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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  • anon

    Can I ask I’m on Warfarin was given lyrica and had bad fall. Bruising raised and sore. Very bad health probs including lots of clots in lungs before. What you think please

    • James Hubbard, MD, MPH

      Bruise can be risky on blood thinner. If it’s bleeding or swelling a lot, you should get seen or call your doctor tonight.

  • Shane Freehauf

    I don’t know if this thread is still active but I got a nasty big bruise on the outside of my thigh by falling off a ladder. It’s
    turning all different colors now. It has been 4 days from the time I fell and now my bruise has some dark, purple lines going north/south through my bruise. Any idea what this is?

    • James Hubbard, MD, MPH

      Not really sure. The big worry would be if the area was getting progressively more tender.

      • erica

        What if you don’t injure where your vein is and it bruises? I was swimming earlier and out of nowhere the varicose vein on my right calf started hurting(which in the past it stops after a few hours) so we took a picture of it swelling and what it looked like but about 6 hours later it’s still hurting so i pull up my pant leg and it’s there’s a bruise the size of a clenched fist! Everytime I’ve gone to the doctor they said”take aspirin and wear tight support hose” but now? I don’t know.

        • James Hubbard, MD, MPH

          Any vein can leak (essentially a bruise). Sometimes they can do it without cause. Sometimes some nontraumatic activity, such as swimming, could do it. If this happens occasionally it’s nothing to worry about. If you have frequent bruising or easy bleeding it should be checked out. With a large bruise like yours it should be checked out. Maybe you should check some blood tests if this hasn’t already been done.

          • erica

            When I had my insurance, my doctor told me blood cots were too rare for me to have one so we ignored it. It started out like it usually does. And turned into a huge bruise after like 4 or 5 hours. Legally, nobody can tell me anything without seeing it but they can tell me “if” they were me they’d go to the ER because the clinics don’t have the Doppler to check for clots. I’m in the predicament where my boss doesn’t want me to come back to work til I get it checked out. But everytime I’ve pointed out my concern to a doctor, I was talked out of it and told “don’t worry about what it could be. To check would cost us both time and money and I’m sure you’re really not wanting all this trouble over what could be nothing. Take some aspirin, elevate your feet, and wear tight socks”.

  • soph

    I was cUght in a fight that broke out and was bitten very hard all though the skin did not nit break it’s has become a big hard lump under my skin,, the middle us red very saw and hit to touch should I be worried?? Thanks

    • James Hubbard, MD, MPH

      I can’t really give anything but general information and that’s in the post.

  • Denise

    I fell recently on some ice. I seem to have fallen directly on my varicose veins causing bruising and swelling. Now 5 days later the vein directly behind my knee is hard and there feels like there may be a lump developing. I am somewhat concerned because I had a blot clot in this leg about 5 years ago. The bruising seems to be fading but I still feel the Pressure from the vein. Can I wait a few more days to see if the lump goes away or should I see my Vascular Doctor now ?

    • James Hubbard, MD, MPH

      I’d call the clinic and ask.

  • selena

    I develop a bruise on my back with is a lump out of no where but i do have blood clots in my right leg and my lungs. I know i bruise from the lovenox shot but i have one my leg and now on my back should i call my doctor ?

    • James Hubbard, MD, MPH

      Sounds like this is the first time you’ve had this much bruising from the shot so, yes, I’d check with your doctor.

  • Sage

    Super post, I’m an RN who wondered if a severe bruise could cause a DVT,
    and you answered the question. Was wondering about it because I’ve had 2
    patients who have developed DVTs after falls resulting in bad
    hematomas. At first glance, it would kinda make sense, but thinking
    about it after your explanation, maybe not.

    • James Hubbard, MD, MPH

      Thanks, Sage.

  • Preston

    This is my current bruise. Do have some swelling but no heat.

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  • Mary

    Thank you so much, doctor. I tried searching the Mayo Clinic’s website re bruising and blood clots; and received a much better and concise answer from you that was readily understandable. I liked the “hen’s teeth”. That was cute — reminded me of Gramma. Thanks again.

    • James Hubbard, MD, MPH

      Thanks, Mary.