Brief Answer:
Could be due to blood clot

Detailed Answer:
Hello,

Thanks for posting,

More often, bruised hands are due to blood clot in capillaries that supply the hands hence preventing proper blood supply to the subdermal and dermal tissues of the hand. This bruising can become permanent (scar) if it does not spontaneously resolve itself.
I would have loved to get a picture of the bruise and see if you might be referring to another type of lesion order than bruising that could perhaps be due to an infection such as fungi or virus.
Conditions such as Blunt trauma, Coagulopathy, Anticoagulant medications, Bacterial septicaemia (see Blood infection), Fracture, Hand injury etc could directly or indirectly be responsible for bruising hand.
You will require some blood work too in order to find out if you are suffering from any diseases condition that might be responsible for this.
Note that, if the bruise is not changing in size or occurring in other areas of the body, then it is possible that it is nothing serious you need to worry about.

Hope this helps and wish you the best.
Dr. Nsah

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Brief Answer:
Looks like an ecchymosis

Detailed Answer:
Hello XXXXXXX

That lesion looks like an ecchymosis which is a subcutaneous purpura larger than 1 centimeter or a hematoma, commonly, but erroneously, called a bruise. That is, bruises are caused by trauma whereas ecchymoses, a type of purpura, are not caused by trauma.
In your case, it is unlikely due to trauma or any injuries. An autoimmune diseases is where we should start looking (important to rule out conditions such as lupus). But looking at the lesion it seems benign and hardly will be associated with any conditions as I mentioned. Just give it a couple of days to clear off on its own and if it persist or reoccurs then that is an indication to see a doctor for full physical exams, blood work etc.


Hope this helps further.
Dr. Nsah

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