1.Psoriasis vulgaris is the most common type, mostly with acute onset. The typical manifestation is erythema with clear boundaries and varying shapes and sizes, surrounded by an inflammatory redness. Slightly infiltrated thickening. The surface is covered with multiple layers of silvery white scales. The scales are easy to scrape off, and after scraping the translucent film is light red, and small bleeding spots (Auspitz sign) can be seen after scraping the film. The lesions are usually found on the head, sacral region and extensor surfaces of the limbs. Some patients feel varying degrees of itching. 2. Pustular psoriasis is less common and is divided into generalized and palmoplantar types. Generalized pustular psoriasis is the appearance of clusters of superficial sterile pustules on erythematous plaques, some of which may fuse to form pus lakes. It can develop all over the body. It is more common in the flexural and folds of the extremities, and the oral mucosa may be involved at the same time. Acute onset or sudden exacerbation is often accompanied by systemic symptoms such as chills, fever, joint pain, general malaise, and increased white blood cell count. Most of the episodes are cyclic and often appear as common psoriatic lesions during remission. Palmoplantar pustular lesions are confined to the hands and feet, occur symmetrically, are in good general condition, are stubborn and recurrent 3. Erythrodermic psoriasis, also known as psoriatic exfoliative dermatitis, is a severe form of psoriasis. It is often caused by the external use of strong stimulating drugs, long-term application of large amounts of glucocorticoids, too rapid reduction or sudden discontinuation of drugs. It manifests as diffuse flushing, swelling and flaking of the skin all over the body, accompanied by systemic symptoms such as fever, chill and discomfort, enlarged superficial lymph nodes and increased white blood cell count. 4.Arthritic psoriasis, also known as psoriatic arthritis. Patients with psoriasis also have rheumatoid arthritis-like joint damage, which can involve large and small joints all over the body, but the interphalangeal joint lesions are the most characteristic. The affected joints are red, swollen and painful, and the skin around the joints is often red and swollen. Joint symptoms often worsen or decrease simultaneously with skin symptoms. Blood rheumatoid factor is negative.