I am going through this right now.. it has happened before last year when I crochet for long periods.. I have only been using Bernat blanket yarns lately.. I get the red hot rash more on my right forearm than I I do on my left.. only my forearms.. nothing on my hands at all .. I have angeodema which is unknown swelling and hives but this is different it almost feels like a chemical burn.. mine isn’t itchy like my normal hives are.. I took 30mg of Reactine and cortisone topical cream and it hasn’t let up.. it is the weirdest thing..