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
Common questions
What is a seroma?
A seroma is a pocket of clear, straw-colored healing fluid that collects under the skin where tissue was removed during surgery. NHS patient information describes it as a normal part of wound healing: when tissue or lymph nodes come out, the empty space fills with fluid, and sometimes it keeps collecting after the surgical drains come out. Seromas typically appear about a week after surgery or once drainage tubes are removed, and the area looks swollen and feels like liquid under the skin. Most are a nuisance rather than a problem: the body slowly reabsorbs the fluid over weeks to a few months. If a seroma grows large, tight, or painful, your team can drain it with a needle and syringe, sometimes more than once. A small seroma can be left alone safely. The signs that mean call your team: the swelling keeps increasing, the area becomes red, warm, or tender, you develop flu-like symptoms or a fever, or the swelling spreads beyond the surgery site, which can point to infection or lymphoedema instead.