The term “fungus ball" is a strange-sounding name, but the good news is that this condition is common, well-understood, and treatable.

What Exactly is a Fungus Ball?

A fungus ball is not a dangerous, invasive infection, nor is it cancer.

Think of your sinuses as small, air-filled rooms connected to your nasal passages. Normally, they produce a thin layer of mucus that traps dust, pollen, and other particles. This mucus is then swept out into the nose and swallowed.

A fungus ball, known medically as a mycetoma, is simply a dense clump of fungal debris that accumulates in one of these sinus cavities. Imagine a damp, poorly ventilated corner where dust bunnies might collect over time. A fungus ball is similar—it's a tangled mass of fungal elements, mucus, and debris that gets trapped inside a sinus.

The fungus doesn't invade your sinus lining or bone. It just sits there, growing slowly into a dense, clay-like or cheesy-textured ball.

Why Does This Happen? Am I Unclean?

Not at all. Fungal spores are everywhere in the air we breathe every day. For most people, our sinuses clear them out without any issue. A fungus ball forms when the normal ventilation and drainage system of a sinus is compromised.

The most common scenario is:

1. Blockage: The small opening (ostium) of a sinus gets blocked. This can be due to chronic inflammation, a deviated septum, a nasal polyp, or even previous dental work, especially on the upper teeth whose roots are close to the maxillary (cheek) sinus.

2. Stagnation: With the opening blocked, air and mucus can't get out. The sinus becomes a warm, dark, and moist environment—the perfect breeding ground for fungus.

3. Accumulation: Fungal spores that enter the sinus get trapped. Instead of being cleared away, they begin to grow and accumulate, forming a dense ball over many months or even years.

It has nothing to do with personal hygiene.

What are the Common Symptoms?

Fungus balls can grow for a long time without causing any symptoms. When they do, the symptoms are often non-specific and can be mistaken for chronic sinusitis. They almost always affect only one side of the face.

Common signs include:

• One-sided nasal congestion or stuffiness.

• A feeling of pressure, fullness, or heaviness in the cheek or forehead.

• Thick, discolored, and sometimes cheesy or chunky post-nasal drip.

• A foul odor or bad taste in the mouth (cacosmia).

• Chronic headache or facial pain.

In many cases, a fungus ball is discovered incidentally when a CT scan of the sinuses or head is done for another reason, like evaluating a headache or planning dental work.

How Do We Diagnose a Fungus Ball?

Diagnosing a fungus ball typically involves a two-step process:

1. Nasal Endoscopy

Your ENT doctor will use an endoscope—a thin, rigid tube with a light and camera on the end—to look inside your nasal passages. They might see signs of inflammation or discolored mucus draining from one of the sinus openings, which can be a clue. However, the fungus ball itself is hidden inside the sinus, so it's often not directly visible.

2. CT Scan

A Computed Tomography (CT) scan is the tool for diagnosis. On a CT scan, a fungus ball has a very characteristic appearance:

• It shows up as a complete clouding (opacification) of a single sinus cavity.

• The material inside often appears very dense, sometimes with bright white flecks. These are often described as metallic densities, which are thought to be calcium deposits within the fungal debris.

While a CT scan can give us a very strong suspicion, the final, definitive diagnosis is only made after the material is surgically removed and examined in a laboratory.