How is erythema caused?

Under normal circumstances, the causes of multiple erythema are probably the following: 1: infection accounts for about 90% of clinical infections, including virus, bacteria, mycoplasma or fungi. 2: drugs: about 10%, mainly sulfa, penicillin, barbiturates and antipyretic analgesics can also cause multiple erythema. 3: physical factors: cold, sunlight, radiation, etc. 4: Rheumatic diseases or autoimmune diseases can also cause multiple types of erythema, such as lupus erythematosus and inflammatory bowel disease;6: Hematological diseases and malignant tumors can also cause multiple types of erythema.