What's the name of the autoimmune skin condition that makes your skin welt with just a little scratch?

When you even scratch yourself lightly (like to scratch a light itch) Your skin welts up for 20 minutes or more. It%26#039;s an autoimmune condition. First correct answer will get the 10 pts. I can%26#039;t remember the name of it, and I want to research it more. (my brother has it)Thanks!|||Are you talking about dermatographia? I%26#039;ve seen it before when I worked in dermatology - you can %26quot;write%26quot; on the skin with a fingernail and the skin will flare up so you can read what you wrote.|||the symptom sounds more like anaphylaxis or simply some form of an allergic reaction. this can be relieved by 10mg claritin. [no prescription needed!!]|||I%26#039;m not sure if this is right but my mom has Lupus and her skin welts with scratches and with direct sunlight. You could be thinking of something different though.