The role of fungus in diseases of the frontal sinus

Fungal disease of the nose and sinuses is classified based on clinical, radiologic and histologic findings. Most commonly accepted classification schema divides fungal rhinosinusitis into invasive and non-invasive diseases based on histopathologic evidence of fungus invading the host tissue. Acute fulminant invasive fungal sinusitis (AFIFS) is almost always seen in immunocompromised patients. Accordingly, treatment of AFIFS involves reversal of any underlying immunosuppression, if possible, concurrently with timely and aggressive medical and surgical therapy. Chronic invasive fungal sinusitis (CIFS) involves tissue invasion by fungi, though it has a slower clinical course compared to AFIFS. Treatment involves debridement of involved tissue coupled with antifungal therapy. Paranasal sinus fungal ball results from accumulation of dense fungal elements in a sinus cavity in the absence of mucosal invasion. Single sinus involvement is most common and the sinus CT will frequently demonstrate areas of hyperdensity. Endoscopic removal of the fungal ball is typically curative. Allergic fungal rhinosinusitis (AFRS) involves atopy against fungal antigens with resultant intense eosinophilic inflammation perpetuated through sinus ostial obstruction. Surgery represents an integral component to treatment of AFRS, combined with systemic and topical steroid therapy.