Allergic fungal sinusitis (AFS)

Author: V. Dimov, M.D., Allergist/Immunologist and Assistant Professor at University of Chicago

Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at LSU (Shreveport) Department of Allergy and Immunology

Allergic fungal sinusitis is a chronic hyperplastic sinusitis with eosinophilic inflammation. It is associated with fungal allergens. The pathologic features are similar to allergic bronchopulmonary aspergillosis (ABPA). 5%-10% of patients with chronic rhinosinusitis who require surgery have AFS.

Causative fungi include Bipolaris, Curvularia, Alternaria, Drechslera, Helminthosporium, Fusarium, and Aspergillus. The most common cause of AFS is Bipolaris.

Clinical features of AFS

The typical typical patient is a young adult with a history of allergic rhinitis/chronic sinusitis which is refractory to therapy. Nasal blockage becomes worse as nasal polyps enlarge. CT of sinuses shows extensive mucosal disease with complete sinus opacification. There may be blood eosinophilia and elevated serum IgE.

Diagnostic criteria for AFS:

1. chronic sinusitis of at least 6 months with CT or MRI findings
2. nasal polyps
3. typical allergic mucin found at sinus surgery, with absence of tissue invasion
4. fungus in allergic mucin - histopathology/culture

Allergic mucin is often described as "peanut butter".

Treatment of AFS

Treatment consists of of surgical debridement and oral steroids.

Oral corticosteroids are usually initiated before surgery and are for three to four weeks postoperatively.

Antifungal agents have not been shown to significantly modify clinical course.

AFS is a chronic condition that requires life-long therapy. AFS recurrence varies in the range of 10-90%.

Related reading

Atrophic Rhinosinusitis: Progress Toward Explanation of an Unsolved Medical Mystery. Medscape, 2011.

Published: 05/09/2010

Updated: 03/09/2011