I'm 72 with long term hypothyroidism which I manage ok but have a wonky thermostat and can not stand the heat. With this recent bout of warm weather I have broken out in an itchy rash on my lower legs, my ankles have swollen and my elbows now seem to be swelling. I have no pain other than itching. Is this a symptom of my hypothyroidism? My gp has no answer and has prescribed antihistamines. I have not been bitten by a tick. Any clues please?