Cyst on Lower Back Under the Skin

A skin cyst is a sac beneath the surface that can contain keratin. Because the lower back meets chair backs, mattresses, waistbands, and sports equipment, friction or pressure may make it sore. You might notice a rounded lump, a central pore, or occasional thick discharge. The lower back can also develop other kinds of lumps, so a clinician should assess a new, firm, fixed, or changing area. See the overview of [Skin Lumps](/symptoms/skin-lumps/) for language to use when describing it.

Keep the skin clean and avoid squeezing, puncturing, or trying to empty the lump. Choose clothing that does not press on it and adjust sitting or sleeping positions if those increase discomfort. A clinician may recommend observation, [Steroid Injection Into The Skin](/treatments/injectables/intralesional-steroid-injection/), or [Cyst Removal](/treatments/surgical-dermatology/cyst-removal/) after examining the area. If the lump has opened, use a clean dressing and arrange medical advice rather than repeatedly expressing it.

Prompt assessment is needed if pain, warmth, swelling, redness, or drainage is increasing. Fever or redness spreading across the back may indicate infection. A painful collection may need [Abscess Drainage](/treatments/minor-procedures/abscess-drainage/) in a clinical setting. Seek urgent help if you feel seriously unwell, the swelling grows quickly, or severe back symptoms occur with it.

Is pressure contributing to the tenderness? Does the lump need imaging or simply monitoring? If it is inflamed, would an injection or drainage help? If removal is advised, how will the wound be protected from waistband and chair pressure?