Seroma · What Is It, Causes, Treatment, and More

Published: Nov 06, 2025

Author: Nikol Natalia Armata, MD•

Editor: Alyssa Haag, MD•

Editor: Józia McGowan, DO, FACOI, FNAOME, CS•

Editor: Arianna Succi, MD•

Editor: Ahaana Singh•

Editor: Kelsey LaFayette, DNP, ARNP, FNP-C

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What is a seroma?

A seroma, one of the most common post-surgical complications, refers to the accumulation of uninfected and clear (i.e., serous) fluid under the skin. Seromas are usually found near the site of a surgical incision and can form soon after surgery or, sometimes, even weeks later.

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What causes a seroma?

Usually, seromas develop in areas where tissue has been surgically removed. Dead space, or a remaining empty cavity in between tissues, may form as a result of improper healing of the surgical wound. Damage to neighboring lymphatic vessels during surgery can cause leakage of serous fluid into the dead space, resulting in seroma formation.

Abdominal wall reconstructions, hernia repairs, and removal of masses, such as thyroid tumors, require extensive separation of multiple layers of skin and tissue, potentially resulting in seroma formation. Similarly, fluid can accumulate after various kinds of plastic surgeries, such as abdominoplasties (i.e., tummy tucks), during which excess fat and skin are removed from the abdomen, and breast reconstruction surgeries. Seroma formation also commonly occurs in individuals who undergo breast removal surgery, whether partial breast tissue removal (i.e., lumpectomy) or total breast tissue removal (i.e., mastectomy). Liposuction, a procedure which removes large amounts of fat tissue, and body contouring, which redistributes fat tissue, both increase the risk of creating dead space and seroma formation. Finally, seromas can appear weeks after surgery when drainage tubes, used to prevent fluid accumulation under the skin, are removed earlier than recommended.

What does a seroma look like?

A seroma can be easily identified during physical examination, typically presenting as a soft, swollen lump that discharges clear fluid near the surgical incision site. When physical examination cannot confirm the diagnosis, a bedside ultrasound can provide better visualization of the seroma. If the seroma is large in size, the surrounding area may become inflamed and painful. If the seroma becomes infected, it may appear red and feel very tender and warm to the touch. Infected seromas often lead to the formation of an abscess (i.e., a collection of pus).

How are seromas treated?

Treatment for seromas largely depends on the severity of the fluid collection. Often, the body naturally reabsorbs a seroma, resolving the issue without the need for treatment. When small seromas do not fully reabsorb, they typically do not have any significant impact on an individual's health and may not require treatment. On the other hand, more severe cases may require further medical care. If the seroma increases in size or shows any sign of infection (e.g., redness, pus), a healthcare professional may drain it using a needle and a syringe, a procedure known as aspiration. Aspiration of clear fluid not only confirms the diagnosis but can also alleviate pain. This procedure may be repeated if the first aspiration does not completely drain the seroma. Additionally, compression bandages can be applied to the affected area in order to minimize lymphatic leakage and prevent reoccurrence. In rare instances, if the seroma persists despite non-surgical treatments, surgical intervention may be necessary.

Do seromas self-resolve?

Small seromas often reduce in size and go away on their own. However, if seromas grow larger or appear infected, they may need to be treated by a healthcare professional. Larger seromas usually require treatment by a healthcare professional.

What happens if a seroma is left untreated?

If a sizable seroma is left untreated for a long period of time, a thin cover of tissue called a fibrous capsule can develop around the mass. The capsule can make it more difficult for the seroma to drain, allowing fluid to accumulate rapidly. In such cases, frequent aspirations become necessary, and surgical removal is often suggested. Moreover, an encapsulated seroma poses an increased risk of infection and abscess formation. If there is any sign of infection -- such as high fever, redness, or pain in the affected area -- medical advice should be sought, as antibiotics and abscess drainage may be necessary for symptoms to improve.

What are the most important facts to know about seromas?

A seroma refers to the accumulation of clear fluid under the skin, typically near the site of a surgical incision. A seroma usually forms after reconstructive surgery, during which dead space is created. Seromas typically appear as a soft, swollen lump, varying in size and presence of inflammation. Small seromas often regress on their own; those that don’t can be aspirated using a needle and syringe. If a seroma persists, surgical removal may be considered. Large, untreated seromas pose an increased risk of infection and may develop a fibrous capsule, which can impair drainage.

Key Takeaways

Definition	Accumulation of serous fluid under the skin, typically appearing near a surgical incision site.
Causes	- Surgical removal of tissue and damage to lymphatic vessels → fluid accumulation within dead space. - Abdominal wall reconstructions (e.g., abdominoplasty) - Hernia repairs - Removal of masses (e.g., breast surgery)
Appearance	- Soft, swollen lump - Clear fluid discharge - If infected → red and tender, pus discharge, can form abscess
Treatment	- Small → usually spontaneous resolution - Larger, infected, or non-spontaneous resolution → aspiration - If persists → surgical removal - Increased risk of infection and fibrous capsule formation if a chronic seroma is left untreated

References

Goldman A, Wollina U, França K, Tchernev G, Lotti T. Chronic encapsulated seroma persisting for three years after abdominoplasty and a successful surgical solution. Open Access Maced J Med Sci. 2018;6(1):82-84. https://doi.org/10.3889/oamjms.2018.051

Janis J, Khansa L, Khansa I. Strategies for postoperative seroma prevention. Plast Reconstr Surg. 2016;138(1):240-252. https://doi.org/10.1097/prs.0000000000002245

National Cancer Institute at the National Institutes of Health. Seroma. In: NCI Dictionary of Cancer Terms. Accessed February 1, 2021. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/seroma

Salari N, Fatahi B, Bartina Y, et al. The global prevalence of seroma after abdominoplasty: A systematic review and meta-analysis. Aesthetic Plast Surg. 2021;45(6):2821-2836. https://doi.org/10.1007/s00266-021-02365-6

Turner EJ, Benson J, Winters Z. Techniques in the prevention and management of seromas after breast surgery. Future Oncol. 2014;10(6):1049-1063. https://doi.org/10.2217/fon.13.257