The ancient Greeks believed that psoriasis was cursed by many gods and forced psoriasis patients to ring the bell to prevent infection. Among the known celebrities, Lin Biao, Stalin and Zeng Guofan all suffered from this disease. Zeng Guofan suffered from severe psoriasis and had to be tickled by the maid every night to fall asleep. He never recovered all his life. In the past, because there were more housewives and catering employees, it was once thought that it was related to the detergent they used to wash their hands. At that time, because the society thought psoriasis was contagious, in order to prevent guests from being infected by eating food containing dander by mistake, these employees would be dismissed by the restaurant. At present, it is generally believed that excessive life pressure leads to endocrine disorder of the disease-causing person, thus affecting the immune system of the body. Therefore, doctors sometimes prescribe vitamin B complex for patients to help relieve stress; Some doctors also think that patients should do more aerobic exercise and let the body's natural regulation mechanism adjust itself through exercise. In Hong Kong, many students and teachers have local psoriasis, mainly in the palms, arms, legs or shoulders. An American pharmaceutical company recently invented an injection which can control the course of severe patients and make their skin smooth again. This injection was also introduced to Canada for clinical trials in 2006. But this kind of injection can't cure psoriasis. Once the injection is stopped, the problem will appear again.