You’re running your fingers through your hair and suddenly, there it is. A hard, smooth knot. Your mind immediately goes to the worst-case scenario, but honestly, it’s probably just a pilar cyst. If you’ve been scouring the internet for a picture of a pilar cyst to compare with that bump on your head, you’ve likely seen everything from tiny pebbles to literal golf balls emerging from someone’s scalp.
It’s gross. It’s fascinating. And it’s incredibly common.
Around 10% of the population gets these. That might not sound like a huge number, but when you consider how many people are walking around right now with a secret marble under their hair, it’s a lot. These aren’t like the pimples you get on your face. They’re deep. They’re sturdy. And they have a very specific look that sets them apart from more dangerous growths.
What a Picture of a Pilar Cyst Usually Reveals
When you look at a picture of a pilar cyst, the first thing you notice is the location. These things are obsessed with the scalp. About 90% of them show up there. While you might occasionally find one on the neck or arm, the scalp is their primary real estate because that’s where the densest concentration of hair follicles lives.
A pilar cyst—technically called a trichilemmal cyst—originates from the outer root sheath of the hair follicle. If you’re looking at a photo of one that hasn't been popped (please don't pop it), it looks like a smooth, dome-shaped protrusion. Unlike an epidermoid cyst, which usually has a visible "pore" or blackhead in the center (called a punctum), pilar cysts are usually closed off. They look like a little stone tucked under the skin.
The skin over the cyst is typically normal. It isn't usually red or angry unless it has become infected or "ruptured" internally. If you see a photo where the bump is bright red and leaking yellowish fluid, that’s a cyst in crisis. Normally, though, they just sit there, skin-colored and silent, for years.
The "Pop" Factor: What's Inside?
If you've ventured into the world of dermatological videos—think Dr. P Sandra Lee (Dr. Pimple Popper)—you’ve seen what happens when these are removed. Most people searching for a picture of a pilar cyst are actually looking for the "contents."
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It’s not liquid.
Inside that sac is a buildup of keratin. That’s the same protein that makes up your hair and nails. In a pilar cyst, the keratin is packed so tightly that it becomes a paste. It’s often white or yellowish. Because the cyst wall is quite thick and tough, a surgeon can often "shell" it out in one piece. In photos, these removed cysts look like small, white olives or even "pearls." It's oddly satisfying to see, which is why these images go viral so often.
Why Do These Things Even Happen?
It’s mostly genetics. If your mom or dad had these "head bumps," you’re likely to get them too. It’s an autosomal dominant trait in many families. This means you don't necessarily do anything "wrong" to get them. You didn't wash your hair poorly. You didn't use the wrong shampoo. Your hair follicles just have a genetic quirk that causes keratin to get trapped and encapsulated rather than shedding normally.
Dr. Arash Akhavan, a noted dermatologist in New York, often points out that these are benign. That’s the good news. They aren't cancerous. However, they don't go away on their own. They don't "dissolve." They just grow. Slowly. Very slowly. You might have one for twenty years before it gets big enough to actually bother you or show up in the mirror.
Spotting the Difference: Is it a Pilar Cyst or Something Else?
Not every bump on the head is a pilar cyst. This is where looking at a picture of a pilar cyst versus other growths becomes really important for your peace of mind.
- Lipomas: These are fatty tumors. They feel soft, almost doughy. If you push a lipoma, it might slide around under the skin. A pilar cyst feels much firmer, like a rubber ball or a knuckle.
- Epidermoid Cysts: These are the "cousins" of the pilar cyst. They can happen anywhere on the body. As mentioned, they usually have that little black dot in the middle. Pilar cysts almost never do.
- Seborrheic Keratosis: These look "stuck on" to the skin. They are waxy and often brown or black. They don't feel like a deep knot; they feel like a scab that won't come off.
- Pilar Tumor: This is the rare, scary version. In very few cases, a pilar cyst can turn into a "proliferating trichilemmal tumor." These look much more aggressive in photos—they might be ulcerated (meaning they have an open sore) and grow very quickly. If your "bump" suddenly starts growing like a weed or bleeding, stop looking at pictures and go to a doctor immediately.
The Reality of Living With Them
Most people live with pilar cysts for decades without a single issue. But then, things change. Maybe you hit your head on a cabinet door. Suddenly, that dormant little marble is inflamed.
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When a pilar cyst ruptures under the skin, it's painful. Your body treats that trapped keratin like a foreign invader. White blood cells swarm the area. In a picture of a pilar cyst that has ruptured, you’ll see intense swelling and redness. It can even mimic an abscess. At this point, a doctor can't just "pop" it out because the sac has disintegrated. They usually have to drain it and wait for the inflammation to die down before they can properly remove the remnants.
Another issue is hair loss. If a cyst gets big enough, the pressure it puts on the surrounding skin can actually kill off the hair follicles directly above it. You’ll see a little bald spot right on top of the bump. For many people, this is the "final straw" that leads them to the dermatologist’s office.
How Doctors Get Rid of Them (The "Cure")
You cannot squeeze these out like a zit. I mean, you can try, but you’ll probably just end up with a massive infection and a scar. Because the sac is thick, it requires a small incision.
The standard procedure is a "punch biopsy" or a simple excision.
- Numbing: The doctor injects lidocaine. This is the only part that really hurts—a quick sting and then nothing.
- The Cut: A tiny slit is made over the center of the bump.
- The Squeeze: This is what you see in the famous videos. The doctor applies pressure, and the "olive" pops out.
- The Sac: This is the most important part. If the doctor leaves even a tiny piece of the cyst wall (the sac) behind, the cyst will grow back. It’s like a weed; you have to get the root.
- Stitches: Usually, one or two stitches are enough. Because the scalp has such great blood flow, it heals incredibly fast.
Honestly, the whole thing takes about fifteen minutes. Most people are shocked at how easy it is compared to the years they spent worrying about the bump.
Does Insurance Cover It?
This is a tricky one. In the world of 2026 healthcare, insurance companies are stingy. If you tell them you want the cyst removed because it looks "ugly," they’ll label it cosmetic and hand you a bill for $500 to $1,000.
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However, if the cyst is painful, if it interferes with your ability to wear a hat or helmet, or if it’s constantly getting snagged on a comb and bleeding, it’s usually considered "medically necessary." When you talk to your dermatologist, focus on the physical discomfort or the fact that it’s growing.
What You Should Do Right Now
If you've looked at a picture of a pilar cyst and you're 99% sure that's what's on your head, don't panic. But don't ignore it either.
Check for these "Red Flags":
Is the skin over it red, hot, or painful?
Has it doubled in size in the last few weeks?
Is it oozing fluid or blood on its own?
Is it located somewhere other than your scalp (like your eyelid or groin)?
If the answer to those is "no," you’re likely fine to just monitor it. But if you're tired of feeling it every time you shower, make an appointment. A general practitioner can sometimes do the removal, but a dermatologist is your best bet for the cleanest result with the least amount of scarring.
Next Steps for Dealing With Your Cyst:
- The "Hands Off" Rule: Stop touching, poking, or trying to "pop" the bump. Irritating the cyst can cause it to rupture internally, making a simple 10-minute removal much more complicated.
- Documentation: Take a photo of the area today. Check it again in three months. Having a visual record of whether it's growing helps your doctor decide how to proceed.
- Hair Care: Be gentle when brushing. Use a wide-tooth comb to avoid snagging the skin over the cyst, which can lead to "micro-tears" and infection.
- Consultation: Book a "skin check" with a dermatologist. Ask them specifically to palpate the bump to confirm it's a pilar cyst and not a lipoma or something else.
- Review your family history: Ask your parents or siblings if they’ve had similar bumps removed. Knowing it’s a family trait can alleviate a lot of health anxiety.
Ultimately, a pilar cyst is just a "glitch" in your skin's plumbing. It’s a pocket of protein that forgot how to leave. While the photos might look intense, the reality is that these are manageable, benign, and very easy to fix once you decide you’re done living with your "head marble."