All over the body suddenly red rash itching

For urticaria, caused by allergies, can eat some anti-allergic drugs. Drug allergy is drug eruption, but also can be repaired with drugs. Allergic rash due to contact or consumption of certain allergens or environmental changes such as hot and cold stimulation. Systemic itching rash to prevent and allergens too close, can not be scratched by hand, to be cleaned normally to determine hygiene.