2 years ago I went away for 4 days to New Hampshire for vacation. During the trip I developed a rash on the back of both my hands. It had very distinctive boundaries over the backs of my fingers and part of my hands. It was very red, slightly raised, mildly itchy, hot to the touch and blisters developed within several days. It felt almost like a burn and went away in around 10-14 days. I have had poison ivy previously and do not think this is what I had.
Now 2 years later, went away to New Hampshire for 4 days again. Have not had any incident or occurrence since last episode in New Hampshire (first time rash ever presented was in New Hampshire 2 years ago). Same rash develops again on back of hands and in very very similar pattern.
I went to a dermatologist and was told they thought it was an allergic reaction to the sun. I do not think this is the cause. I play basketball and tennis outside several days a week all summer and never had the rash. Any idea what could cause this?