Can Bruises Cause Serious Blood Clots?

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Can a Bruise Cause a Serious Blood Clot?

Bruised legby James Hubbard, M.D., M.P.H.

I see this fairly often. Someone comes in with a whopper of a bruise, maybe with a lump, and they’re afraid it’s a blood clot. In a disaster situation, you’re likely to get some bruises, but you won’t be able to come see me. Should you worry?

In short, probably not. You do have clotted blood, but there are blood clots and there “blood clots.” In fact, if your blood doesn’t clot, you could bleed to death.

Bruise-related clotting happens in tissue outside the blood vessels. That’s where the bleeding occurred. What you’re really worried about is a deep-vein thrombosis (DVT)—a clot that forms inside a deep-in-the-tissue vein and can break off and travel to the lungs. DVTs are different, serious, and sometimes lethal.

So a bruise isn’t a serious blood clot. However, can a bruise cause a serious blood clot? No, but the hit that caused the bruise can—though that’s rare.

If the trauma that caused the bruise injures a large and deep-seated vein’s wall, it could make conditions right for a deep-vein clot to form. These veins are deep in the tissue and have to be hit just right. Compared with the number of bad bruises people get, this is rare as hen’s teeth and has to do with the injury to the vein’s inner wall. The bruise to the soft tissue is incidental.

How Can You Tell Whether You Have a DVT?

Even doctors can have a tough time telling whether you have a DVT. Sometimes one forms with very few outside signs. But suspect it if your arm or leg swells and becomes painful—trauma or no trauma.

Since DVTs often form in the calves, one test is the Homans’ sign. Simplified: You lie down, toes up. The doctor takes hold of your relaxed foot’s sole and quickly flexes your foot, pushing your forefoot back. Significant pain in the calf points toward a deep-venous blood clot. But positive Homans’ sign or not, If the doctor is suspicious, he or she will order a special type of ultrasound test that looks inside the veins to find out for sure. If you have DVT, you’ll be started on a blood thinner.

If you can’t get medical help, your best bet for a swollen, red extremity is to keep it immobile, elevate it at heart level or above, and apply a moderate amount of heat to the area. Get to a doctor as soon as you can.

So What If You Have a Bad Bruise That’s Bothering You?

For a bad bruise, treat it with RICE. That’s

  • Rest
  • Ice. Use a commercial type, a frozen bag of vegetables, or ice in a zip-close bag. Put a cloth between the ice and skin. Use it for something like ten minutes on, ten minutes off, repeat.
  • Compression with an elastic bandage—firm, but not to tight. Loosen as needed.
  • Elevation at heart level or above.

Unlike with DVT, using the extremity poses no threat if you just have a bruise.

What If Only the Bruise Is Swollen?

Sometimes, the area bleeds enough for blood to pool in the soft tissue. If this happens, a localized area will be swollen, even baggy. This is called a hematoma. Other than the RICE, leave it alone. It may even shrink to a smaller, firm spot—a blood clot. But it’s outside the blood vessels. To try to drain it outside of a medical facility is to risk infection.

Don’t be surprised if a large area of discoloration shows up days later. It may even travel with gravity down to areas not bruised. That’s a good thing. The blood from the hematoma is spreading out and will be absorbed.

Bottom Line?

Bruise or no bruise, if your extremity swells or hurts, see a health-care professional. You never know. But don’t get too concerned with some marble-sized knot after a fall.

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  • Dan

    I cannot believe a doctor who has no idea id the posted does have a blood clot or not has advice him to raise his lef and keep it immobile. If it were to be a clot that is the last thing you want to do. Clots can form when people are immobile hence a lot of hospital patients suffering them. Like you said though doctors can have a hard time diagnosing them. When I went to 3 doctors and a & e with nausea, cramping in my calf and dizziness after having surgery I was told *not to worry you are young you will be fine *it was hot yesterday its probably heat stroke (This was in Wales in February!! it was freezing), one just looked at my leg and said no you don’t have a clot otherwise it would be big and swollen and you would be coughing blood, erm no that’s DVT and if I had a clot and was experiencing the symptoms the doctor should have taken more time as its their job to prevent DVT happening a blood clot is serious an medical scans or tests should be ordered if ever a person is feeling these symptoms. Seriously bad doctors who are set in their ways because they have been doing it for years are killing people.

    • James Hubbard, MD, MPH

      Dan, if a person has a deep blood clot in the leg (DVT is same thing) then, indeed, keeping the leg immobile for a few days is the thing to do. The main danger of a blood clot, DVT, is that a small part of the clot will break off and travel to the blood vessels in the lungs.

  • rinnaray

    I want to see if you think this is normal with a few questions about how bruises move. If it were me I would be at the Dr. But husband’s different he feel off a big truck hit very hard said he was OK. That night inspecting had two small scratches on back of his thigh an a light sign of bruising. Next day was very dark normal looking bad bruise with some veiny lines on the side. No pain to the touch. A week later over night the bruise is yellowish mostly but where the vein things were is super red and blackish bruise an is now very sore after he pressed an said didn’t hurt. The first 1 was like a LG smushed circle an this is tall an slim is puffy. Do bruises usually turn yellow when they or the blood moves an I knew they could move down but straight over to the side?

    • James Hubbard, MD, MPH

      Rinnaray, many bruises turn yellow with time. Also new colors or evidence can occur as the blood for deep bruises comes to the surface. However, the pain is getting worse, or signs of infection, like increased redness or streaks develop, that could be a sign of infection and needs to be checked out.

  • shay vogler

    I was playing basketball and I fell and hit my hip hard on the concrete-like-floor. It wasn’t too bad of a bruise at first. Then I woke up this morning and there is a brownish color bruise (very small to see) around the purple, red, bruise. it’s all one area and it only hurts if I hit it. Should I be worried of a blood clot?

    • James Hubbard, MD, MPH

      Shay, I can’t diagnose individuals. I would suggest you get your parents or coach to check it. All my general information is in the post. Certainly any bruise can turn all sorts of colors and, if it’s deep, spread out with time, and with gravity, travel down the thigh.

  • Joseph

    I had a scab took it off with derma tend it formed a scab then the scab fell of there was a hole the new skin began to grow it was red then turned purplish and blackish but lighter is it a bruise

    • James Hubbard, MD, MPH

      Could be, Joseph.

  • Gayla

    Just this morning I was helping a lamb nurse its mother, when the mother quickly turned and stepped on the inside part of my calf. It is hard as a rock, has a strange sensation, swollen, painful and hard to walk. Looks like half a grapefruit on the side of my leg. Any suggestions??

    • James Hubbard, MD, MPH

      Just the RICE part of my post. Otherwise, if you think it’s injured worse than a bruise, see a doctor.

  • Brad

    Excellent Blog!! Great job!

    • James Hubbard, MD, MPH

      Thanks, Brad.

  • Shayla Striffler

    I got hit in the shin with a hammer, and the bruise eventually wrapped all the way around my calf with a 4 inch purple band. Do I need to worry? It doesn’t hurt, just looks bad.

  • Jess

    A few years ago I fell on my back on wooden floor. Under my thigh I got a huge bruise it was blue, purple like any bruise would look like but had a red color as well and I wasn’t sure if I was bleeding inside instead of out and the whole area was swollen. The bruise was as big as a grapefruit and was difficult to sit for a few weeks. Several months later the color went away but I always had that swelling and after 6 years I still have that swelling and also if touch that area at first it feels like I have no sensation there at all but if I touch it harder it starts to hurt. Because I was a teen I didn’t know any better so I didn’t get it checked out because I thought it would go away even though it hurt really bad for the first few months.
    What could this be? After 6 years I still have this swelling from an old fall.

    • James Hubbard, MD, MPH

      See the post part of “What if bruise is only swollen.” But a doctor would have to check it to see if it’s trapped blood or fluid or something else.

  • Busy Grammy

    Dear Doctor Hubbard,

    About three weeks ago I bruised my upper inner thigh. I was stepping over a stationary piece of corregated sheet roofing, the old heavy pieces and which is used as a retaining wall. As I stepped, sand gave way and I fell within a hole with my leg straddling the roofing. Hope this makes sense. The bruising was intense, but the color is almost gone, yet now i feel a “strand” of little balls, like a strand of pearls, some larger, some smaller, in somewhat of a line, perhaps following the impressions of the edge of the sheet when I hit. There is no pain at all. Any worry of blood clots there?


    • James Hubbard, MD, MPH

      I can’t diagnose or give specific opinions without an exam. If you’re worried you should see a doctor. And read the post carefully. Deep vein bloods clots (the dangerous kind) are usually pretty deep in the tissue, often associated with pain and swelling although that can vary. But, as I wrote in the post, sometimes it’s hard for even a doctor to tell without an ultrasound.

  • Sherry H.

    I fell about 2 & 1/2 months ago and bruised my butt, calf and ankle really bad. I went to. The urgent care the next morning because I thought that I hsd broke my tailbone….but I was told that I just had very deep bruises. Now if I push on my calf it still hurts but no to bad. But my ankle the one that had the least of the bruising has a little knot that still hurts. Is this normal? I won’t be ever worried about it but I’m getting ready to have surgery next month and am worrying about blood clots now. Should I go to my primary doctor and have an ultrasound done before I have surgery? Or is it still just healing?

    • James Hubbard, MD, MPH

      See a doctor and have it checked out for peace of mind if nothing else. From what you describe it doesn’t sound like anything dangerous but it’s bothering you, you’re worried and it’s had plenty of time to heal. And, of course, all I can do is speculate without an exam.