Last night I suddenly had strong cramp-like pain in my left wrist just below the palm on the side furthest from my thumb. Looking at it I could see what looked like a swolen vein, like the blood just couldn't pass & was stretching the vein. In relation to the rest of my hand/wrist that location felt quit a bit warmer. The pain lasted approximately 20 minutes then was gone, only hurting when the location where the bulging vein had been was touched. Now today, I woke up with a bruise in the exact location where the pain & vein had been, and it is still painful to touch. This has happened at least 2 other times that I can remember, both times on the other side of my wrist at the thumb joint closest to my wrist. All of these occurances are random and never following excessive use or injury of any sort, it's just out of the blue. I'm a bit concerned because the last time that it happened was just a few months ago, it seems to be getting more frequent, in the same wrist. Yes, I do type for my work, I won't totally rule that out as a cause, but what is it called, is it harmful, and can I prevent further events?