Physical examination, pathologic examination and dermoscopy are needed to suspect psoriasis. 1. Physical examination: For patients who are suspected of having psoriasis, the doctor will conduct a physical examination based on the shape, color, texture and distribution of the skin lesions as a preliminary judgment. 2. Pathological examination: For patients who are suspected of having psoriasis, doctors will also cut part of the skin lesions for pathological examination if necessary, which is of great diagnostic value for confirming the diagnosis of psoriasis. 3. Dermoscopy: patients can also undergo dermoscopy to observe the surface of the skin lesions and subcutaneous structural characteristics, which can assist in the diagnosis of psoriasis. For patients who are suspected of having psoriasis, it is recommended to go to the hospital and under the guidance of the doctor to carry out relevant examinations.