Psoriasis is a chronic, relapsing, inflammatory, systemic disease induced by a combination of genetics and the environment, thereby inducing an immune-mediated disease. The exact etiology and pathogenesis of the disease have not been elucidated, and young people suffering from psoriasis are considered to be caused by a combination of genetic, environmental and immune factors. 1. Heredity: Epidemiologic data and genetic studies have shown that psoriasis has a genetic predisposition, and a number of psoriasis susceptibility loci and psoriasis susceptibility genes have also been found. 2. Environment: Environmental factors play an important role in triggering or aggravating psoriasis, or making the condition prolonged, including infection, mental stress, smoking, alcoholism, trauma and certain drugs. 3. Immunity: abnormal activation of T-cells, infiltration in the epidermis or dermis is an important pathophysiological feature of psoriasis, which indicates that the immune system is involved in the occurrence and development of the disease. It is suggested that young psoriasis patients should go to regular hospital dermatology department in time for clear diagnosis and standardized treatment according to the doctor’s instructions.