cant figure out what skin problem this is

so my friend he has this condition which we all cant figure out. each time he arm or face or any part of his body gets scratched or even pressed, it starts to burn him and eventually that part swells up and the skin raises like a little lines.and it takes atleast 20 mins to rise slowly then eventually goes back down. he used to scratch it cause its itchy but now he controls. scratching makes it worse and it spreads. he tried it once that he wrote on his arm with a pen. it rose up and became as if it was embossed on his arm. does anyone have any idea what this is? ive searched through alot of diseases i cant match it up to anything =( please help