What is a seroma?
Last updated September 3, 2026.
A seroma is a pocket of clear, straw-colored healing fluid under the skin where tissue was removed. NHS leaflets describe it as a common, normal part of healing after operations that remove tissue or lymph nodes, such as breast surgery, lymph node clearance, or large lipoma removal. It usually shows up about a week after surgery or when drains come out, and the area feels swollen and squishy, like liquid under the skin. Most seromas are reabsorbed by the body over weeks to a few months. A large, tight, or painful one can be drained with a needle in clinic, occasionally needing repeat drainage over several weeks. You can live with a small seroma without harm.
What to do
- Leave small ones alone: most shrink away by themselves over a few months.
- Report growth: if the swelling keeps increasing or feels tight and painful, your team can drain it.
- Watch for infection: redness, warmth, tenderness, fever, or flu-like symptoms mean call your team.
- Do not squeeze or massage it yourself; that raises infection risk and slows reabsorption.
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