Psoriasis, commonly known as psoriasis, is a chronic inflammatory skin disease with a long course and a tendency to relapse. The disease mainly occurs in young adults, with clinical manifestations of erythema and scales, which can occur all over the body, especially in scalp and limbs, and is more common in winter.

Eczema mostly occurs within 2 years old, while psoriasis can occur within 10 years old, but mostly after 15 years old. It is generally believed that there are two peak ages: 16 ~ 30 years old and 50 ~ 62 years old.

Unlike eczema, which is very prominent in itching, psoriasis generally has no itching, or even if it has itching, it is not as serious as eczema. Psoriasis generally involves: scalp, elbow and knee; Secondly, nails, hands, feet, trunk and gluteal groove are all involved. Generally, it is a red macula, and a few have aseptic pustules.

Psoriasis can be divided into different types according to the characteristics of rash. There are chronic plaque type, drip type, red skin type, pustule type and so on. Psoriatic arthritis coexists when joints are involved. Among them, chronic plaque type is the most common, and more than 80%-90% are chronic plaque type.