What Causes Fungal Sinusitis?
There are four types of fungal sinusitis:
Saprophytic Fungus—This happens when fungus or mold grows on top of mucus or mucous crusts inside the nose. In this case, the fungus is not really infecting the nasal tissue; it’s just “living” off the mucus in the nose. This may not cause any additional symptoms that were not already present, and treatment is the simple removal of the crusts with nasal washes or other methods.
Fungus Ball—This is caused by fungus getting caught in one of the sinuses, forming clumps of material that often contain bacteria as well. This is most often in the maxillary, or cheek, sinus, and usually occurs in patients whose immune system is working fine. Often, there are no symptoms, other than slight discomfort, until the fungus ball grows large enough to block off the sinus. This form of fungal sinusitis requires simple surgery to open and wash out the sinus. Anti-fungal therapy is generally not prescribed.
Allergic Fungal Sinusitis (AFS)—This form of fungal sinusitis results from an allergic reaction to any one of several different common fungi, and usually occurs in patients whose immune system is working well. Patients may only notice allergic-like symptoms of nasal congestion, a runny nose, and sneezing. As AFS gets worse, it can cause the sinuses to fill with thick mucus. Eventually, the sinuses can get bigger and start changing the appearance of the eyes and face. Surgery is required to treat this form of sinusitis, and without continued medical therapy afterward, recurrence is common.
Invasive Fungal Sinusitis—This is a severe infection of the nasal and sinus lining that can lead to the destruction of nasal/sinus tissue. There are three different forms of invasive fungal sinusitis:
- Chronic Indolent/Granulomatous Sinusitis is a very rare disease that is usually not seen in the United States. Patients have a normally functioning immune system, but for some reason, the presence of the fungus results in a severe immune response that destroys the lining of the nose.
- Chronic Invasive Sinusitis is seen in patients who do not have a normally functioning immune system. Typically, this is seen in patients with diabetes. The fungus invades the tissue of the sinuses, but the disease progresses very slowly.
- Acute Fulminant Invasive Fungal Sinusitis is seen in patients who do not have a functioning immune system. Severe diabetics, transplant patients, and those with lymphoma or leukemia are at the highest risk. In this disease, the fungus invades and destroys blood vessels that line the nose, resulting in the death of that tissue. This is a life-threatening disease and often requires emergency surgery and anti-fungal medications.
