Hi Doctor. Three months ago, I got this strange burning sensation on my calf. The burning gave way to itching and welts under the skin appeared. Eventually the lumps turn hard and come to sort of a head. Each bump then gets a small liquid filled blister. Scratching them breaks them open causing them to join together and form one big oval shaped blister. The skin looks like it has been burned and is red and swollen. I have had this happen twice previously, once on each leg in the same location, two months apart to the day. Now two months later another is starting to form again. Incidentally, each blister/scab has left a scar. The scab is basicaly superficial and tends to lift off in one piece extremely easily approximately one day after forming. In the past i have found i am allergic to perfume, hair products, some cleaning products,latex (just recently)