I have had red, itchy patches suddenly covering most of my body today. Each one starts as a red pin prick , the blisters white then expands into a red, itchy, hot patch with raised bumps about 7 cm long. In the last 2 hours alone around 20 patches have appeared covering everywhere except my lower legs. I m really worried. Can you help. I m a 44 year old female, in good health. 5ft 5in height and 11.5 stones in weight.