A seroma is a common and usually temporary complication following surgery, defined as a localized collection of serous fluid under the skin near the surgical site. This fluid, composed of blood serum and lymphatic fluid, accumulates in the space created when tissue is removed or dissected during an operation. While the body typically reabsorbs this fluid over time, a seroma often causes visible swelling and can cause discomfort. Understanding the physical characteristics of a seroma is important for anyone recovering from surgery.
Identifying the Visual and Tactile Signs
A seroma typically appears as a lump or generalized swelling beneath the skin, often near the incision site, developing anywhere from a few days to several weeks after surgery. The skin overlying the collection usually remains intact without the severe redness or warmth that might suggest a serious infection. The appearance is frequently described as a balloon-like swelling or a distinct bulge.
The tactile sensation is a defining characteristic, as a seroma feels soft and spongy to the touch. When pressed, the fluid inside the collection often shifts, a quality known as being fluctuant. A gentle tap on one side of the area may even cause a wave-like motion beneath the skin, indicating a mobile fluid collection.
Seromas are generally not severely painful, but they can cause mild tenderness, a feeling of fullness, or pressure against the stitches, particularly if the fluid volume is large. If the seroma is actively draining, the fluid that seeps from the incision is typically clear, pale yellow, or straw-colored. Rarely, a seroma may become encapsulated or calcify over a longer period, causing it to feel firmer than when it first appeared.
Common Sites of Seroma Development
Seromas form because surgical dissection creates a “dead space” beneath the skin where tissue was removed or separated from its underlying structures. This disruption of small blood and lymphatic vessels leads to the leakage of serum and lymph fluid into this cavity. If the body cannot reabsorb this fluid faster than it is produced, a seroma develops.
The risk of seroma development is highest following procedures that involve extensive soft tissue manipulation, large-volume tissue removal, or lymph node dissection. Common anatomical areas include the chest wall after breast surgeries, such as a mastectomy or lumpectomy. Seromas are also a frequent complication of abdominoplasty (tummy tuck), hernia repair, and large-volume liposuction.
Procedures involving the removal of lymph nodes, such as those in the armpit, neck, or groin, are particularly prone to seroma formation because the lymphatic channels are directly disrupted. The size of the surgical area and the extent of tissue lost contribute to the volume and likelihood of a seroma forming. Seromas often become noticeable about seven to ten days after surgery, sometimes appearing shortly after surgical drains have been removed.
How Seromas Differ from Other Post-Surgical Swellings
Distinguishing a seroma from other post-surgical collections, such as a hematoma or an abscess, is important for proper management. A hematoma is a collection of blood, not clear fluid, and usually presents as a firmer, often bruised swelling that appears rapidly within the first 24 to 48 hours after surgery. While a seroma is soft and contains clear or yellowish fluid, a hematoma feels dense and may display significant discoloration of the overlying skin.
An abscess indicates a localized infection and presents with symptoms generally absent in a simple seroma. An infected collection typically displays increased warmth, intense redness, and a high degree of pain and tenderness at the site. Systemic signs like a fever or an increase in heart rate are strong indicators of an abscess, which contains purulent or pus-filled fluid, often with a thick consistency and foul odor.
Seromas rarely present with these severe inflammatory or systemic signs unless they have become secondarily infected. The fluid from an abscess is thick and cloudy, while the fluid from an uninfected seroma remains thin and straw-colored. Small seromas are often managed with observation, whereas a diagnosed abscess requires immediate medical intervention, usually involving drainage and antibiotics.
Treatment Options and Medical Guidance
Many small seromas are self-limiting, meaning the body gradually reabsorbs the fluid over several weeks or months without medical intervention. Conservative management is the primary approach for collections that are asymptomatic and not straining the incision line. Compression garments are often recommended to help reduce the space where fluid can accumulate and encourage reabsorption.
Aspiration and Drainage
If a seroma is large, causing significant discomfort, or placing tension on the surgical incision, a physician may recommend needle aspiration. This outpatient procedure uses a sterile needle and syringe to withdraw the fluid, offering immediate relief and reducing the risk of complications like wound separation. Depending on the volume of fluid and continued production, repeated aspirations over several weeks may be necessary.
Advanced Treatment
For seromas that persist despite multiple aspirations or become chronically symptomatic, more aggressive treatments may be considered. This can include surgical options like placing a temporary drain or sclerotherapy, which involves injecting an irritant solution into the cavity to promote internal healing and closure. Any patient who suspects they have a seroma, particularly if they notice increasing swelling, pain, or signs of infection, should contact their surgeon for professional assessment.