Hi, my 11 year old son experienced a rash 2 days after playing outside in the snow. Where snow touched his skin, he developed redness and lumps under the skin. They bumps were sore, and lasted about 4 days. When they finally went down, the skin was left with a dark spot. The doctors have no idea what caused it. I did the cold test, for cold urticaria, and an ice cube left on his forearm for 3 minutes, developed into a sore raised red mark 2 days later, and its taking about a week for it to subside. Again, leaving a dark mark on his skin. I m terrified, I don t know what it is. The doctor sent him for blood work yesterday, but I am hoping you may have some insight into this. Thank you.