What's with the red bumps all over?

If the skin red pimple performance is rapid onset, rapid resolution of erythema, wheals, itching, it is likely to occur urticaria. Urticaria is due to the small blood vessels of the skin mucosa expansion, and permeability increased and showed a localized edema reaction. Normal in a few hours to 24 hours can resolve, but easy to repeat attacks, and can last for several days to months. The cause of this disease is complex, some patients are difficult to identify the cause. Common causes include food or food additives, inhalants, infections, drugs; physical factors, including mechanical stimuli, cold, heat, sunlight, and insect bites; mental factors; and endocrine factors.