of AFS are discussed. Uniformity of the classification of fungal sinusitis is proposed.