Why a soft, growing lump after a crash needs a closer look
The view from an orthopedic trauma surgeon and a wound specialist
A hard slide or crush can pull the skin and the fat beneath it away from the deeper tissue. The skin itself may stay unbroken. Blood and fluid can then pool in the gap. Doctors call this a Morel Lavallée lesion. Another name is a closed degloving injury. It often shows up near the hip, thigh or pelvis. [1]
The spot may feel soft and shift when you touch it. It may get bigger after your first exam, or the skin over it may start to feel different. People can mistake it for a normal bruise. [1]
Track how the lump changes
Tell your trauma team when the lump showed up and if it is getting bigger. Say whether the skin has changed color or feels different. A photo with the date on it can help show how things are going. An ultrasound, CT scan or MRI may give a clearer picture of the fluid and how far it reaches. [1]
Are you having surgery for a broken bone nearby? Then the surgeon needs to know about the swelling. It may change the plan for the wound and for preventing infection. [1]
Ask what each treatment is meant to prevent
A small, new lesion may be treated with compression and close watching. Larger pockets may need to be drained or need an operation. So may ones that linger, get infected or put the skin at risk. No one treatment fits every lesion. Ask if your plan deals with both the fluid and the space where it gathers. Find out how your team will check whether it comes back. [1]
Do not keep pressing on the lump or try to poke a hole in it yourself. [1]
Warning signs on the skin and in your body
Get checked soon if the area grows fast or turns hot or very painful. The same is true if it leaks fluid or the skin turns dark. A fever, or feeling sick while the lump is changing, also needs a doctor’s attention. [1]
Questions for your trauma team
- Is this an ordinary bruise or a deeper pocket of fluid?
- Will it change how my nearby fracture is treated?
- How will we tell if it’s shrinking or coming back?
Photograph the lump with a date
Snap a dated photo of the swelling. Tell your doctor if it keeps getting bigger. [1]
Sources and further reading
This article is general education from orthopedic trauma and wound care. Many swellings turn out to be ordinary bruises. Still, an area that grows and feels full of fluid after a hard hit needs an exam to find the cause.
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