Erythematous scaly skin diseases including psoriasis, psoriasis, pityriasis rosea, acute acne-like lichenoid furfura, chronic lichenoid furfura, lichen planus, etc., which belongs to a large class of diseases, clinical manifestations of erythema, maculopapular, plaques, as well as silver-white scales adhering to the surface of the skin, daily life and the people of the closest relationship with psoriasis and pityriasis rosea, the two based on the clinical manifestations and not easy to distinguish, the same are manifested in red spots, maculopapular, plaque and scaly skin. The same are manifested as erythema, maculopapular rash and scales, the specific differentiation methods are as follows: 1, the occurrence of parts and performance: psoriasis rash occurs in the head and face, trunk and limb extensor, manifested as erythema, maculopapular rash, the surface of the skin is silvery-white scales, if the surface of the scales are scraped off, the film will be seen to see the dark red, if you then scrape down, you will see the point of hemorrhage; furfury rash occurs in the trunk and proximal limbs, the rash is silver-white scales attached to the skin surface, and the skin surface is silver-white. The proximal part of the limbs, the rash is oval, the scale on the surface of the skin is free edge inward, the scale is very thin, if you scrape it off, there will not be a positive film sign, and there will not be a bleeding spot; 2, the course of the disease: psoriasis is a chronic, inflammatory, autoimmune-related, genetically related skin disease; pityriasis rosea is self-limiting to a certain extent, and the approximate course of the disease is about 1-2 months can be recovered; 3, the treatment: psoriasis is a Chronic course of the disease, need long-term treatment; pityriasis rosea generally 1-2 months can be recovered. There are common points in the treatment of the two, such as both preferred phototherapy, phototherapy that is, refers to the illumination of narrow-wave ultraviolet light, can be conducive to the recovery of skin lesions.