Modern studies have suggested that psoriasis is an immune-related chronic inflammatory skin disease based on a certain genetic background. Psoriasis is not a blood disease. The so-called blood disease refers to the abnormal red blood cells, white blood cells, platelets, or hematopoietic system abnormalities caused by the disease. Psoriasis has nothing to do with this, its problems mainly occur in the epidermis, dermis, keratinocytes, and outside the blood vessels. People often mistake psoriasis for blood disease, mainly because they confuse the blood disease in western medicine with the blood syndrome in Traditional Chinese medicine, and mistake the traditional Chinese medicine concepts such as insufficient blood, heat in blood, stasis in blood, etc., for the presence of poisons in the blood, lack of blood, heat in the blood, blockage of blood vessels and so on.