What Causes Large Bumps On Fingers?

I have had these large bumps on three of my fingers and 8 of my toes for 2 weeks now and they aren't clearing up. They hurt with ice and itch with moisture and heat. It was first diagnosed as MRSA but didn't respond to Bactrim. The dermatologist I saw said he strongly believes it is not an infection.

I do have raynaud's syndrome but we are unsure if that is related. He ordered blood work which won't be ready for a while. What might it be?

The blisters range in size from a pea size to a dime. The surrounding area is also swollen slightly and half are red, half have a purple center.