Medically reviewed by Dr. A.M. van Coevorden, dermatologist
Sebaceous cystA harmless little ball under the skin.
A sebaceous cyst, in Dutch known as a talgkliercyste or atheroomcyste, is a benign little ball under the skin, filled with sebum. It develops when the outlet of a sebaceous gland or hair follicle gets blocked, and it grows slowly. Sebaceous cysts are common, especially on the scalp, neck and back, and are never malignant. Treatment is only needed if the cyst bothers you or becomes inflamed.
What is a sebaceous cyst?
You feel a round, smooth lump that is attached to the skin above it and moves along when you shift the skin. In the middle, a small dark dot is sometimes visible: the blocked outlet. The size varies from a few millimetres to several centimetres, and there can be more than one. Preferred sites are the scalp, the face, the neck, the back and the chest. A cyst usually causes nothing. Sometimes it bursts open and yellowish-white, greasy content comes out that can smell unpleasant, and sometimes it becomes inflamed: the lump then turns red, warm, swollen and painful.
How does a sebaceous cyst develop?
The skin contains thousands of small glands that produce sebum, the oil that keeps the skin supple. If the outlet of such a gland or of a hair follicle gets blocked, the sebum can no longer escape and accumulates in a little ball with a capsule around it. Why this happens to one person and not another is not precisely known; there is no way to prevent it. A sebaceous cyst has nothing to do with poor hygiene.
What can you do yourself?
A sebaceous cyst that causes no trouble can simply stay. Keep the area clean with lukewarm water and a mild cleanser, and protect it against rubbing from clothing or shaving. A cyst will not disappear through self-care: the capsule stays in place, even when content has come out.
Please note
Do not squeeze a sebaceous cyst and do not pierce it. The wall can tear, spreading the content under the skin and potentially causing a serious inflammation; moreover, the cyst then almost always returns.
When to see a dermatologist or doctor?
Have the lump assessed if it becomes inflamed: red, warm and painful. The doctor then first treats the inflammation, sometimes with a small incision to relieve the pressure; the cyst itself is removed later, in a quiet phase. The cyst can also be removed if it bothers you because of its size or location: a minor procedure under local anaesthesia, in which the cyst is removed capsule and all so it does not return. And if you are unsure whether it really is a sebaceous cyst, for instance because the lump feels hard, is fixed to the tissue beneath or grows quickly, always have it looked at.
Please note
A lump that grows quickly, feels hard or is fixed to the tissue beneath it does not fit a sebaceous cyst. Always have such a lump assessed.
Frequently asked questions
Is a sebaceous cyst dangerous?
No. A sebaceous cyst is benign and never becomes malignant. The only things that can happen are that it grows, bursts open or becomes inflamed, and even that is very treatable.
Can you squeeze a sebaceous cyst?
No. Squeezing or piercing can tear the wall, spreading the content under the skin and potentially causing a serious inflammation. Moreover, the capsule stays in place, so the cyst almost always returns.
Does a sebaceous cyst go away by itself?
Usually not. As long as the capsule sits in the skin, the cyst persists or returns, even after content has come out. Definitive removal is only possible with a minor procedure in which the capsule is removed in its entirety.
How is a sebaceous cyst removed?
With a minor procedure under local anaesthesia: through a small incision the cyst is removed capsule and all, after which the wound is stitched. If the cyst is inflamed, the inflammation is treated first and removal follows later.
When should you see a doctor about a lump under the skin?
If the lump becomes red, warm and painful, if it grows quickly, feels hard or is fixed to the tissue beneath it, or if you are unsure what it is. A dermatologist can assess from the picture whether it is a harmless sebaceous cyst; with an online consultation, include sharp photos.
Sources and more information
- Ik heb een talgklier-cyste (thuisarts.nl)
- Atheroomcyste (huidhuis.nl)