Evidence of IgE-mediated hypersensitivity in allergic fungal sinusitis

Despite documentation of specific immunologic hypersensitivity in a few case reports, controversy continues as to the role of allergy versus true infection in the clinical entity of allergic fungal sinusitis (AFS). Using a modified radioallergosorbent test (RAST) to multiple fungal antigens, 16 patients meeting the histologic criteria of AFS and with positive fungal cultures were compared to 5 control patients with similar preoperative clinical findings but without histologic or culture evidence of AFS. All patients were immunocompetent and none demonstrated histologic evidence of tissue invasion. All AFS patients were RAST-positive to at least one fungal antigen in the family of their cultured organism with positive defined as class 2 or greater. No control patient was RAST-positive to either dematiaceous or Aspergillus fungal antigens. Thus, modified RAST testing can aid in the routine clinical diagnosis of AFS, and it provides further serologic evidence for a type I hypersensitivity in the pathogenesis of AFS.