You seem to be suffering from urticaria. It can occur due to varied causes. One could be the thyroid antibodies which can be detected by a blood test. Other common causes are medicines, food, changes in temperature, reaction to any metals or jewellery. Has there been a change in any of these recently? If yes, avoid them in future. As of now, be on a bland diet. Avoid sour, spicy food. By the way, which auto immune disease are you suffering from? For immediate relief, the doctor can give you an injection of anti histamine and steroid. As you have already been started on oral steroid, continue and taper it as per your consultant s advice. Also get a blood test done to check for your counts and IgE levels. Hope this helps