I had 2 surgeries on my left wrist several years ago and since then I have developed recurrent hives only in one spot on the inside of my left forearm. Completely random. I have not been able to identify any triggers and like I said they literally only show up on the inside of my left arm between the crease of my elbow and about 4 inches from my wrist. The dermatologist told me to take Citrazine and if one pill doesn’t work take two. He said he had no idea what was causing it. I never had hives at all prior to the surgeries on my wrist so I know it’s not a coincidence. Something about the surgery has given me chronic hives years later but only in that one spot.