The prevalence of psoriasis in the natural population is about 2%. The cause of psoriasis is not known, but it is a polygenic genetic disease in which genetic factors interact with environmental factors and other factors. At present, there are many drugs for psoriasis. 1, topical drug treatment 1. 1 glucocorticoids Glucocorticoids are most widely used in the treatment and have obvious efficacy, commonly used 0. 1% Haxenaid liquid, flumethasone ointment, etc., but long-term use can cause side effects such as skin atrophy, capillary dilation, folliculitis, pigmentation or hypopigmentation. Large long-term application of strong glucocorticoid preparations can cause systemic reactions, and even induce pustular or erythrodermic psoriasis after stopping the drug. The dermatological venereal disease department of Beijing Military General Hospital, Peng Shaowen 1. 2 Vitamin A acid cream Vitamin A acid cream is one of the most commonly used and effective topical drugs in the past decade, vitamin A acid has the role of regulating epidermal cell differentiation and proliferation, can improve the abnormal differentiation of keratinocytes, inhibit the excessive proliferation of keratinocytes, anti-inflammatory effect, commonly used concentration of 0. 025% ~ 0. 1%. 0. 05% ~ 0. 1% tazarotene gel is a new generation of preparations, can be combined with super potent glucocorticoid preparations or ultraviolet light. Corticosteroid preparations or ultraviolet light combined application, note that high concentrations can cause acute or subacute dermatitis and erythema pruritica and other side effects. Vitamin D3 derivatives are one of the most commonly used and effective topical medications in the past two years, and were developed in 1980 for the treatment of psoriasis. Vitamin D3 is continuously hydroxylated by the liver and kidneys to form the active metabolite osteotriol 21α, 252 dihydroxyvitamin D3, which plays an important role in maintaining calcium and phosphorus metabolism and bone mineralization in the body, and osteotriol also regulates epidermal growth, keratinization and inhibits inflammation, inhibits keratinocyte proliferation and promotes their differentiation. Vitamin D3 derivatives include carbotriol and tacalcitol, etc. Carbotriol was first used in clinical practice; osteotriol ointment is mainly composed of 1α, 252 dihydroxyvitamin D3, which acts by binding to receptors in the cytoplasm of keratinocytes to promote the proliferation and differentiation of keratinocytes back to normal. Ji Suzhen et al. found that osteochondriol ointment was safe and effective in the treatment of plaque psoriasis. Foreign trials have shown that the safety of 3μg/g osteopontin ointment is better than 50μg/g carbotriol ointment in the treatment of plaque psoriasis, and it has no significant effect on calcium and phosphorus metabolism. 1. 4 Pyrithione zinc aerosol The main component is pyrithione zinc, which can promote epidermal cell proliferation, keratin formation, keratin separation and anti-hyperkeratosis, inhibit the growth of epidermal fungi and bacteria such as Malassezia furfur, regulate sebum secretion, and relieve pruritus associated with scaly skin disease. Pyrithione zinc aerosol is commonly used abroad for the treatment of psoriasis and seborrheic dermatitis, and its efficacy has been confirmed by years of clinical application. In China, Luo Shaomiao et al. reported that the efficacy of pyrithione zinc aerosol in the treatment of psoriasis vulgaris was precise and rapid. Han Ling et al. reported that the safety of pyrithione zinc aerosol in the treatment of psoriasis vulgaris was good. 2. Systemic therapeutic drugs 2. 1 Methotrexate (MTX) MTX is still one of the most effective drugs for the treatment of psoriasis and is effective in severe psoriasis. The drug mainly inhibits the T cell-mediated immune response and acts on the proliferating activated lymphocytes in the body to inhibit the proliferation of keratinocytes, and is taken orally three times a week, or injected intravenously, intravenously or intramuscularly once a week, and the dosage is less than 15 mg as a safe dose. MTX can be used to treat patients with moderate to severe psoriasis for more than 6 weeks, and generally the skin lesions improve significantly after 2 weeks of treatment, and the rash completely disappears within 1 month in more than 90% of cases, and most cases can be clinically cured after 4 weeks. The main side effects of this drug are anorexia, hematopoietic system and liver dysfunction, so the dosage and usage should be strictly controlled. Contraindications include hepatic and renal insufficiency, abnormal hematopoietic function, pregnancy, and active ulcers. Relevant laboratory tests should be performed before and during the drug administration. Routine blood and liver function should be checked once every one to two months and kidney function once every four to six months. Folic acid can supplement the decrease of serum folate level caused by the increase of cell division and metabolism in psoriasis patients, and the adverse effects of MTX can be reduced by taking small doses of folic acid. 2. 2 Retinoic acid Retinoic acid: Avelic acid is the safest one among the three first-line drugs (MTX, Avelic acid and cyclocytin A) approved by the United States for the treatment of psoriasis, and it is especially suitable for patients who need to take the drug for a long time. It is one of the more effective drugs for the treatment of psoriasis. The initial dose of 10-20 mg/d is given orally, and the dose is gradually increased until satisfactory efficacy is achieved and then reduced for maintenance. Sun Jianfang et al[ 12 ] applied Avia to treat 120 cases of psoriasis vulgaris, with an efficiency of 72. 7%, but 94. 41% of patients experienced various drug-related adverse reactions during treatment, mainly lipitis, skin flaking, dry skin, and pruritus, which were mostly mild or moderate and tolerated by patients. 3. 48%-15. 65% of patients had increased liver function and blood lipids. Most of them returned to normal after 2 weeks of discontinuation. Compared with MTX, Avelox has faster onset of action and better overall efficiency than MTX, but the side effects such as dry skin and itching are large; MTX has slower onset of action and less side effects, which is easily accepted by patients. 2. 3 Cyclosporine Cyclosporine is a potent immunosuppressant, mainly acting on proliferating pathogenic T cells in psoriasis lesions, and is effective in all types of psoriasis. The initial dose is 2.5 ng?kg- 1 ?d- 1, divided into two oral doses. After 4 weeks, the dose can be increased by 0.5-1 mg/kg per month, generally not exceeding 5 ng?kg- 1 ?d- 1, and then decreased. Adverse effects are obvious nephrotoxicity (interstitial fibrosis and tubular atrophy), elevated blood pressure, abnormal renal function, long-term use may produce hypomagnesemia, hyperkalemia, elevated blood lipids, and may cause malignant tumors and lymphoproliferative diseases. Aminoglycosides, amphotericin B, and methotrexate can increase their nephrotoxicity. Because of the large side effects, cyclosporine A is often used in severe psoriasis where conventional treatment is ineffective, and the course of treatment should be less than one year. It is often used in combination with Avastin or MTX, and the dosage is reduced to stop after the symptoms are relieved. It has immunosuppressive and anti-inflammatory effects. It is most effective for psoriasis in the progressive stage of common acute drip psoriasis or psoriasis with the tendency to develop into erythrodermic disease, and is also effective for pustular, arthritic and erythrodermic psoriasis. The side effects are anti-fertility, toxicity to germ cells, hemorrhage and necrosis of liver and heart, decrease of white blood cells, and toxic effects to central nervous system. 2. 5 Compound glycyrrhizin is a saponin compound, which has anti-inflammatory, anti-allergic and immunomodulatory effects, and also has inhibitory effects on human complement, and there are no obvious side effects. The author applied compound glycyrrhizin tablets for the treatment of psoriasis, taking 50 mg/d orally, 3 times/d, or intravenous injection of compound glycyrrhizin 100 ml/d for 3 weeks. It can effectively relieve the symptoms and improve the quality of life, with definite efficacy. 3, physical therapy ultraviolet therapy is an important method for the treatment of skin diseases, the traditional ultraviolet radiation treatment methods are psoralen plus long-wave ultraviolet therapy and broad-spectrum medium-wave ultraviolet therapy. Narrow-spectrum medium-wave ultraviolet wavelength, compared with broad-spectrum medium-wave ultraviolet penetration, can reach the dermal papilla layer. Narrow-spectrum medium-wave UV irradiation therapy is a kind of light therapy gradually developed in recent years, and its efficacy on some skin diseases such as psoriasis is better than broad-spectrum medium-wave UV, and the phototoxic reaction and systemic adverse reaction are less than long-wave UV therapy. It has been suggested that the efficacy of narrow-spectrum medium-wave UV treatment for psoriasis is related to the apoptosis of T lymphocytes and Langerhans cells and the inhibition of the release and transport of proinflammatory factors. He Hongxia et al. applied narrow-spectrum medium-wave ultraviolet radiation to treat psoriasis vulgaris with an efficiency of 91.7% and a good safety profile. Narrow-spectrum medium-wave ultraviolet irradiation therapy is increasingly used in dermatology, and its efficacy is remarkable and convenient, without the need for photosensitizers, with low systemic adverse effects and mild phototoxic reactions. However, there are still many problems in clinical practice, such as inconsistent treatment protocols, long-term adverse effects still need long-term observation, and the mechanism of action is not yet completely clear, so the research on narrow-spectrum medium-wave ultraviolet radiation needs further improvement. 4.Chinese medicine therapy Clinical practice has confirmed that Chinese medicine is effective in treating psoriasis. Chinese medicine believes that “heat in the blood” is the main cause of psoriasis. In recent years, the research of some scholars has also proved the effect of Chinese medicine in treating psoriasis with less adverse reactions. Hou Suchun et al. applied the compound formula of cooling the blood and activating the blood (15 g of Da Qing Ye, 30 g of Sheng Di, 12 g of Baicalin, 9 g of Comfrey, 12 g of Danshen, 6 g of Red Peony, 9 g of Dampi, 12 g of Angelica, 30 g of Fu Ling, 9 g of White Moss Peel, 6 g of Thornbush, 20 g of Honeysuckle) to treat 133 cases of psoriasis, taking one dose daily for 4-8 weeks, with the following results: the efficiency reached 72.18% and no adverse effects were observed. Wu Shengli et al. treated 50 cases of common psoriasis with detoxification and siltation soup (30 g of raw earth, 6 g of red peony, 9 g of dandan bark, 30 g of panax quinquefolium, 9 g of samphire, 30 g of sarsaparilla, 30 g of shuyangquan, 30 g of zeqi, 30 g of fu ling, 15 g of bitter ginseng and 30 g of danshen), taking 1 dose daily for 4 weeks, and the effective rate reached 90%. The experiments with mice showed that Detoxification and Desiccation Soup could significantly increase the granular layer of the epidermis of the tail scales of mice, thus it was assumed that Detoxification and Desiccation Soup could play a therapeutic role by inhibiting the proliferation of epidermal cells and transforming incomplete keratinized cells into fully keratinized ones. Sun Li-Yun et al [ 18 ] investigated the mechanism of the treatment of psoriasis with cool blood and blood activating capsules (Panax quinquefolium, Baimao root, Antelope powder, Xi Cao, Zi Cao and Sheng Di) and found that the capsules could induce apoptosis of cultured keratinocytes, thus achieving the purpose of treating psoriasis. 5.Immunobiological treatment In the treatment of psoriasis, most of the biological immune agents have been used clinically, and their efficacy is more certain. So far, more than 3,500 patients with psoriasis have undergone clinical trials with CD11a monoclonal antibodies, and statistics show that CD11a monoclonal antibodies are an effective and well-tolerated agent for the treatment of moderate-to-severe chronic plaque psoriasis, with no additional adverse effects over 3.3 years of use. The results showed that patients treated with different doses of adalimumab showed better lesion improvement and quality of life than the placebo group. Tumor necrosis factor inhibitor: Tumor necrosis factor is produced by activated T cells, which can promote fibroblast proliferation, produce interferon and collagenase, accelerate osteolysis of osteoclasts and inhibit osteogenesis. heiberg et al. reported that the clinical symptoms of arthritic psoriasis treated with anti-tumor necrosis factor alone were significantly better than those of methotrexate alone. 6.Conclusion Psoriasis is a chronic disease that is difficult to treat and prone to recurrence, and scholars at home and abroad are constantly searching for more effective drugs, and drugs for psoriasis are emerging. The author believes that the treatment of psoriasis needs to adopt comprehensive treatment, according to the patient’s compliance, to achieve individualized drug treatment as far as possible, to improve the safety and effectiveness of drugs and to reduce the occurrence of adverse drug reactions, so as to achieve the best therapeutic effect.