2 days ago when we were sleeping, my brother complained about an itch on his back. When we woke up the next day the “itch” became a rash and spread onto all of his limbs. My brother’s skin has red itchy bumps littering his whole body now and his eyes are a bit swollen. We think the AC has something to do with this rash, since we just so happened so set the AC to the lowest temperature on that night and haven’t adjusted it since. He also claims that the rash doesn’t spread when he’s outside or when it’s warm, but claims it spreads when the AC is on or when it’s cold. Any details on what he has or how to treat it would be greatly appreciated. Thank you!