Seroma

A seroma is a pocket of fluid that builds up under your skin, most often after surgery. It forms in the empty space left behind as your body heals. You might notice a soft bump or swelling near the incision site. It can feel uncomfortable, tender or sore.

The fluid inside is called serous fluid. This is a clear, pale-yellow liquid made from blood plasma and lymphatic fluid. It seeps from tiny blood and lymph vessels into the open area created during surgery or an injury.

Most seromas go away on their own as your body absorbs the fluid over time. But if the area becomes very painful, bothersome or shows signs of infection, a healthcare provider can step in and treat it.

Seroma symptoms

Symptoms usually appear seven to 10 days after surgery or an injury. You might notice:

• A soft, squishy bump filled with fluid near the surgery site or injury
• Pain or soreness
• Trouble moving the area, depending on where it is
• A feeling of pulling or strain on your stitches or wound

In some cases, you might not have any symptoms at all.

Seroma causes

Seromas form when damage to tissue creates an open space inside your body. This space gives fluid a place to collect. The most common surgical causes are:

• Breast surgeries
• Hernia repair
• Plastic surgery
• Spinal fusion

During surgery, a provider may remove tissue and create flaps or small pockets. These open spaces make it easier for fluid to leak out and fill the gap.

Risk factors of a seroma

Any tissue damage can raise your risk for a seroma. Your risk goes up if you:

• Are above age 65
• Had a large or extensive surgery
• Had chemotherapy before surgery
• Had interrupted healing (like too much movement)
• Have overweight or obesity

Seroma complications

Most seromas aren’t dangerous. But some can lead to problems, especially if you’re healing from surgery or an injury. Watch for:

• Infection: A seroma can collect bacteria and turn into an abscess (a pocket of pus). Signs include skin discoloration, warmth, pain and fever. This usually needs drainage and antibiotics.
• Wound dehiscence: A large seroma can press on the incision and cause the wound to open. You may see wound edges pull apart.
• Flap necrosis: In surgeries that create tissue flaps, a big seroma may reduce blood flow to your skin. This can cause the flap to die, leading to an open wound that needs more treatment.
• Chronic seroma (pseudocyst): A long-lasting seroma can form a thick capsule around the fluid. It may feel firm and not go away on its own. In some cases, you may need surgery to remove it.

If you notice these or anything that concerns you, contact your healthcare provider.

Can a seroma burst?

A seroma usually doesn’t burst like a water balloon. But it can leak fluid if the incision site or your skin opens a little. You may see a thin, clear-yellow fluid coming from the area. Keep the site clean and covered with a fresh bandage until the drainage slows down.

Call your surgeon if the fluid looks like pus (thick, milky-white to yellow and stinky) or if you notice signs of infection.

How doctors diagnose a seroma

To diagnose a seroma, your healthcare provider will look at your skin and ask when symptoms started. They may gently press on the area to feel for fluid movement. They’ll also check for signs of infection.

Most people don’t need tests. But your provider may use an ultrasound to see the fluid pocket. They may also insert a small needle to remove a sample of the fluid (diagnostic aspiration).

Seroma treatment

Treatment depends on the size of the seroma and the symptoms you have. Common options include:

• Observation: Your provider may watch a small seroma that doesn’t cause pain. Many small ones go away as your body absorbs the fluid. You may need to limit your activities while it heals.
• Needle aspiration: Your provider may use a small needle to drain fluid from a larger or uncomfortable seroma. This may relieve pressure and help you feel better. Some refill, so you might need this done more than once.
• Temporary drain: If the seroma keeps coming back, your provider may place a small tube to drain the fluid for a few days.
• Sclerosing agent: In some cases, your provider may put medicine inside the pocket to help the walls stick together. This may stop the seroma from refilling.
• Surgery: Surgery is the last option. Your surgeon may remove the seroma sac if it forms a thick capsule or doesn’t go away with other treatments.

What is the recovery time for a seroma?

Recovery time varies. Small seromas may shrink in a little over a week, while larger ones may take up to six weeks to fully heal. If you have questions about when a seroma will go away, talk to your healthcare provider.

When should I see my healthcare provider?

Visit a healthcare provider if you notice a seroma and it’s:

• Causing discomfort
• Getting bigger
• Showing signs of infection (discoloration, severe pain and fever)
• Not improving after several weeks

What can I expect if I have a seroma?

A seroma can look serious, but it’s usually not an issue. The soft bump often goes away in a few weeks. If it doesn’t shrink or if it starts to bother you, let your provider know. Some seromas can turn into an infection or take longer to heal. Your provider can help you manage anything that comes up.