Skin cyst
A skin cyst is a closed cavity beneath the skin filled with keratin, a soft substance with an unpleasant smell.
Prescription review online
A doctor will review your case and issue a prescription if medically appropriate.
Talk to a doctor online
Discuss your symptoms and possible next steps with a doctor online.
On this page
A skin cyst is a closed cavity beneath the skin filled with keratin, a soft substance with an unpleasant smell. It forms when a follicle or duct becomes blocked. It is benign, grows slowly and often needs nothing at all. What is worth knowing is when it does need removing, and why squeezing it at home is the worst possible idea.
How to recognise it
- a round lump under the skin, smooth and well defined;
- it moves together with the skin when you move it;
- from a few millimetres to several centimetres;
- soft or rubbery in consistency;
- often with a visible dark central point, which is the blocked pore;
- it does not hurt unless it becomes inflamed;
- if it opens, thick whitish material with a bad smell comes out;
- typical sites: scalp, face, neck, back, chest, behind the ears, scrotum.
Common types
- epidermoid cyst: the commonest, with a visible central punctum;
- trichilemmal or pilar cyst: on the scalp, with no central punctum, often multiple and running in families;
- lipoma: not a cyst but a benign fatty tumour; softer, lobulated and with no central point;
- milia: tiny white spots, particularly around the eyes;
- ganglion cyst: on the wrists and hands, of a different nature entirely.
When it becomes inflamed
This is the commonest complication. The cyst ruptures inwards and its contents irritate the surrounding tissue.
- it becomes red, hot, painful and grows rapidly over a few days;
- it may discharge;
- it is not always infected: in many cases this is a sterile inflammatory reaction, so antibiotics are not automatic;
- at this stage it is not excised: it is drained if necessary, and definitive removal is done weeks later once the tissue has settled.
When to see a doctor
- the cyst has grown quickly, hurts or is red;
- it is discharging or smells;
- there is fever or the redness is spreading;
- it is in an area of friction and bothers you daily;
- it bothers you cosmetically;
- it has appeared recently in an adult and is growing steadily;
- it is fixed to deeper tissue, hard or irregular: something else needs excluding;
- it bleeds or ulcerates;
- there are many cysts: there may be an inherited cause or an associated syndrome;
- it has become inflamed before: it is then worth removing it while quiet, so it does not recur.
Why you should not squeeze it
This is the most practical point in this article. When you squeeze a cyst:
- the capsule ruptures inwards and triggers intense inflammation;
- the capsule remains, so the cyst always refills;
- the risk of genuine infection rises;
- a scar is left where there would have been none;
- subsequent removal becomes harder, because the capsule is fragmented and stuck down.
Treatment
- observation: if it does not bother you, nothing needs doing;
- complete surgical excision including the capsule: the only definitive treatment, done under local anaesthetic and quickly;
- incision and drainage for an inflamed cyst: it gives immediate relief but is not definitive, because the capsule stays behind;
- steroid injection to settle inflammation before operating;
- antibiotics only if there is genuine infection with surrounding cellulitis;
- histological examination of what is removed where the picture is atypical.
After complete excision recurrence is uncommon. After simple drainage the cyst returns in most cases.
Common questions
Can it become cancerous? This is exceptional. But a lump that grows fast, is hard or is fixed should be assessed.
Will it go on its own? Rarely. It can stay unchanged for years.
Can it be removed with laser? Laser can open it, but unless the capsule is taken out it re-forms.
Why does it smell? From the degraded keratin inside; it does not mean it is infected.
Is it the same as a lipoma? No. A lipoma is fatty, softer and has no central punctum. Both are benign, but they are managed differently.
Will surgery leave a scar? Yes, a small linear one, usually far less noticeable than the cyst itself or the scar left by an inflamed one.
Online consultation
In an online consultation the doctor reviews photographs, distinguishes a cyst from a lipoma and other lesions, advises whether to remove it or leave it, recognises when it is inflamed and what to do at that moment, and explains why drainage does not solve the problem permanently.
This material is for information only and does not replace a medical consultation.
Consult with a doctor about Skin cyst
Discuss your symptoms and possible next steps with a doctor online.
Medically reviewed by
Reviewed on Jul 20, 2026
Online doctors for Skin cyst
Discuss your symptoms and possible next steps for Skin cyst with a doctor online.
