Hi, I had been suffering from this condition for almost 4 years. This happens when I scratch myself.. even lightly, after a few mins, the scratch marks will be swollen and red.. very visible. At first I thought maybe it's something to do with my fingernail so I tried scratching it deliberately with somthing else... eg. a ruler. The same thing occur to me? I consulted a few doctors and they said it's nothing to worry about. Most probably it's my diet or something. But I never had this problem before in the past until 3-4 years ago!