Optic Neuropathy Secondary to Allergic Fungal Sinusitis

Allergic fungal sinusitis (AFS) may mimic other disorders in Neuro-Ophthalmology. As opposed to invasive fungal disease often associated with an immunocompromised state, AFS generally presents in young immunocomptetent individuals with a history of atopy. It is most common in the Mississippi river valley but may present anywhere dematiaceous fungi are found. Allergic mucin, the pathologic hallmark, has been described as 'peanut butter' or 'axel grease' due to its tenacious viscosity.