Itchy and red body, consider the following diseases: 1, hives, the disease may be due to sunlight, ultraviolet radiation allergy or cold stimulation, oral allergy to foreign proteins, such as protein powder, beef, mutton, chicken, duck, goose, dog meat, shrimp, crab, scallops, bird’s nest, shark’s fin and other seafood and allergies. It may also be caused by serious medical disorders, such as hyperthyroidism, hypothyroidism or metabolic diseases such as diabetes, hyperlipidemia, and malignant tumors. It may also be caused by infectious factors, such as Helicobacter pylori infection.2. Erythema multiforme, which may be caused by infectious factors or drug irritation, should be avoided during treatment.