Why do I get sebaceous cysts?

Despite the common name, many of these lumps are epidermoid rather than true sebaceous cysts. A blocked or damaged skin opening can allow keratin to build up inside a sac. Some appear without an obvious trigger; others follow skin irritation, injury, or an inflamed follicle. A family tendency can also contribute to repeated cysts. The lump may be painless, but inflammation can make it red, tender, and swollen. For context on lumps with different causes, read [Skin Lumps](/symptoms/skin-lumps/).

There is no reliable home method for removing the cyst wall. Avoid squeezing it, because pressure can rupture the sac into surrounding tissue and worsen inflammation. Reduce rubbing over the area and keep any opening clean and covered. If cysts keep returning in the same place, ask whether complete [Cyst Removal](/treatments/surgical-dermatology/cyst-removal/) is appropriate. An inflamed cyst may sometimes be treated with [Steroid Injection Into The Skin](/treatments/injectables/intralesional-steroid-injection/) after examination.

Book an assessment for a new or changing lump, especially if it is growing, repeatedly inflamed, or interfering with movement or clothing. Seek prompt care for spreading redness, marked pain, warmth, pus, fever, or rapid swelling. Those features can indicate an abscess or another problem; [Abscess Drainage](/treatments/minor-procedures/abscess-drainage/) may be considered by a clinician.

What type of cyst or lump is this? Is there a likely trigger in my case? How can recurrence be reduced? Would removal be useful before another flare? What signs should prompt an earlier review?