Can a blood clot form after getting a bruise and what signs do you look for?

I tripped over a baby gate in my hallway and fell and all my weight landed on my arm/elbow. Within about 10 mins it swelled tremendously and was deep blue/purple and I would say the swelling was very fast (like flat to completely swollen in less than 2 minutes and like I had a lemon on the side of my elbow). Anyhow, after xrays I had no broken bones. But, after 2 days the bruise's blue spots started to lighten ( but still a dark blue/purple) and in the center of the bruise (it had been black/purple) instead of lightening to a yellowish color like I have seen in the past, it is becoming an even darker red. What would it look like if I had a clot form and what would the signs be? I was very sore after the fall like you would expect, but now I have had dizziness when bending over and feel better but still getting light headed walking around a bit?

Its rare to get a blood clot in your arm, and it usually not caused by trauma. Blood clots are formed when people are at increased risk due to immobility, hypercoagulability, and vessel damage. You are at increased risk if you have any of the following risk factors:
1. recent surgeries or immobility
2. long plane rides or car trips
3. active cancer
4. genetic hypercoagulable states (you would probably already know if you had these)
5. taking oral contracepetives
6. high cholesterol levels
7. high blood pressure
8. certain other medications

Damage to the vessel is usually not from falling. It is frequently from inner vessel wall damage due to high cholesterol and high blood pressure, not from outer wall damage of hitting your arm.

Anyway, on the off chance you have a blood clot the only signs you would have is red, swollen, tender area (along with the risk factors already mentioned). A blood clot would NOT give you dizziness or lightheadedness unless that blood clot dislodged and went to your lungs. If that was the case you would be very short of breath and have some chest pain and a fast heart rate. If that is the case go immediately to the ER.
Anyway, a blood clot is diagnosed mainly clinically at first, and if suspicion is high then there are certain tests the doctor can have done. One of those tests sometimes done on an outpatient basis is a blood test. If the test is negative and the suspicion is low it can rule out a blood clot, however if it is positive it doesn't necessarily mean you have a blood clot, just that more tests need to be done. If he thought you were at high risk he would perform an ultrasound.

That said,you are still at LOW risk to have a blood clot, you probably just have a bad bruise. HOWEVER, you are at risk for something known as compartment syndrome. This is also usually in the leg but happens occasionally in the arm. It happens when an injury causes so much damage that it prevents proper lymphatic and blood return. Signs are a extreme pain at rest, tingling sensation, cold hand, and an arm that is swollen and tight. Usually a decreased pulse further down the arm/leg. This is a surgical emergency. If you think the swelling isn't going down, and you start to have INTENSE increasing pain, especially if you notice a decrease in your peripheral pulse or a tingling in the arm - go IMMEDIATLY to the ER. Your chances are small that this would happen - but if it does it is very serious.

Don't take my word for it, take a visit to your family physician so he can take a look at it (especially if it's not improving). I would save the ER visit for a more serious injury though (unless it worsens or you get any of the signs mentioned above)

GOOD LUCK,
Mike

(feel free to give me the "best answer")

First let me say I'm not a doctor. That being said, a blood clot usually gives you pain in the area it's in; the type of pain that makes you feel like you want to rub that area- which is a bad thing to do. It may also feel warm to the touch, but warmness can also be due to other factors, too. Your best bet is to see a doctor. Blood clots can be very dangerous. You can't "see" a clot, as far as I know. Good luck.

If you had it examined by a doctor, I wouldn't worry about a blood clot. Blood clots usually occur within a vascular structure (vein or artery) not a bruise. And if it's not fractured, then you're not going to get a clot. It's just a bruise....bleeding under the skin and muscle. It will turn different colors as it heals and will spread a bit also. And it will hurt. You will just have to wait for it to heal. Your muscles probably got pulled but you're being a "baby" yourself about the lightheadedness. It's got nothing to do with the bruise....or did you hit your head too? Be glad you didn't break anything.

Some bruises go red instead of yellow beacause there is still some blood in there to be reobsorbed. It's nothing to worry about. As for the dizziness/lightheadedness, it's probably not related since you said you felll on your arm/elbow.