A fungal ball is a mass that develops in your sinuses after you’ve breathed in fungal spores. Medications cannot treat it, but a doctor can surgically remove it.

Sinus fungal balls are a type of sinusitis, an infection of the sinuses. They occur when a fungus grows into a densely packed ball inside one of your sinuses, most commonly the maxillary sinus.

You can have a fungal ball with no symptoms. If you do have symptoms, they might resemble other forms of chronic rhinosinusitis.

Imaging tests can suggest the presence of a fungal mass. A doctor can use a procedure called an endoscopy to confirm a diagnosis and remove the fungal mass. A fungal ball will not go away on its own.

You can get a fungal ball by breathing in fungal spores. Researchers don’t know exactly how the fungus forms a fungal ball.

The most common fungus that forms a fungal ball is Aspergillus. It usually occurs in one of the maxillary sinuses (aka cheek sinuses), which are under your eyes and on either side of your nose. It can also occur in the sphenoid sinus near the center of your skull.

Fungal balls almost always occur on one side, but in some cases, they have affected sinuses on both sides.

Sinus fungal balls are more common among middle-aged and older adults. According to a 2020 retrospective study, the average age of diagnosis is about 54 years.

The study also found that sinus fungal balls were twice as common in females than in males.

Other risk factors include having previous nasal surgery or dental work.

A fungal ball doesn’t usually protrude down into the lower nasal passages where you can see it. A healthcare professional can usually see it only by looking inside your sinuses.

A doctor can see evidence of a fungal ball using medical imaging like a CT scan. They can confirm and observe the fungal ball using an instrument like an endoscope, which is a tube that goes inside the sinus.

The fungal ball might be dark brownish in color and round with an uneven surface. It might resemble thick mucus and appear cheesy and clay-like in texture.

Fungal balls are often asymptomatic, meaning they have no symptoms. It’s common for doctors to find them when performing examinations for other conditions or purposes. For example, a fungal ball might show up on a CT scan when you have the imaging test done for another reason.

If you do experience symptoms, they may include:

If you have symptoms of a fungal ball or chronic rhinosinusitis, a doctor might request a CT scan. This scan can show whether one of your sinuses contains a mass.

A doctor can use an endoscope to reach the fungus ball. They can locate the ball and remove it in the same procedure.

To get a definitive diagnosis of a sinus fungal ball, a doctor has to perform histology, which involves looking at the tissue of the ball under a microscope. This can confirm whether the ball is made of fungus, and if so, what kind.

Endoscopic surgery is the treatment for a fungal ball. A doctor removes the fungal mass and washes out the sinus. They might also take a sample of surrounding tissue and mucus to confirm the fungus has not spread.

After sinus fungal ball surgery, a doctor might recommend a topical rinse with an antifungal medication.

Here are answers to some of the most commonly asked questions about sinus fungal balls.

How common are fungal balls in sinuses?

Fungal balls are relatively uncommon but might be becoming more common. Older research published in 2013 found a prevalence rate of 0.9% in people who underwent sinus surgery between 1999 and 2004 and 4.1% between 2005 and 2010. The study looked at 4,485 people with chronic rhinosinusitis in South Korea.

A 2020 Korean study found a similar increase in cases from 2008–2017.

However, the prevalence of fungal balls varies by region.

Do fungal balls go away on their own?

Fungal balls do not go away without treatment. A doctor usually has to remove a fungal ball by endoscopic surgery. Left untreated, a fungal ball might damage your sinus wall or cause a blockage that results in a bacterial infection.

How do I know if my sinus infection is bacterial or fungal?

If antibiotics do not clear up your sinus infection, a doctor might suspect a cause other than bacteria, such as a fungus or virus. To determine whether the infection is fungal, bacterial, or viral, a doctor will test mucus or tissue from your sinus or nasal passages.

Fungal balls most commonly occur in one of the maxillary sinuses on either side of the nose below the eyes. They might not cause symptoms and are often discovered on a CT scan conducted for another purpose. Treatment for fungal sinus balls is removal with endoscopic surgery.