Mr. Onur Gilleard
Qualifications & Experience
Mr Onur Gilleard is a distinguished consultant plastic surgeon on the GMC specialist register. He previously held an NHS consultant post at St Bartholomew’s Hospital in London, specialising in skin cancer and microsurgical reconstruction. In 2021, Mr Gilleard transitioned from the NHS to dedicate himself fully to private practice, allowing him to focus exclusively on providing personalised, high-quality care to his patients. He is recognised as an expert in laser treatments, having conducted research and developed advanced treatment protocols using cutting-edge laser technology to optimise both clinical outcomes and cosmetic results.
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The quickest way to tell them apart: a cyst grows slowly and is usually painless, smooth and mobile under the skin; an abscess appears quickly and is red, warm, very tender and full of pus. A cyst is a sac of trapped keratin or fluid; an abscess is a pocket of pus from a bacterial infection. An infected cyst sits in between — and can turn into an abscess — which is why a hot, painful lump should be assessed rather than guessed at.
This guide gives you a clear comparison, how to assess a lump at home, the warning signs that need a clinician, and how each is treated.
Cyst vs Abscess at a Glance
| Cyst | Abscess | |
|---|---|---|
| Cause | Blocked gland/follicle; trapped keratin or fluid | Bacterial infection; a pocket of pus |
| How fast it appears | Slowly, over weeks to months | Rapidly, over days |
| Pain | Usually painless (unless infected) | Painful, throbbing, very tender |
| Skin over it | Normal colour, smooth, dome-shaped | Red, swollen, warm |
| Feel | Firm, mobile, well-defined border | Fixed, fluctuant (fluid-feel), less defined |
| Contents | Keratin or fluid | Pus |
| Whole-body symptoms | None, unless infected | Fever/malaise possible |
What Each One Is
A cyst is a sac-like pocket under the skin. Sebaceous (epidermoid or pilar) cysts form when a gland or follicle blocks and fills with keratin. They grow slowly, are usually painless, and move freely when pushed — the skin over them looks normal.
An abscess is a collection of pus produced by the body fighting a bacterial infection. It develops quickly, is hot, red and painful, and feels fluctuant — as if there’s fluid moving under the surface. Because it’s an active infection, it can be accompanied by fever or feeling unwell.
The fourth state most guides leave out: inflamed but not infected
Cyst, infected cyst, abscess — that is the usual three-way split, and it is incomplete. There is a fourth state, and it is commoner than genuine infection.
When a cyst wall leaks or ruptures, keratin escapes into the surrounding tissue. The body treats that keratin as a foreign body and mounts an inflammatory response. The result is a lump that is red, hot, swollen and painful — with no bacteria involved at all.
“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.”
This matters practically, in two directions:
- It explains why antibiotics sometimes do nothing. If there is no bacterial infection, an antibiotic has nothing to act on. 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 with antibiotics.
- It explains why the lump does not disappear when the redness settles. The inflammation subsides; the sac is still there. That is a separate problem needing a separate solution.
In this clinic roughly one cyst patient in five arrives during or just after a flare-up of this kind.
Where an Infected Cyst Fits In
The grey area is the infected cyst, which has features of both. A previously quiet cyst becomes red, warm, tender and swollen, may grow quickly, and can develop a head and discharge pus — but it often keeps its original well-defined border and some mobility, which a primary abscess lacks. Two details from our own practice sharpen this picture: roughly 20% of the cyst patients we see arrive with an active or recent flare, and most red, swollen cysts turn out to be inflamed rather than truly infected — the redness is usually a foreign-body reaction to leaked keratin, not bacteria, which is why antibiotics alone often disappoint. If left, an infected cyst can progress into a true abscess as bacteria multiply. To see what this looks like, our photo guide to cysts shows real infected and non-infected examples, and our guide to Infected cyst: warning signs and treatment covers the symptoms in detail.
Checking a Lump at Home
Home assessment guides your decision about care — it doesn’t replace a diagnosis. With clean hands and good lighting:
- Look: normal-coloured skin suggests a cyst; red, inflamed skin suggests infection or an abscess.
- Feel gently: a cyst is usually mobile and firm; an abscess feels fixed, fluctuant and is very tender.
- Check temperature: the back of your hand near the lump — warmth points to infection.
- Recall the timeline: slow over months = cyst; fast over days = abscess.
What the Discharge Colour Tells You
If anything has come out of the lump, its appearance is one of the more reliable things you can assess yourself.
| What you see | What it means |
|---|---|
| White, cheesy, toothpaste-like | Normal cyst contents — keratin, the protein the cyst produces. On its own this does not mean infection, though it commonly smells unpleasant. |
| Yellow or green, thicker, foul-smelling | Active bacterial infection, and it needs assessing. A distinctly green tint comes from pyocyanin, a blue-green pigment produced by Pseudomonas aeruginosa — the same organism that gives the discharge its musty smell. |
So the unpleasant smell alone does not settle it. White and cheesy is the cyst doing what cysts do; yellow-green and foul is a different problem.
Warning Signs That Need a Doctor
Seek prompt or emergency care for any of the following:
- Rapidly spreading redness or red streaks extending from the lump (possible cellulitis or lymphangitis).
- Fever or chills (above 38°C) — a sign the infection may be systemic.
- Severe or worsening pain, or a throbbing, pulsating lump.
- High-risk sites: the facial “danger triangle” (nose to mouth corners), near the eyes, hands, neck, or genital area.
- Higher-risk people: diabetes, a weakened immune system, or poor circulation — seek help sooner.
For the full triage, see when an infected cyst is an emergency, and if a lump has burst, cyst rupture first aid.
“If your cyst is rapidly enlarging, hot, with redness spreading out into the surrounding skin, or you have a fever or feel generally unwell — or it’s on your face near the eye or nose — do not wait for an appointment: go to A&E the same day.”
The facial exception is not caution for its own sake. Infections around the eye and nose can track backwards into the eye socket and beyond, which is why they are treated as urgent rather than routine.
What Waiting Actually Costs — One Case
A patient in their forties had a small cyst on the back for over a year and left it alone. It flared — red, painful — and they waited another two weeks hoping it would settle.
By the time it was seen it was a tense abscess the size of a golf ball. It needed urgent incision and drainage under local anaesthetic, and because the cavity was large it had to be left open to heal from the inside over several weeks of dressing changes. Only once it had fully healed could the residual sac be removed — a bigger, more complex excision leaving a noticeably larger scar than it needed to be.
Had they come in when it first flared, this would almost certainly have been a short course of antibiotics and a small, planned excision with a neat scar. As the surgeon puts it: early is always smaller.
How Each Is Treated
An abscess is treated primarily by incision and drainage — a small cut to release the pus — often with antibiotics. Antibiotics alone usually aren’t enough, because the abscess wall limits how well they penetrate the pus pocket.
At London Skin Clinic, a painful, obviously collecting lump can be drained the same day, in clinic, under local anaesthetic — the area is numbed, a small incision releases the pus, and you walk out with the pressure gone.
At London Skin Clinic, a painful, obviously collecting lump can be drained the same day, in clinic, under local anaesthetic — the area is numbed, a small incision releases the pus, and you walk out with the pressure gone.
A cyst may need nothing if small and symptom-free, but the definitive treatment is complete surgical excision of the whole sac, which prevents recurrence. If a cyst is infected, the infection is settled first (sometimes with antibiotics or drainage) and the cyst removed once calm — for the reasoning, see drainage vs surgical removal. Either way, don’t squeeze or pop a lump at home — it spreads infection and worsens scarring.
At London Skin Clinic a consultant surgeon diagnoses the lump and treats it the same day where possible. The initial consultation is £100 and straightforward cyst removal is £400 (additional cysts £250 each). See the cyst removal page or book an assessment.
When Drainage Is Needed Rather Than Antibiotics
This is the decision that most often gets made wrongly, and the reasoning is worth understanding.
Antibiotics treat the cellulitis — the red, inflamed skin spreading around the lump. Once pus has actually collected into an abscess, antibiotics will not cure it, because they diffuse poorly into a walled-off pus collection. The pus has to come out. Drainage is not the fallback when antibiotics fail; for a collected abscess it is the definitive step.
The findings that indicate drainage:
- A soft, “squishy” fluctuant centre — the sign that pus has collected
- A defined abscess rather than diffuse redness
- A rapidly enlarging or tense swelling
- Severe throbbing pain
- A lump that has failed to settle after 48 to 72 hours of antibiotics
Drainage relieves the pain almost immediately, and where a cyst is obviously collecting it can be done the same day in clinic under local anaesthetic: the area is numbed, a small incision is made over the most fluctuant point, the pus is released and the cavity cleaned.
But drainage does not remove the sac. The cyst wall stays behind, which is why a drained cyst can refill and why a definitive excision is planned separately, once everything has calmed down. A retrospective series of 2,159 surgically removed epidermoid cysts reported a low complication rate of 2.2%, and made the same point about technique: to avoid recurrence the cyst wall has to be removed completely.
Source: Wollina U, Langner D, Tchernev G, França K. Epidermoid cysts — a wide spectrum of clinical presentation and successful treatment by surgery: a retrospective 10-year analysis and literature review. Open Access Maced J Med Sci. 2020;6(1):28–30. PMID 29483974.
Timing is not a detail either. Surgery is easier, the scar is better and recurrence is less likely when the inflammation has completely settled — typically around ten days after a flare, once the area is quiet.
“I had an epidermoid cyst removed at this clinic. I was very pleased with the experience, from the swift email communication up to the suture removal. The quote was very transparent and no hidden costs emerged at the end.”
Cyst or Abscess? The Threads Reddit Cannot Settle
“A&E lanced it and called it an abscess — but there’s still a lump weeks later. Why?”
Because underneath many “abscesses” is a cyst that got infected. Emergency drainage removes the pus, not the sac; once the infection settles, the original cyst remains and will usually refill. If a lump persists after drainage, that is the cyst announcing itself — and planned excision of the sac is what ends the cycle.
“My GP says cyst, but it looks exactly like the abscess photos online. Who’s right?”
Possibly both. An infected cyst genuinely mimics an abscess — hot, red, tender, sometimes pointing. The tell is history: if a slow-growing, painless lump was there for months before it flared, it is almost certainly a cyst that has become inflamed or infected, and the long-term plan differs from a simple abscess.
“I keep getting an ‘abscess’ in the exact same spot. Coincidence?”
Rarely. A recurrent collection at the same site is the classic signature of an underlying cyst (or, in specific areas like the groin and armpits, hidradenitis). Repeated drainage treats each episode; removing the underlying sac treats the cause.
Common questions
- How can I tell if I have a cyst or an abscess?
- A cyst is usually slow-growing, painless, smooth and mobile, with normal skin over it. An abscess appears quickly and is red, warm, very tender and fixed, often with throbbing pain and sometimes fever. If a lump is hot and painful, treat it as possible infection and have it assessed rather than self-diagnosing.
- Can a cyst turn into an abscess?
- Yes. If bacteria enter a cyst — often after trauma or squeezing — it can become infected and, if untreated, progress into an abscess as pus accumulates. Signs include increasing redness, pain, warmth and swelling. Early assessment can stop this progression and prevent complications.
- Is an abscess a cyst?
- No. A cyst is a slow-growing, usually sterile sac with a lining that produces its own contents; an abscess is an acute pocket of pus created by infection, without a permanent lining. They can overlap — an infected cyst can develop an abscess within it — but a primary abscess is an infection, not a cyst, and it does not leave a sac behind once treated.
- Is it safe to pop a cyst or abscess at home?
- No. Popping either can drive infection deeper, spread bacteria, cause scarring, and leave material behind that leads to recurrence. Both should be treated professionally in sterile conditions — and a cyst still needs its wall removed afterwards to stop it returning.
- Can antibiotics cure an abscess without drainage?
- Usually not. The wall around an abscess and the dense pus inside limit how well antibiotics penetrate, so drainage is the main treatment, with antibiotics used alongside for surrounding infection or in higher-risk cases. Relying on antibiotics alone often allows the abscess to persist or recur.
- Will a sebaceous cyst go away on its own?
- Most won’t. The cyst wall keeps producing keratin, so the lump persists or grows. A cyst may occasionally rupture and drain, but if the wall remains it usually refills. Lasting resolution needs removal of both the contents and the wall.
- What’s the difference between a sebaceous cyst and an epidermoid cyst?
- True sebaceous cysts arise from sebaceous (oil) glands and contain sebum, while epidermoid cysts come from skin cells and contain keratin. Most lumps people call “sebaceous cysts” are actually epidermoid cysts. They look similar — firm, dome-shaped lumps — and are treated the same way.
Part of our cyst removal guide: complete sebaceous cyst removal guide · infected cyst: when to seek help
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