A Neuro-Ophthalmic Presentation of Allergic Fungal Sinusitis

Allergic fungal sinusitis (AFS) is estimated to represent ~10% of all chronic sinusitis. A type 1 hypersensitivity response to anaerobic fungal proliferation in eosinophilic mucin within the sino-nasal cavities is believed to be the underlying pathophysiology. Although AFS is not invasive, the inflammatory reaction produces bony erosions with orbital and intracranial involvement in ~56% of all cases. Ophthalmic manifestations are seen in 30% of AFS cases, including proptosis (most common), epiphora, diplopia, blepharoptosis, visual loss, and ophthalmoplegia. Aspergillosis is the most known etiology, but Dematiaceous fungi are the most frequent culprits in the USA.