Psoriasis, also known as “psoriasis”, is a common and recurring chronic inflammatory skin disease. In terms of age of onset, young adults are the most common. Most of them are winter type, but a few of them develop in other seasons. Because of its high incidence, easy recurrence and long duration, psoriasis has a great impact on patients’ physical health and mental health. Many studies have been conducted at home and abroad on the etiology and pathogenesis of this disease, and although some achievements have been made, no definite conclusion has been reached so far. There are several theories on the main causes or triggers for the occurrence and development of the disease, such as genetic factors, infectious factors, metabolic disorders, endocrine factors, neuropsychiatric factors, immune factors, etc., but the real causes and mechanisms of the disease have not been fully elucidated so far. According to the clinical characteristics of psoriasis, it can be generally divided into four types: common, pustular, arthritic and erythrodermic psoriasis. Psoriasis vulgaris is the most common type in clinical practice, and most of them have an acute onset. Initially, it is usually an inflammatory red papule, about the size of corn to green beans, and later it can gradually expand or fuse into brownish-red plaques with clear borders, surrounded by an inflammatory red halo, with obvious basal infiltration and covered with multiple layers of dry silvery-white scales. Gently scrape away the surface scales, then gradually reveal a layer of light red shiny translucent film, called film phenomenon. If the film is scraped away again, small bleeding spots will appear, which is called punctate bleeding phenomenon. White scales, shiny film and punctate hemorrhage are the clinical features of this disease. In the progressive stage, skin lesions appear at the trauma, called homomorphic phenomenon. 1.Pustular type: Dense sterile pustules of corn grain size appear on the basis of erythema. 2.Arthritic type: In addition to erythema and scaling, there are also manifestations of arthritis, with erythema and pain in the distal finger, wrist and ankle joints being common. 3.Erythrodermic type: often due to improper treatment, the lesions rapidly expand and fuse into a diffuse large flushed swelling, a large number of flakes, and the area exceeds 2/3 of the body surface.