Etiology of Allergic Fungal Sinusitis?
Over the past few decades, allergic fungal sinusitis (AFS) has become increasingly defined. Historically mistaken for a paranasal sinus tumor, allergic fungal sinusitis (AFS) now is believed to be an allergic reaction to aerosolized environmental fungi, usually of the dematiaceous species, in an immunocompetent host. This is in contrast to invasive fungal infections that affect immunocompromised hosts, such as patients with diabetes mellitus and patients with acquired immune deficiency syndrome (AIDS). Most patients with allergic fungal sinusitis (AFS) have a history of allergic rhinitis, and the exact timing of allergic fungal sinusitis (AFS) development can be difficult to discern. Thick fungal debris and mucin, as shown below, are developed in the sinus cavities and must be surgically removed so that the inciting allergen is no longer present.
@naresh Most rhinologists believe that allergic fungal sinusitis (AFS) is an allergic reaction to fungi, in which fungal debris, allergic mucin, and nasal polyposes are formed in the nasal cavity and paranasal sinuses. The causative fungi in allergic fungal sinusitis (AFS) are usually dematiaceous fungi, consisting of the genera Bipolaris, Curvularia, Exserohilum, Alternaria, Drechslera, Helminthosporium, and Fusarium, with a small component of allergic fungal sinusitis (AFS) caused by Aspergillus. In a 1996 review of English literature performed by Manning, 263 cases of allergic fungal sinusitis (AFS) were identified, of which 168 cases yielded positive fungal cultures. Of these 168 positive cultures, 87% were from the dematiaceous genera, while only 13% yielded Aspergillus.