What should you know about a sebaceous cyst rupture under the skin?

When the cyst sac breaks, its thick contents can move into the surrounding skin. The original lump may flatten, while the area becomes swollen, firm, tender, red, or warm. You may notice an odour or drainage later. These changes can resemble an abscess, so an examination is useful.

Rupture does not necessarily remove the sac. The lump may return after the surrounding inflammation settles, particularly if the cyst lining remains.

Do not squeeze, massage, or pierce the area. Wash gently with clean water and mild cleanser, pat it dry, and use a clean dressing if it is leaking. Avoid shaving, scratching, or pressure over the site. Arrange an appointment to discuss whether inflammation treatment, drainage, or cyst removal is appropriate.

Record when the change started and whether the lump, redness, pain, or drainage is increasing. This information helps the clinician plan care.

Seek prompt medical attention if redness spreads, pain escalates, the skin becomes hot, drainage is thick or foul-smelling, or you develop fever, chills, or marked tiredness. Urgent care is needed for rapidly expanding swelling or symptoms involving the eye, mouth, or breathing.

Ask whether the cyst has ruptured, whether a collection needs drainage, how to dress the area, and whether removing the sac later could reduce recurrence.