A lot of red pimples rose suddenly on the body very itchy how be to return a responsibility

The body suddenly had a lot of red pimples very itchy, consider urticaria, urticaria is caused by a variety of reasons for the expansion of small blood vessels in the skin mucosa and permeability increased and showed a kind of edema reaction, the specific cause of the disease is not clear, may be related to the following factors: First, food factors, eating fish and shrimp, seafood, peanuts, tomatoes, food additives and so on can cause allergies. Second, caused by drugs, many drugs can cause allergies, such as penicillin drugs, sulfa drugs, antipyretic analgesics, etc. Third, infection factors, including bacterial infection, viral infection, parasite infection, fungal infection, etc. Fourth, mental factors, such as mental stress can cause allergies. Fifth, physical factors, sunlight exposure, friction, pressure, etc. can cause allergies. Sixth, caused by diseases, such as systemic lupus erythematosus, rheumatic fever, malignant tumors, etc. can cause urticaria. Other factors, too many allergens in the environment, such as pollen, dust, etc.