About a month ago I came down with a viral infection and became dehydrated. When I was sick whenever I would start to get hot my entire body would itch and feel prickly. It felt similar to when I've had an allergic reaction to a drug. I would take a couple benadryl and the itching would stop. I haven't had any med changes in over 3 months, so I doubt this is anything "drug" related. But lately whenever I start to get hot I get that itchy prickly feeling again and it just keeps getting worse. I have to get out the ice packs and cool my body down and the itching/prickling has really become bad. I have been staying well hydrated and this only happens when I start to exert myself or begin to sweat.