Topical medications are the basic treatment for psoriasis. Topical medications can not only control the inflammatory response of local lesions, but also reduce the dose of systemic medications, thus reducing the adverse effects of systemic medications. The following is a brief introduction of some topical drugs commonly used to treat psoriasis according to the type of drugs. 1.Keratin promoter and keratin relaxer Keratin promoter can promote normal epidermal keratinization and normalize the stratum corneum, commonly used drugs are 3% salicylic acid and 5% ichthyolipid. Keratolytic agents can promote the normal keratinocyte loosening and shedding, commonly used drugs include 5%-10% salicylic acid, 10% rezosin, 10%-30% ichthyolipid, etc. These drugs are suitable for plaque type psoriasis when the scales are thicker. 2.Glucocorticoids Topical glucocorticoids have anti-inflammatory, immunosuppressive, vasoconstrictive and anti-proliferative effects. According to their anti-inflammatory strength, they are divided into low-potency, medium-potency, strong-potency and super-potency drugs. The common low potency drugs are hydrocortisone acetate and methylprednisolone; the medium potency drugs are hydrocortisone butyrate, dexamethasone, tretinoin, flumethasone pivalate, and mometasone furoate; the strong potency drugs are dermatologic acid, betamethasone valerate, and harcionide; and the extra potency drugs are clobetasol propionate, halometasone, difluprednisone, and fluticasone propionate. The choice of use should be based on the type of lesion, site of onset and age of the patient to ensure efficacy while minimizing adverse effects. Weak hormones are preferred for the face and inter-rub areas (axillae, inframammary, groin and perineum, etc.), medium or strong hormones for the skin of the trunk and extremities, and ultra-potent hormones for the palms of the hands and the feet and plantars. Because of the possibility of systemic absorption, weak to moderately potent glucocorticoids are preferred for large areas. Topical glucocorticosteroids are fast-acting in the treatment of psoriasis, but sudden discontinuation will lead to rebound, so step therapy (gradually reduce the intensity of hormones and maintain treatment with medium- and low-acting hormones), intermittent shock therapy (after 2-3 weeks of topical super-/strong-acting hormones, the lesions will subside by at least 85%, after which topical super-/strong-acting hormones will be used only 3 times at the weekend) and combination therapy (combined with hormone-free drugs) can be adopted. 3. Retinoids (retinoids) Retinoids can mediate the abnormal proliferation and differentiation of keratin-forming cells, regulate skin immune abnormalities and control dermal inflammation. There are more topical retinoic acid preparations, and the one recognized as effective so far is tazarotene, also known as ethinyl retinoic acid, which is a third-generation retinoic acid drug, first marketed in Germany in 1996 and now used in several countries for the treatment of adult plaque psoriasis and psoriatic nail damage. The drug is applied topically once a day and is recommended for nighttime application as its stability decreases after exposure to light. It works in most patients 1 week after application and the duration of treatment is 6-12 weeks. The drug should not be used externally on more than 20% of the body surface area and should be avoided in the axillae, groin and other inter-rubbing areas. It is prohibited for pregnant women, lactating women and women with recent childbirth desire. 4.Vitamin D3 derivatives Active vitamin D3 can bind with vitamin D3 receptors in the body to inhibit keratinocyte proliferation, promote normal cell differentiation, regulate local immunity, etc., control local inflammation and normalize cell differentiation. At present, there are Darex Ointment, Darex Application and Mengfu Ointment available in China, which are used for the trunk and limbs, scalp and face of common psoriasis respectively. However, the upper limit of drug dosage needs to be noted when using them, and the level of blood calcium and urine calcium may be affected if the drug is overdosed. 5.Tar category includes coal tar, black bean distillate and bran distillate. The disadvantage of these drugs is black, easy to contaminate clothing, the advantage is that there are lotion formulations, can be used for bathing. 6.Calcium-adjusted neurase inhibitor Tacrolimus ointment (trade name Putnam) can be used for facial and inter-rubbing parts of the skin lesions. 7.Other Some Chinese herbal ointments have the effect of stopping itching and relieving inflammation of psoriasis lesions, and you can also choose Chinese herbal decoction for medicinal bath, which helps to shed scales and stop itching. In short, there are many topical drugs for psoriasis, and patients can go to the dermatology department of a regular hospital to find a professional doctor to choose according to each person’s situation. The following principles need to be kept in mind when using them: mild emollients are appropriate in the acute phase, and while applying systemic emollients in the stable and receding phases, drugs with stronger effects can be applied topically to the lesions, but they should start at low concentrations, usually one to two times a day. Tazarotene, medium- and strong-acting glucocorticoids, and carbotriol can be used as first-line agents for topical treatment. Commonly used combination regimens include glucocorticoids combined with tazarotene or carbofurantrin, which can achieve fast onset of action and low adverse effects. However, the two drugs should not be mixed and used directly, as this will halve the drug concentration and reduce the efficacy, and the correct application method is topical glucocorticoids in the morning and topical tazarotene or carbofurantrin at night. There are also compounded preparations, such as calcipotriol betamethasone ointment, which can be applied topically once a day and is more convenient.