Hematoma After Surgery: Safety, Recovery & Revision Guide
Swelling and bruising after an operation are ordinary, and most of what patients worry about in the first week is the expected course. A hematoma is different: it is blood collecting where it should not, and the findings that decide the question are not the size of the bruise. They are tension, growth over hours, worsening pain and a change in the skin over the swelling. Blood removed early leaves little trace. Blood left under pressure can change the contour for good. This site is about telling the two apart.
Chongqing West District Hospital, a tertiary general hospital in Jiulongpo District, Chongqing. This site is patient education; it cannot assess you. For a swelling that is tense or growing, contact your treating team rather than reading further.
A swelling that is tense, tight and larger on one side, and growing over hours rather than days; pain that is getting worse instead of settling; or skin over the swelling turning dusky, shiny, blistered or cold — any of these means seek emergency care now rather than waiting for a review appointment. Do not press on the area, do not apply heat, and do not take a medication that affects clotting. Blood left under pressure can damage the skin over it, and a collection that needs evacuating is not left to be looked at at the next appointment.
What ordinary swelling does, and what a collection does
Swelling after an operation is firm, even, and greatest in the first two or three days, and it then reduces. Bruising appears over days rather than at once, spreads a little, changes colour as it fades, and is usually similar on the two sides. Soreness improves steadily even when it is still present. A wound that is dry, with the edges held together, is what healing looks like. A firm ridge under the scar that softens over several weeks is ordinary. Mild asymmetry between the two sides is common after surgery and is not by itself a finding.
A collection behaves differently in three specific ways. It is tense rather than firm — the swelling feels tight and under pressure, and the skin over it may look shiny. It grows over hours rather than days, so a comparison an hour apart shows a change, where ordinary swelling is at its worst early and then settles. And it produces pain that is getting worse instead of better, which is the opposite of what ordinary recovery does after the first two days. A change in the skin over the swelling — dusky, blistered, cold or shiny — is the finding that means the tissue over it is being compromised.
The distinction matters because of what follows from it. Blood that is removed early leaves little trace and the contour recovers. Blood that sits under pressure, or that is left long enough to organise, can change the contour of the area permanently and can compromise the skin over it. That is why the assessment is made on tension, growth and the skin rather than on the size of the bruise, and why a collection that is tense is not watched until the next appointment.
What to do while you are worried
The first step is a telephone call rather than a search. Contact your treating team and say where the swelling is, when you first noticed it, and whether it is larger than it was an hour ago. If the team cannot be reached, call the hospital main line. If the swelling is tense and growing, if the pain is worsening, or if the skin over it has changed colour or become blistered, go to the nearest emergency department immediately rather than waiting for a reply.
- Do not press on the area. Pressing does not stop a collection, it can increase the bleeding, and it hides the finding from the clinician who examines you next. Note what it feels like and leave it alone.
- Do not apply heat or ice. Heat increases bleeding and ice obscures the appearance of the skin over the swelling, which is one of the findings that decides what happens next.
- Photograph it, and mark the edge. A photograph taken now in good light, and a soft mark on the skin at the edge of the swelling, allow a comparison an hour later. That comparison is more useful than any description.
- Keep the wound dry and leave the dressing alone. Do not remove dressings to look underneath, because the dressing is part of how the wound is being managed. Tell the team what you can see at the edges rather than unwrapping it.
If your concern is not acute — a bruise that is fading, swelling that is reducing, a firm ridge under the scar — that is a reasonable thing to raise at a review or in a telephone call, and it does not need emergency care. The list above exists to make the finding that cannot wait unmistakable.
How a suspected hematoma is assessed
The assessment is quick and it is made mostly at the bedside. These are its parts and what each one contributes.
What you describe, and how it changed
When you first noticed the swelling, whether it is larger than it was, whether the pain is increasing, and what operation you had and when. A photograph or a mark on the skin with a recorded time is the most useful thing you can bring, because it converts a description into a comparison.
Examination of the tension and the skin
The clinician feels whether the swelling is tense or soft, whether it is warm, whether it is confined to one side, and whether it is pulsatile. Then the skin over it: its colour, its temperature, whether it is shiny or blistered, and whether it is intact. Tension and the state of the skin over the swelling are the two findings that decide what happens next.
Blood tests
A blood count shows how much blood has been lost into the collection, which matters where the swelling is large or where there has been ongoing bleeding. Clotting tests are added where there is a reason to suspect a problem with clotting, or where the patient takes medication that affects it.
Imaging when a collection cannot be felt
Some collections sit deep to the muscle or in a plane that cannot be assessed by hand. Ultrasound is used where the examination is unclear, where the swelling is deep, or where it is important to distinguish a collection of blood from fluid, from an infection, or from ordinary swelling. It also shows the size and the plane of the collection.
Establishing what provoked it
A collection is more likely after a rise in blood pressure, after a period of strenuous activity or lifting too early, after straining, and in a patient who takes medication that affects clotting. Establishing which of those applies changes the plan, because a collection that recurs is usually one where the provoking factor was not addressed.
What is recorded
Where the collection was, how tense it was, what the skin over it looked like, what was done and when. This matters beyond the immediate episode, because a collection is a fact that changes how a later operation in the same area is planned and how the tissue is expected to behave.
What is dealt with immediately, and what waits
A collection divides into two groups by urgency, and the dividing line is tension and the state of the skin over it. The first group is dealt with immediately: a swelling that is tense and growing, pain that is worsening, a collection large enough to threaten the skin over it, or skin that has changed colour, become blistered or become cold. These are not observed, because the tissue over a collection under pressure can be permanently damaged while it is being watched, and because blood left in place can organise and alter the contour for good.
The second group waits, and it is the larger group. A soft collection that is not growing and is found at a review is assessed and then observed or aspirated as a planned procedure. Bruising that is fading, swelling that is reducing and a firm ridge under the scar are ordinary recovery and are raised at a review rather than treated urgently. The distinction is not the size of the bruise, which is the least useful measurement available, but whether the swelling is under pressure and whether the skin over it is healthy.
There is a third timing question, and it concerns the wound rather than the collection. Where a collection has been evacuated and the wound has been closed again, the tissue in that area has been through an extra procedure, and how it heals changes what can be planned later in the same area. That is one reason a surgeon will want to see how the area settles before planning anything further, and it is worth asking about at the end of treatment rather than at the beginning of a later one.
How to reach care, and what this site cannot do
This site publishes no emergency telephone number, no room number and no opening hours of its own, because a number printed on a website can be wrong at the moment it matters most. In an emergency, do not use this website to ask for help.
- Your treating team first. They know what operation you had, where the wound is and what the tissue was like, which is the information the judgement depends on. Call them before you search for anything else.
- The hospital main line next. If your team cannot be reached, the hospital can route you to the service that can help, and the contact page explains the channels.
- The nearest emergency department for a red flag. A tense and growing swelling, worsening pain, or skin over a swelling that has turned dusky, blistered or cold are not conditions to discuss online or to wait out at home.
Two things override anything written here. The first is your treating team's own written aftercare instructions: if they differ from this page, follow them. The second is your own judgement that something is wrong. With a collection, being seen early and told that nothing needs draining is a good outcome, and it costs far less than being seen after the skin over it has suffered.
After surgery: ordinary swelling, or a hematoma?
The left column is what ordinary swelling and bruising after surgery do. The right column is what needs care, and what to do about it. The findings that matter here are tension, growth and the skin, not the size of the bruise.
The safety guides
Each guide answers one question a patient actually asks after an operation. Read the two or three that match your situation rather than all of them.
Swelling and Bruising After Surgery: The Ordinary Course
Firm, even swelling that peaks in the first days, and bruising that travels and fades. What normal looks like, so that the abnormal is recognisable.
Read the guide →When Swelling Is a Collection: Telling the Difference
A hematoma is blood collecting where it should not. The findings that separate a collection from ordinary post-operative swelling, at the bedside.
Read the guide →The Red Flags of a Hematoma: Tense, Growing and Painful
Tension, growth over hours, worsening pain and a skin change: the four findings that mean a collection needs evacuating rather than watching.
Read the guide →What to Do in the First Hours After Noticing a Collection
Who to contact, what to describe, what to stop doing, and why pressing on the area is the wrong instinct when a swelling is tense.
Read the guide →How a Hematoma Is Assessed
Examination of the tension and the skin, blood counts, and imaging when a collection cannot be felt. What each finding changes about the plan.
Read the guide →Draining a Hematoma: The Procedure and the Timing
Aspiration at the bedside or evacuation in theatre, and why a collection under tension is not left for a review appointment.
Read the guide →Tension, not the size of the bruise, is what matters
If a swelling after surgery is tense or growing, contact your treating team and say what it feels like and whether it has changed. For a tense, growing swelling or a change in the skin over it, seek emergency care now rather than waiting for a review.
Frequently asked questions
How do I tell a hematoma from normal swelling?
By tension and by change over time rather than by size. Ordinary swelling is firm and even, is worst in the first two or three days, and then reduces. A collection is tense, feels under pressure, is often larger on one side, and grows over hours rather than days. Pain that is getting worse rather than settling is the third finding, and a change in the skin over the swelling is the fourth.
Is a big bruise a sign of a hematoma?
Not by itself. Bruising appears over days, spreads a little and fades, and its size depends on how much the tissue was disturbed rather than on whether a collection has formed. The size of a bruise is the least useful measurement available. What matters is whether the swelling under it is tense and growing, and whether the skin over it is healthy.
What happens if a hematoma is left alone?
Sometimes nothing, where it is small and not under tension. Where it is under pressure, blood left in place can compromise the skin over it and can organise into a firm mass that changes the contour of the area permanently. Blood removed early leaves little trace, which is why a tense collection is evacuated rather than observed.
Does draining it mean another operation?
Not always. A collection that is accessible and not under great tension can be aspirated with a needle at the bedside. Where the collection is large, deep, organised or continuing to bleed, the wound is reopened and the collection evacuated under a proper anaesthetic, which is a return to theatre rather than a new operation.
Why did this happen to me?
There is not always an answer, and that is worth saying plainly. A collection is more likely after a rise in blood pressure, after straining or lifting too early, and in a patient who takes medication that affects clotting. Sometimes none of those applies and the collection is a consequence of the operation itself rather than of anything the patient did or failed to do.
Will the result be affected?
It can be, and how much depends on how quickly the blood was removed and how the skin over it survived. Blood evacuated early usually leaves the contour intact. A collection that sat under pressure, or that damaged the skin over it, can leave a change in the contour or in the scar. That is why the decision is made on tension rather than on waiting.
Part of When Something Goes Wrong — 10 sites on this topic