ABSTRACT
Fungal sinusitis spans a wide clinical spectrum that includes acute fulminant invasive infection in immunocompromised hosts, chronic infection in individuals who are not immunosuppressed, and allergic disease. Current classification schemes separate fungal sinusitis into four categories. The definitions of the four major forms of fungal sinusitis are as follows:
Acute invasive fungal sinusitis-rapid invasion of fungi through the mucosa of the nasal cavity or sinuses into soft tissues and blood vessels of the face, orbit, and cavernous sinus accompanied by hemorrhagic infarction and necrosis
Chronic invasive fungal sinusitis-subacute to chronic infection characterized by invasion through the mucosa of the sinuses leading to destruction of the bony structures of the sinuses and orbit and subsequent spread to the brain
Mycetoma-masses of fungal hyphae that grow in the sinus cavity but do not invade through the mucosa, also termed a fungus ball
Allergic fungal sinusitis-allergic response of the host to colonization of the sinuses by certain molds; this is not an infectious process
The fungi causing sinusitis are almost always molds; it is exceedingly uncommon to see fungal sinusitis caused by yeast-like organisms. The molds
that cause fungal sinusitis are ubiquitous in the environment; thus, exposure is quite common and disease is primarily determined by the status of the host. Local factors, such as nasal polyps and the presence of atopy in the host, are important in the development of allergic fungal sinusitis. Acute invasive infection occurs almost entirely in markedly immunosuppressed patients. The clinical manifestations of the four forms of fungal sinusitis differ, as might be expected, as does the approach to treatment. Not unexpectedly, overlap can occur with these four syndromes in some patients.
