
A blood clot is a clump of material your blood makes to plug up the bleeding from a cut. Blood clots are made of special clotting substances and platelets (very small blood cells).
After a cut heals, other substances in your blood dissolve the blood clot. Your blood has many different substances that work together to make and dissolve blood clots.
What is excessive clotting?
Excessive clotting is when your blood clots too easily or too much. Blood clots are good when they stop bleeding after an injury. But blood clots that happen when you're not bleeding can be dangerous.
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Blood clots may form in your blood vessels when they're not supposed to
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The blood clots may make your arm or leg swell up or cause a stroke or heart attack
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Sometimes, clots break loose and float through your bloodstream and block blood vessels in another part of your body
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Doctors do blood tests to measure the clotting substances and platelets in your blood
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You may need to take a blood-thinning medicine to prevent clotting
What causes excessive clotting?
Usually, there's a problem with one of the clotting substances in your blood:
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Sometimes, one of your clotting substances is overactive
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Sometimes, one of the substances that dissolve blood clots is underactive
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The problem is usually something that runs in your family
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Sometimes, an illness such as cancer or a problem with your body's immune system makes your clotting substances too active
Other factors increase the risk of excessive clotting:
What are the symptoms of excessive clotting?
You don't usually have problems until you're an adult.
If you have excessive clotting in your veins, you may have:
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Leg pain and swelling from a clot in your leg (deep vein thrombosis)
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Shortness of breath or chest pain from a blood clot that travels to your lungs (pulmonary embolism)
If you have excessive clotting in your arteries, you may have: