I have low platelets and sometimes this happens.
I've had this condition a very long time.
Platelets are what helps us to clot normally.
I can get bruises like that when my counts are down.
Sometimes certain medications can cause low platelets ... probably dosage related.
If you are taking something that can cause this...I would inquire about a reduction in dosage.
If you continue to bruise, you might want to get a CBC.
You are right...vitamin K can help with bruising!
I think some people just bruise easier than others...might not necessarily be any "condition" at all.
My multi has a nice amount of "K" in it and on occasion, I'll take a little more separately.
I also rub arnica cream on my bruises. It does seem to help.
I have vitamin K cream as well. I use this now and then. I think it helps, but I think the arnica creme works better.
Oh...another thing that helps me with bruising is green leafy vegetables...especially juicing. Not blending...juicing, which removes the pulp.
Hope you get this sorted out and feel better.