Psoriasis, a skin disease prone to recurrent attacks, is mostly caused by environmental humidity or temperature differences. Without timely treatment, the disease can involve any part of the body. Experts said, the environment factors really is one of the symptoms of psoriasis, psoriasis has obvious seasonal characteristic, because it is related to climate, in the winter because the temperature become low, a person's skin to become dry, ultraviolet intensity is very weak, these all make the psoriasis are more likely to happen during the winter, and in summer, temperatures and the sun ultraviolet ray can effectively protect the skin.

        In addition, the current urban environment is directly deteriorating, and the air quality is getting worse and worse, which is also an important incentive for psoriasis. General population is more dense city, the higher the incidence of the disease, so for the long-term living in a fast pace of people, must pay attention to personal hygiene and clean, keep a good living environment, so as to reduce the chance of being infected. According to the survey in 1985, the incidence of psoriasis was higher in the north than in the south, and higher in cities than in rural areas, which was related to temperature, sunlight exposure, production, labor and living habits. Compared with the rural areas, there are some unfavorable factors, such as industrial pollution, fast pace of life, strong competitiveness and heavy psychological burden.