Hi Dr. Grief, My 15 yr. old son has been developing itchy rashes off and on for a couple of weeks. They mostly appear as a long thin welted lines. He says that if he scratches, it seems to spread. Yesterday, when this happened, small round raised bumps appeared on his inside forearm as well. Antihistamines help. As far as we can tell, he has not used any new products or eaten any new foods. It seems to appear out of nowhere for no reason. Thank you for any advise. Sharon