Allergic fungal sinusitis (AFS), also referred to as
allergic fungal rhinosinusitis (AFRS), is a noninvasive, eosinophilic form of recurrent chronic allergic hypertrophic
rhinosinusitis. AFS has distinct clinical, histopathological, and prognostic findings that differentiate it from other forms of
sinusitis. The core pathogenesis and optimum treatment strategies remain debated. Concerns surround the use of
immunotherapy for AFS because
allergen-specific
immunoglobulin G (
IgG) induced by
immunotherapy could theoretically incite a Gell and Coombs type III (complex mediated) reaction.
Type I hypersensitivity is established by high serum levels of
allergen-specific
IgE to various
fungal antigens and positive Bipolaris skin test results.
Type III hypersensitivity is established by an
IgG-mediated process defined by the presence of
allergen-specific
IgG that forms complexes with
fungal antigen inducing an immunologic inflammatory response. These reveal the multiple immunologic pathways through which AFS can impact host responses. Recent literature establishing benefits of fungal
immunotherapy and no evidence of type III-mediated reactions, severe local reactions, or delayed reactions, indicate that application of AFS desensitization is a reasonable therapeutic strategy for this difficult to manage entity. Our review should encourage further clinical acceptance of AFS desensitization because the existing literature on this subject shows benefits of fungal
immunotherapy and no evidence of type III-mediated reactions, severe local reactions, or delayed reactions.