Sebaceous Cyst Pictures: What They Look Like (Real Patient Photos)

What a Sebaceous Cyst Looks Like

“Sebaceous cyst” is the everyday term for two closely related lumps — epidermoid and pilar cysts — that form when skin cells and keratin become trapped in a sac under the surface. They share a recognisable look: a firm, round, mobile lump, smooth to the touch, ranging from a few millimetres to several centimetres. On the face and neck they are often small and noticeable; on the back they can grow larger before you notice them; on the scalp (pilar cysts) they feel like smooth, firm bumps and often run in families. The most useful identifying feature is the central punctum — a small dark pore in the centre of the lump. If you can see one, and the lump is mobile rather than fixed to deeper tissue, a cyst is likely. A thick, cheesy material with a distinctive smell may occasionally escape from the punctum; this is trapped keratin, not pus.

What an Infected Sebaceous Cyst Looks Like

An infected or inflamed cyst changes appearance quickly: the skin becomes red, the lump swells and grows tense, it feels warm and tender, and it may discharge pus rather than keratin. The example below shows a large, infected sebaceous cyst before treatment.

Why the Photographs of “Infected” Cysts Are Usually Mislabelled

Search for images of an infected cyst and you will find pictures of red, angry, tender lumps. Most of them are not infected.

When a cyst wall leaks or ruptures, keratin escapes into the surrounding tissue and the body reacts to it as a foreign body. That reaction produces exactly the appearance people photograph: red, hot, swollen, painful — and no bacteria involved. It is inflammation, not infection.

“Many patients are surprised to learn that a painful, red cyst is often inflamed due to rupture rather than bacterial infection, so antibiotics alone frequently don’t solve the problem.”

Bacteriological studies have found that inflamed and uninflamed cysts carry a broadly similar microbial picture, which is why a red cyst is not automatically treated as infected. In this clinic roughly one cyst patient in five arrives during or just after a flare of this kind.

The Discharge Is More Reliable Than the Redness

If something has come out, its appearance tells you more than the colour of the skin around it.

So the terrible smell on its own does not mean infected. White and cheesy is a cyst behaving normally.

What Cysts Look Like on the Back, Face, Scalp — and Under the Skin

Patients often search for pictures of cysts on a specific body part, and location genuinely changes what you see: On the back, cysts tend to grow larger before anyone notices them — it is the classic site for a cyst that has quietly reached several centimetres. In our experience back cysts also sit deeper, have thicker walls and are more likely to become inflamed or rupture, which is why the large infected example above is so typical of the area. On the face, cysts are usually smaller but noticed early, often as a firm pea-sized dome on the cheek, jawline or behind the ear, sometimes with a visible punctum. Facial cysts usually have an ultrasound before removal, and the incision is planned along natural skin lines. On the scalp, smooth firm bumps that feel almost bony are typically pilar cysts — they often run in families and can be multiple. “Under the skin” is how most people describe any cyst that has no visible opening: what you see is a smooth mound that moves slightly when pushed, with normal skin over the top. If the lump is fixed, hard or growing fast, that is not a typical cyst appearance — get it checked.

What the Site Changes About the Appearance

• Back. Reaches a much larger size before presentation, more likely to have inflamed or ruptured, often a thicker wall, and sits deeper.
• Scalp. Usually a pilar cyst — well encapsulated, firm, and it shells out cleanly at surgery, so recurrence is low when removed intact.
• Face. Smaller when presented, because it is visible. The trade-off is that the scar is visible too, which is why incision placement matters more here than anywhere else.

One other thing the photographs do not show well: the punctum is not always there. Patients expect every epidermoid cyst to have that visible central dot, but many do not have one — particularly after a previous episode of inflammation has altered the surface.

Is It a Cyst, or Something Else? How the Lumps Compare

Several common lumps are mistaken for sebaceous cysts. The differences below help you describe yours accurately — but only an in-person assessment can confirm a diagnosis, because some look alike to the eye.

If your lump is hot, tender and appeared within days, compare it against our dedicated guide to cyst vs abscess. A soft, squidgy lump with no punctum is more likely a lipoma than a cyst, while a fixed, hard or rapidly changing lump should always be assessed promptly to rule out anything more serious.

And a caution that the comparison photographs cannot convey: not every lump is a cyst. Lipomas, dermatofibromas, pilomatricomas and, occasionally, skin cancers all arrive referred as “cysts”. No photograph — yours or ours — settles that. It is why the lump is examined before anything is planned.

What Removal and Healing Actually Look Like

The reason cysts are removed surgically rather than simply drained is that the entire sac (the capsule) must come out in one piece — if any lining is left behind, the cyst regrows. Here is what complete removal looks like.

Removal at London Skin Clinic is a same-day “see and treat” procedure under local anaesthetic for the majority of cysts. The initial consultation is £100 and straightforward cyst removal is £400 (each additional cyst in the same visit £250). You can see the full process on our cyst removal page, and our guide to drainage vs surgical removal explains why excision gives a permanent result.

Cysts on the eyelid (chalazia) look and behave differently from skin cysts; if your lump is on the eyelid, see our guide to eyelid cyst removal instead.

What Squeezing Actually Does — One Case

A man of 28 had a cyst on his cheek for three months. He noticed some white discharge, so he squeezed it like a spot, hoping to be rid of it.

The cyst became infected. He needed a hospital visit and two weeks of antibiotics before anything else could happen. Once the infection had cleared he came in and the cyst was removed, capsule and all, under local anaesthetic.

Two things went wrong when he squeezed it: the pressure increased the inflammation, and the break he made in the skin let bacteria in. As the surgeon puts it:

“Squeezing cysts almost never cures the problem as the capsule remains.”

The sac is the cyst. Emptying it leaves the thing that refills it, and adds an infection risk and a worse eventual scar for nothing.

When to Get a Lump Checked

Most sebaceous cysts are harmless and can be removed at your convenience. Have a lump assessed sooner rather than later if it is growing quickly, becomes painful, red or starts discharging, feels hard or fixed to deeper tissue rather than mobile, or if you are simply unsure what it is. According to the British Association of Dermatologists, epidermoid and pilar cysts are benign, but any lump that changes in character should be checked to confirm the diagnosis.

“Is This a Cyst?” — What People Ask on Reddit, Answered by a Surgeon

Half of Reddit’s skin communities are photographs of lumps with the caption “what is this?”. Here is how we would answer the three commonest versions.

“Can anyone tell from my photo whether this is a cyst or something worse?”

Honestly: no, and be wary of anyone online who says otherwise. A photograph shows colour and shape but not the two things that matter most — how the lump feels (mobile or fixed, soft or hard) and how it has changed over time. A photo can suggest a cyst; only an examination can confirm one. That is not gatekeeping, it is how diagnosis works.

“White cheesy stuff came out and it smells terrible — is it infected?”

Not necessarily. White, cheese-like material with an unpleasant smell is keratin — the cyst’s normal contents — not pus. Infection looks different: yellow or green discharge, spreading redness, warmth and increasing pain. Keratin leaking means the cyst has a route to the surface, and it will usually refill.

“r/popping made it look easy. Why shouldn’t I just squeeze it?”

Because the satisfying part of those videos is the contents, and the part that matters — the sac — stays behind. It refills, often inflamed, sometimes infected, and each squeeze adds scar tissue that makes the eventual proper removal harder. We regularly repair the aftermath of home popping attempts; the neat option was always the planned excision.

Questions patients often ask

What causes a sebaceous cyst to form?

These cysts form when skin cells and keratin become trapped in a sac beneath the surface, often after minor trauma, a blocked or swollen hair follicle, or a previous skin condition such as acne. Pilar cysts on the scalp tend to run in families. The trapped material gradually accumulates, which is why the lump slowly grows over time.

Are sebaceous cysts painful?

Usually not. An uninflamed cyst is typically painless and only noticeable as a lump. It becomes tender or painful when it gets inflamed or infected — at which point the skin reddens, the lump swells and feels warm, and it may discharge. Pain is a signal to have it assessed rather than to squeeze it.

How can I tell from a photo if my cyst is infected?

An infected cyst looks red and swollen, with shiny or stretched overlying skin, and may have a yellow-white head or be leaking pus rather than keratin. It also feels warm and tender, which a photo cannot show. If you have spreading redness, a fever or rapidly increasing pain, treat it as urgent and seek same-day assessment.

Will a sebaceous cyst go away on its own?

Occasionally a small cyst settles or shrinks temporarily, but most do not disappear completely because the sac remains under the skin and continues to fill. Even if it flattens for a while, it commonly returns. Complete surgical removal of the capsule is the only reliable way to resolve it permanently.

What does a cyst look like under the skin?

From the outside, a smooth, rounded mound with normal skin over the top, ranging from a few millimetres to several centimetres. It moves slightly when pressed and may show a small dark central pore (punctum). Under the surface it is a closed sac with a keratin filling and a distinct wall — which is exactly what the capsule photograph above shows after removal.

What does the scar look like after removal?

Excision leaves a fine line scar the length of the cyst, which fades over the following months — as shown in the three-week healing photo above. A skilled surgeon plans the incision along natural skin lines to minimise its appearance, and aftercare such as sun protection helps the scar settle well.

How much does sebaceous cyst removal cost in London?

At London Skin Clinic the initial consultation is £100 and straightforward cyst removal is £400, with each additional cyst removed in the same visit at £250. Most cysts are treated the same day under local anaesthetic, so assessment and removal can often happen in a single appointment.