What is the reason for the eruption?

Skin out of the rash is allergic symptoms, clinically known as artificial urticaria. When the skin by friction, stimulation, there will be purple and other conditions, similar to "out of the rash." It is best to go to the hospital dermatology department to see a doctor, follow the doctor's advice application cyproheptadine, chlorpheniramine maleate tablets and other antihistamine treatment, combined with immune regulators.