Just a few guesses here: Do you use wash dishes or clothing with your hands? You could have an alergy to the soap or detergent........ Do you work with any chemicals? Do you use a lotion or cream on your arms and hands, or hand soap with a scent? I had chronic hives, and while being tested, was found to be highly alergic to what they mixed the alergens with for the test! (AFTER months of testing!) One more guess: do you sleep with your arms touching the bed covers? Maybe something you wash them with is causing the problem! I hope you get the answer quick. Ken