A seroma is a collection of fluid that builds up under the surface of your skin. Seromas may develop after a surgical procedure, most often at the site of the surgical incision or where the tissue was removed.

The fluid, called serum, doesn’t always build up right away. The swelling and fluid may start collecting several weeks after surgery.

A seroma may form after a surgical procedure. In some cases, a seroma may form after a very minor surgery. Most seromas, though, will appear after a rather extensive procedure, or one in which a lot of tissue is removed or disrupted.

Your surgical team will place drainage tubes in and around the incision to try to prevent a seroma. The drainage tubes may remain in your body for a few hours or a few days after the surgery in order to prevent fluid buildup.

In many cases, the use of drainage tubes will be sufficient for preventing a seroma. However, that’s not always the case, and a week or two after the procedure you may begin noticing the signs of fluid buildup near the incision.

The most common types of surgery that result in seromas include:

Several factors increase your risk for developing a seroma after a surgical procedure. Not everyone with these risk factors will develop a seroma, however. These risk factors include:

  • extensive surgery
  • a procedure that disrupts large amounts of tissue
  • a history of seromas following surgical procedures

In many cases, a seroma will have the appearance of a swollen lump, like a large cyst. It may also be tender or sore when touched. A clear discharge from the surgical incision is common when a seroma is present. You may have an infection if the discharge becomes bloody, changes color, or develops an odor.

In rare cases, a seroma may calcify. This will leave a hard knot in the seroma site.

A seroma may drain externally onto your skin’s surface from time to time. The drainage should be clear or slightly bloody. If you begin experiencing the symptoms of an infection, the seroma may have developed into an abscess.

You’ll need medical treatment for an abscess. It’s unlikely to disappear on its own, and it may grow in size and become very uncomfortable. The infection may also make you very sick, especially if the infection spreads to the bloodstream. This puts you at risk of developing a severe illness or sepsis.

Symptoms of a serious infection include:

Serious or long-term problems related to a seroma are very rare. However, seek emergency medical attention f you experience any of the following symptoms:

  • white or very bloody drainage from the seroma
  • a fever that exceeds 100.4°F
  • increasing redness around the seroma
  • rapidly increasing swelling
  • increasing pain
  • warm skin on or around the seroma
  • rapid heart rate

You should also seek emergency medical attention if swelling causes the surgical incision to open up or if you notice pus draining from the incision site.

Minor, small seromas don’t always need medical treatment. That’s because the body may naturally reabsorb the fluid in a few weeks or months.

Medication won’t make the fluid disappear faster, but you may be able to take over-the-counter pain medications such as ibuprofen (Advil) to reduce any pain or discomfort, and to help ease any inflammation caused by the seroma. Talk with your doctor about your options.

Larger seromas may require treatment by your doctor. Your doctor may suggest draining the seroma if it’s large or painful. To do this, your doctor will insert a needle into the seroma and remove the fluid with a syringe.

Seromas may return and your doctor may need to drain a seroma multiple times. In some cases, your doctor may suggest removing the seroma entirely. This is accomplished with a very minor surgical procedure.

Surgical drainage systems are used in some surgeries to prevent a seroma from developing. Before your procedure, however, you should discuss with your doctor the likelihood of developing a seroma and what they can do to help prevent it.

Also, ask your doctor about compression garments. These medical devices are designed to help skin and tissue heal faster. They may also reduce swelling and bruising after a surgery. These dressings may help reduce your risk of developing a seroma.

These small steps may help prevent a seroma from forming if you have surgery. If a seroma does develop, be sure to check with your doctor so you both can decide on the best steps for treatment. Though bothersome, seromas are rarely serious, so rest assured that you’ll eventually heal.