Bleeding
The rash usually causes itching, and when you starch it, it results in the breakage of the skin. The blood starts to come out from the damaged skin area, and it also increases the chances of bacterial infection, in which case the situation can get worse. Other than that, if the blisters are formed, and the blood is filled inside them then punching or popping of those blisters will also result in bleeding of the infected area.