Psoriasis, also known as “psoriasis”, is a common and recurring chronic inflammatory skin disease. Although a lot of research has been done on this disease at home and abroad, the cause and pathogenesis of it is not yet fully understood. There are several theories: 1, genetic factors: the disease often has a familial history of morbidity, there is a genetic predisposition, generally considered to be about 30%. Currently, susceptible regions are found on several chromosomes. 2, immune factors: psoriasis patients with excessive skin inflammatory-immune response, increased circulating immune – effector T cells, to minor damage can induce cascade inflammatory response. 3.Infection factors: streptococcal infection is related to the onset and prolongation of psoriasis, Staphylococcus aureus can aggravate the skin lesions, fungal and viral infections are inconclusive. 4, endocrine factors: psoriasis often has a tendency to improve significantly during pregnancy, and there is a tendency to aggravate after delivery. 5, neuropsychiatric factors: the skin is one of the organs of expression of the internal mental activities of the human body, and psoriasis belongs to a kind of skin psychosomatic disease in a sense. Special life events may affect the nervous, endocrine and immune systems. 6.Life habits, drug factors and environmental factors: dampness, infection, alcohol consumption, medication and mental tension are the main risk factors for triggering psoriasis. Drugs that may induce and aggravate psoriasis include: β1 receptor blockers such as metoprolol, etc., non-steroidal anti-inflammatory drugs such as acetylsalicylic acid, ibuprofen, meloxicam, anandamide, etc.