Vulvar Psoriasis

　　1. Causes of onset

　　The etiology of the disease is not yet fully clear. Recently, most scholars believe that the disease is related to the following factors:

　　1. Genetic factors

　　The disease has a family history and a genetic predisposition, with a reported range of 10% to 80% abroad, and generally 10% to 23.8% in China. It is an autosomal dominant inheritance with incomplete penetrance, and can also be an autosomal recessive inheritance. However, there is no definite conclusion on the mode of inheritance in China. The frequency of HLA-B13 and B17 in patients with psoriasis abroad is significantly increased, but there is also an increase in the frequency of HIA-B3, C77, W6. The frequency of HLA-B13 and HLA-B17 in patients with psoriasis in China is also rising, and there is also an increase in HLA-A1, a significant decrease in the frequency of HLA-B40 and W35, but the frequency of HLA has no significant meaning for evaluating the clinical and prognosis of individual patients.

　　2. Infection factors

　　Including viral infection and bacterial infection, among which streptococcal infection is closely related to the onset of psoriasis, especially some patients with acute pustular, arthropathy, and erythroderma often have symptoms such as upper respiratory tract infection or tonsillitis, and the level of anti-O is often elevated. It is generally considered to be an allergic reaction caused by bacterial toxins.

　　3. Drug factors

　　Now it has been found that the following drugs can cause psoriasis, such as: beta-blockers, lithium, antimalarial drugs, etc. Recently, it has been found that terbinafine, calcium channel blockers (nicardipine, nifedipine, nisoldipine, verapamil, diltiazem), captopril, glibenclamide, and lipid-lowering drugs gemfibrozil, dexamethasone, and certain cytokines such as G-CSF, interleukin, INF-α, INF-β can also trigger psoriasis.

　　4. Immune factors

　　The cell-mediated immune function of patients is decreased, and there are defects in the circulating T cells. C3 complement and/or immunoglobulin deposits can be found in the blood vessel wall and/or dermo-epidermal junction of the skin lesions. Ant IgG antibodies exist in the serum, and anti-keratin layer autoantibodies are detected by immunofluorescence.

　　In addition, it is also related to metabolic disorders, endocrine disorders, mental factors, food and other factors; seasonal changes, trauma, or surgery can trigger the disease.

　　2. Pathogenesis

　　1. Pathogenesis

　　The pathogenesis of psoriasis has not been fully understood, with many theories. Psoriasis has three main characteristics: abnormal differentiation, overgrowth of keratinocytes, and inflammation. Basal keratinocytes enter the proliferative pool significantly more than normal, with accelerated cell proliferation and mitotic cycle shortened from the normal 311h to 37.5h. The time for epidermal passage is shortened from 26 to 56 days to 3 to 4 days. The number of proliferating mononuclear cells in the peripheral blood of patients with psoriasis is significantly increased. T and B cells are activated before entering the skin lesions. Local macrophages also activate and proliferate T cells locally in the skin.

　　In addition, keratinocytes (KC) can synthesize and secrete various cytokines under the stimulation of certain physical, chemical, and biological environmental factors, and activate T cells in a non-antigen-dependent manner. KC can express MHC-2 class antigens such as HLA-DR and B7 molecules, and under certain conditions, KC has the ability of antigen-presenting cells (APC), providing co-stimulatory signals for T cell activation, which is an important intrinsic mechanism for local T cell activation. KC as an APC may mainly be significant for maintaining psoriasis lesions. Polyclonal or oligoclonal T cell activation plays a role in the initiation and maintenance of psoriasis. Abnormalities of psoriasis epidermal cells are highly dependent on CD4 T cells, and more importantly, CD8 T cells are necessary to maintain the clinical and pathological changes of psoriasis.

　　Abnormal signal transduction of T cell activation in psoriasis is also related to the disease. Superantigens and autoantigens are more related to the disease process of psoriasis, and these antigens may play a complementary role in modifying the expression of the disease in T cells. The changes in the superficial dermal blood vessels of psoriasis lesions are also one of the characteristics of the disease. It includes excessive tortuosity and dilatation of the venous branches of the dermal papillary capillary plexus, increased permeability, proliferation of endothelial cells, and the formation of new blood vessels. The newly formed dermal capillaries persist in the psoriasis lesions and the surrounding skin that appears normal. Highly expressed VEGF, bFGF, PDECGF/TP, and other angiogenic factors in psoriasis lesions play a certain role in the pathophysiology of psoriasis. Cytokines such as TgaseK and IGF, 1R, interleukin-1, interleukin-8, GRO-α, TSP-1, TNF-α, KGF, TGF-α, ICAM-1, and other cytokines produced by epidermal cells are related to psoriasis. Arachidonic acid and its derivatives are also related to psoriasis, but they are not the main factors.

　　2. Histopathology

　　The basic histological characteristics of psoriasis vulgaris lesions include thickening of the epidermal keratin layer, incomplete keratinization, and reduction or disappearance of the granular layer; thickening of the epidermal prickle layer, downward extension of the epidermal papillae呈club-shaped, with a small number of neutrophils aggregated in the non-keratinized area to form Munro microabscesses; thinning of the prickle layer above the dermal papillae; dilatation and tortuosity of the capillaries in the upper dermis, reaching the top; infiltration of mononuclear cells around the blood vessels in the superficial dermis. The histological changes of erythrodermic psoriasis, in addition to the basic characteristics of psoriasis, may also show changes of chronic dermatitis and eczema. The histological characteristics of pustular psoriasis are roughly similar to those of psoriasis vulgaris. However, intercellular edema of the epidermal prickle cells is more obvious, and there are spongy pustules (Kogoj) in the upper epidermis, filled with neutrophils.

　　Psoriasis, commonly known as lichen planus, is a chronic erythematous and scaly skin disease with characteristic skin lesions. It has a long course, is prone to recurrence, and a few patients may not recur after cure. Patients have varying degrees of vulvar itching, burning sensation, or extreme discomfort. Initially, inflammatory flat papules of different sizes like needle caps appear on the mons pubis, labia minora, and other places, which gradually grow into pale red, punctate, coin-shaped, map-like, annular papulovesicular eruptions. Generalized cases may have symptoms such as fever and general malaise.

　　Patients have varying degrees of vulvar itching, burning sensation, or extreme discomfort. Initially, there are inflammatory flat papules of different sizes like needle caps on the mons pubis, labia minora, and other places, which gradually grow into pale red, punctate, coin-shaped, map-like, annular papulovesicular eruptions. The surface of the papules is covered with multiple layers of silver-white scales, with a slight red halo around them. After gently removing the epidermal scales, a semi-transparent film is exposed at the base (film phenomenon). The characteristic of scraping off this film is the appearance of small bleeding points. The vulva is prone to sweating, moisture, and easy to rub, and the rash often gets rubbed off and develops eczematous changes. The eczematous changes in the vulvar folds are more obvious, and the lesions in the mons pubis are similar to seborrheic dermatitis.

　　According to the clinical characteristics of psoriasis, it can generally be divided into common type, pustular type, articular type, and erythroderma type, etc. The types related to the vulva have the following manifestations:

　　Common psoriasis

　　It is the most common type, usually presenting with an acute onset. Initially, it appears as red inflammatory papules, ranging from millet to mung bean size, which gradually expand and merge into red plaques with clear borders. There is a red halo of 0.2 to 0.5 cm around them, with infiltrated base and a surface covered with multiple layers of dry, silver-white scales. The scales are less in acute lesions and more in chronic lesions. The scales in the central part of the skin lesions are more firmly attached, and the scales do not exceed the edge of the erythema, which is more characteristic. After scraping off the scales, a thin, translucent, and slightly pink film appears, known as the film phenomenon. After scraping off the film, the top of the dermal papillary layer is reached, the capillaries are scraped, and small出血 points appear like dewdrops, known as the Auspitz sign. The skin lesions have reduced sweating, and the reduced sweating after the skin lesions subside can last for a period of time without immediate recovery. The distribution characteristics of the skin lesions are punctate, which is a feature of punctate psoriasis, common in children, especially after infections such as tonsillitis. It is closely related to infection. If the skin lesions are large, they can be circular and merge into a map-like pattern. When the skin lesions are in the regression phase, they can be annular or arranged in a strip-like pattern. The number of skin lesions can range from 1 to more than 100, distributed symmetrically, occurring all over the body, with a wide distribution. Generally, it is more common on the scalp, extensor surfaces of the limbs, and buttocks, but a few patients have localized skin lesions in places such as the scalp, vulva, inguinal folds, and other skin folds.

　　Furrow psoriasis accounts for 3% to 5% of the disease, mainly affecting the inguinal area, axilla, breast perineum, and other furrowed parts. The border of skin lesions is clear, erythema is generalized, without scales. The local area of the furrow is moist and prone to friction, and the surface of the skin lesions is moist and shows an eczematous change. Psoriasis in mucosal areas is relatively rare, usually seen in the glans penis and inner prepuce of males, as clear marginal infiltrative red or dark red spots or plaques. The scales are dry and smooth, with few or no scales, which can exist for a long time, or be located in the bladder, urethra, etc. This disease rarely occurs in the mucosa of the female genitals, and occasionally occurs as white or grayish-yellow slightly elevated spots or plaques, with slight infiltration at the base and a little redness around. The rash surface has no scales. Vulvar psoriasis often coexists with psoriasis lesions in other parts of the body, and is rarely solitary.

　　This disease is divided into active period, stable period, and regression period.

　　1. Active period: New rashes continually appear, old lesions continue to expand, scales thicken, inflammation is obvious, with inflammatory erythema around, and there is a similar reaction at this time.

　　2. Stable period: The condition remains in a stationary stage, with no new rashes appearing, and old rashes do not subside.

　　3. Regression period: Inflammatory infiltration gradually subsides, scales decrease, redness fades, and even skin lesions disappear, leaving hypopigmented or hyperpigmented spots.

　　2. Erythroderma type psoriasis

　　It is more common in adults, induced by topical irritant drugs or the regression of pustular psoriasis. Sudden withdrawal of a large amount of hormone can also trigger it. The clinical manifestations include generalized red or dark red skin on the whole body, with obvious inflammatory infiltration, a large amount of dandruff-like scales on the surface, continuous desquamation. For patients with erythroderma type, there is widespread skin infiltration and swelling, and swelling in the perineum, inguinal area, anus, etc. is also more obvious, with a large amount of exudation, forming serous crusts. There is a lot of secretion under the crusts, and skin cracks often occur during activity. Mucosal symptoms are also prominent, and the mucosa of the female genitals, urethra, and anus is often eroded with secretion. The pain during urination is severe, and it is easy to develop perineal infection.

　　3. Pustular psoriasis

　　Based on the existing skin lesions, it manifests as acute erythema, with dense sterile pustules ranging from pinpoint to mung bean size on the surface. It can be generalized throughout the body or localized to the palm and sole of the foot, with a chronic course, recurrent attacks. Similar skin lesions appear in the vulva, and vesicle walls break due to easy friction, leading to erosion, scab formation, purulent scabs, and exudation.

　　To make patients understand the basic knowledge of the disease, pay attention to eliminate mental trauma, relieve mental concerns, and try to avoid various triggering factors such as physical and chemical stimuli, avoid smoking and drinking, limit the intake of spicy and stimulating foods, strengthen physical exercise, pursue可疑 causes, pay attention to avoid upper respiratory tract infection and clear infectious foci, and also be cautious in medication, avoid using strong irritant external drugs and ultraviolet irradiation during the acute stage.

　　1. Vaginal secretion examination, blood routine

　　2. Blood routine, secretion examination. Tissue pathological examination.

　　One, therapeutic diet for vulvar psoriasis

　　1. Sophora japonica flower porridge: Method: Put 30 grams of Sophora japonica flower and 30 grams of turmeric into a pot, add an appropriate amount of water, and boil for half an hour. Remove the residue and add 60 grams of glutinous rice to cook into porridge. Add an appropriate amount of red sugar and mix well. Eat once a day, 10 days as one course. This porridge has the effect of clearing heat and cooling blood, dispelling wind and itching.

　　2. Plantago asiatica Coix Seed Porridge: Put 15 grams of plantago asiatica and 9 grams of silkworm chaff into separate cotton bags, tie the bags, and put them into a pot. Add an appropriate amount of water, and boil for half an hour. Remove the bags, add 30 grams of coix seed to the juice, and cook into porridge. Add an appropriate amount of sugar and mix well. Eat once a day, 10 days as one course. This porridge has the effect of clearing heat and detoxifying, and dispelling wind and dampness.

　　3. Cassia twig Coix Seed Porridge: Put 9 grams of cassia twig and cow knee, 18 grams of duzhong, into a pot, add an appropriate amount of water, and boil for half an hour. Remove the residue and add 30 grams of coix seed to cook into porridge. Add an appropriate amount of sugar and mix well. Eat once a day, 10 days as one course. This porridge can clear heat and detoxify, activate blood circulation, and relieve wind and dampness.

　　4. Portulaca oleracea Porridge: Put 50 grams of glutinous rice and 60 grams of chopped fresh Portulaca oleracea into a pot, add an appropriate amount of water, and cook until the rice is almost done. Add an appropriate amount of red sugar and cook into porridge. Eat when cooled to a warm temperature. Eat 1-2 times a day, 7-10 days as one course. It has the effect of cooling blood and dispelling wind.

　　5. Prune Paste (Traditional Chinese Medicine Recipe) for the treatment of psoriasis. Ingredients: 2.5 kilograms of plums. Method: Wash and pit the plums, boil with water, concentrate into a 500 milliliter paste, pour into bottles for storage. Take 10 grams three times a day, dissolved in warm water.

　　6. Betel Nut Ginger Soup (Traditional Chinese Medicine Recipe) for the treatment of psoriasis. Ingredients: 1 betel nut, 10 grams of ginger juice, 50 milliliters of honey, 100 grams of glutinous rice. Method: Grind the betel nut into powder, boil for 15 minutes, cool and precipitate to take the juice, cook the glutinous rice into porridge, add ginger juice, betel nut juice, and honey, and boil again. Eat on an empty stomach.

　　7. Angelica Sinensis羊肉汤: Take 15 grams of Dodder seed and wrap it in a cheesecloth bag, tie it tightly, and put it in a pot with 9 grams of Angelica Sinensis and 18 grams of Cynanchum wilfordii. Boil the water for half an hour, remove the residue, add 60 grams of chopped mutton to the juice, and cook into soup. Add appropriate seasonings and it can be eaten. Eat once a day, 7-10 days as one course, with the effect of dispelling wind and drying dampness.

　　Two, what foods are good for the body when eating for vulvar psoriasis

　　1. Eat more foods rich in protein and carbohydrates. Examples include milk, soy milk, eggs, and meats.

　　2. Drink plenty of water and eat fresh fruits and vegetables. Examples include apples, pears, bananas, strawberries, kiwis, cabbage, green vegetables, rapeseed, mushrooms, seaweed, and kelp, etc.

　　3. It is advisable to eat foods that cool blood and detoxify. Examples include mung beans, glutinous rice, cucumbers, bitter melon, portulaca oleracea, green tea, etc.

　　Three, it is best not to eat certain foods for vulvar psoriasis.

　　1. Avoid eating foods that can cause allergic reactions, such as fish, shrimp, crabs, etc.

　　2. Eat less spicy and irritating foods. For example: onions, black pepper, chili, Sichuan pepper, mustard, fennel.

　　3. Avoid eating fried and greasy foods. For example: fried dough sticks, butter, butter, chocolate, etc., which have the effect of promoting dampness and increasing heat, which can increase the secretion of leukorrhea and is not conducive to the treatment of the disease.

　　4. Quit smoking and drinking. Smoking and drinking are highly irritating and can exacerbate inflammation.

　　One. Precautions before treating vulvar psoriasis

　　Prevention: Patients should understand the basic knowledge of the disease, pay attention to eliminating mental trauma, and relieve mental concerns. Try to avoid various triggering factors such as physical and chemical stimuli. Avoid smoking and drinking, limit the intake of spicy and刺激性 food, strengthen physical exercise, trace suspicious causes, and pay attention to avoid upper respiratory tract infections and clear infectious foci. It is also advisable to use medication with caution, avoid using strong刺激性 external medications and ultraviolet light therapy during the acute stage.

　　Two. Traditional Chinese medicine treatment for vulvar psoriasis

　　Blood-heat type: Equivalent to the active phase, with the treatment principle of clearing heat, cooling blood, and promoting blood circulation. The formula uses: raw Sophora japonica flowers, white mugwort root, raw rehmannia, purple root, red peony root, salvia miltiorrhiza, uncaria tomentosa. Blood-dry type: Equivalent to the stationary phase, with the treatment principle of nourishing blood, moistening the skin, and promoting blood circulation and dispelling wind. The formula uses: uncaria tomentosa, angelica sinensis, asparagus, ophiopogon japonicus, raw rehmannia, turmeric, salvia miltiorrhiza, and honeycomb. The above two formulas are the main ones, and they can be modified according to specific cases. There are also prepared proprietary Chinese medicines such as Compound Qingdai Pill.

　　Three, Western medical treatment for vulvar psoriasis

　　The treatment methods for this disease can only achieve short-term clinical effects most of the time, and it is difficult to cure and prevent recurrence.

　　1. General treatment

　　(1) Immunosuppressant:

　　①Methotrexate (MTX): A derivative of methotrexate and a folic acid antagonist, it acts by competitively inhibiting dihydrofolate reductase, mainly affecting the DNA synthesis phase (i.e., the S phase) of the cell cycle, to prevent the production of DNA and inhibit mitotic division of the nuclear cells, thereby slowing down the rate of epidermal cell division. It is suitable for erythrodermic psoriasis, pustular psoriasis, psoriatic arthritis, and generalized plaque psoriasis, etc., when other treatments are not effective. Dosage: 7.5mg per week, i.e., 2.5mg every 12 hours, taken three times a day, and then administered in the same manner each week. After symptom control, 2.5mg per week is taken to consolidate the efficacy. It can also be taken 2.5mg per time, once a day, for 5 consecutive days, followed by a 2-day rest, then 2.5mg per time, once a day, for another 5 consecutive days, and discontinue for 7 days. There is a single-dose oral form with a weekly dosage of 25-50mg; it is also advisable to start with a smaller dose, initially taking 7.5-25mg orally once a week, and gradually increasing the dose according to the reaction, but not exceeding 0.5mg/kg. Most patients see an effect within 1-2 weeks of taking this drug. Side effects include anorexia, nausea, discomfort, oral mucosal ulcers, leukopenia and thrombocytopenia, and liver function damage. The therapeutic dose and toxic dose of this drug are very close, and it can cause widespread fibrosis and liver cirrhosis. Therefore, caution is needed when using this drug, and the indications should be strictly selected.

　　Contraindications include abnormal liver and kidney function, pregnancy, severe anemia, leukopenia, active gastrointestinal ulcer, and active infection. It is not suitable to use this drug during pregnancy, mental illness, ulcerative colitis, and other diseases.

　　Attention should be paid to the following aspects when using this drug: before taking the medicine, a blood routine should be checked and regular follow-up should be carried out.

　　A, sulfonamide, salicylate, tetracycline, chloramphenicol, aminobenzoic acid, phenytoin sodium, and other drugs should not be taken simultaneously during the period of medication.

　　B, caution should be exercised in patients with low serum protein, as its toxicity may increase.

　　C, when weight loss occurs due to methotrexate (MTX) or other reasons, relative drug overdose may occur, and appropriate dose reduction is required.

　　D, in patients with poor gastrointestinal absorption function, once the function improves, the toxicity may increase due to increased absorption of methotrexate (MTX).

　　E, if renal damage occurs during the course of medication, the dose should be reduced or the medication should be discontinued.

　　F, alcohol should be avoided during the period of taking the medicine.

　　G, contraception should be avoided during treatment, and those who need to be pregnant can consider it after 3 months of discontinuation of the drug, and the dosage should not be too high.

　　H, when used in combination with corticosteroid hormones, the dosage of corticosteroid hormones should not be too high.

　　Hydroxyurea: This drug is suitable for extensive, refractory psoriasis, pustular and erythrodermic psoriasis. Dosage: 0.5g, twice a day, 4 weeks as one course. Or 25-40mg/(kg?d), taken twice, for 4-6 weeks, or 50-80mg/kg, twice a week, for 6-7 weeks. The main side effects are bone marrow suppression, occasional gastrointestinal reactions, central nervous system symptoms, alopecia, fatigue, decreased libido, dizziness, and in some cases, teratogenic effects may occur. The liver and kidney function is rarely affected. Caution should be exercised in patients with severe liver and kidney dysfunction, anemia. Pregnant women should avoid using it. The contraindications of methotrexate (MTX) are also applicable to this drug.

　　Cyclosporin: Mainly affects T lymphocytes, especially during the activation stage, including when they are proliferating and producing lymphokines, it can selectively inhibit the release of interleukin-2 (IL-2) by helper T lymphocytes and block the expression of IL-2 receptors by cytotoxic T cells. It can be used to treat pustular psoriasis, psoriatic arthritis, and generalized plaque psoriasis that does not respond to conventional treatment. Dosage: 3-12mg/(kg?d), taken in divided doses before meals, for several days to several weeks depending on the condition. Oral drops, taken once with milk or beverage after breakfast, initial dose is 4mg/(g?d), after clinical efficacy is achieved, the dose is gradually reduced over 3 weeks, reducing the dose by 0.5mg/(kg?d) every 7-10 days, and when the dose is reduced to 1-2mg/(kg?d), it still needs to be maintained for 6-8 weeks. Dosage: 5-10mg/kg orally per day, maintenance dose 3-5mg/kg. Generally, effects are seen within 3-7 days after taking the medicine, and most cases can be clinically cured within 3-4 weeks. The main adverse reactions include gastrointestinal symptoms, urinary tract irritation, increased blood pressure, fatigue, muscle tremors, etc.

　　④ Tacrolimus: Its mechanism of action is similar to that of cyclosporine, mainly by inhibiting the activity of calcineurin, inhibiting the activation of T lymphocytes, and is effective in systemic treatment of psoriasis. The initial dose is 0.05mg/(kg?d), if there are no adverse reactions, the dose can be increased to 0.1mg/(kg?d) after 3 weeks, and to 0.15mg/(kg?d) after 6 weeks.

　　⑤ Tripterygium glycosides: Effective in the treatment of psoriasis, and also has a good effect on pustular psoriasis. Dosage: 10-20mg per dose, 3 times a day, or Tripterygium tablets can also be used, each containing 33mg of tripterygium alkaloids, 3-4 tablets per dose, 3 times a day; or Tripterygium syrup 15ml per dose, 3 times a day. Gastrointestinal reactions and menstrual disorders are more common as side effects. Taking the medication after meals can alleviate gastrointestinal reactions. Occasionally, it can cause hyperpigmentation, chapped lips, thinning nails, hair loss, decreased white blood cells, and mild liver function damage.

　　⑥ Currently, other drugs used in the treatment of psoriasis include azathioprine, mycophenolic acid, IMPDH inhibitor VX497, anti-CD4, CD11a, IL-8 antibodies, and DAB389 adalimumab (IL-2), CTLA4-Ig, all of which act by inhibiting immune activity, but they are all still in the initial stage of clinical trials.

　　(2) Retinoic acid derivatives: These drugs are intermediate metabolites or similar derivatives of vitamin A in the body, mainly affecting epidermal metabolism, promoting the proliferation and differentiation of epidermal cells, keratolysis, and maintaining the normal structure of the skin. They are used to treat various types of psoriasis, especially erythrodermic psoriasis, localized or generalized pustular psoriasis. The main side effect of this class of drugs is teratogenicity. During the course of taking the medication, there may be dryness of the lips, eyes, and nasal mucosa, generalized desquamation, fissures, and itching of the skin. Hair loss and epistaxis may occur occasionally, and some patients may have gastrointestinal reactions. Long-term use may lead to increased triglycerides and cholesterol, liver damage, and other conditions, which can return to normal after discontinuation of the drug. Therefore, this class of drugs is not recommended for pregnant women and lactating women. Patients with impaired liver and kidney function, hypervitaminosis, hyperlipidemia, and those allergic to this class of drugs should not use them, and they should not be taken with vitamin A, phenobarbital, or tetracyclines. Commonly used drugs include 13-cis-retinoic acid, etretinate, isotretinoin, and ethyl esters of aromatic retinoic acid, etc.

　　① First-generation retinoids: 13-cis retinoic acid, dosage: the initial dose is 0.5-1mg/(kg?d), reduced to 0.1-1.0mg/(kg?d) after 4 weeks according to the condition, maintenance treatment for 16 weeks, the condition can still improve after discontinuation, and the next course of treatment can be started after 8 weeks if needed.

　　② Second-generation retinoids: Avita (tigason) has achieved outstanding results in the treatment of pustular and erythrodermic psoriasis. The conventional dose is 1mg/(kg?d). However, different dosages should be used for different types of psoriasis: the commonly used dose for寻常型银屑病 is 0.5mg/(kg?d), which can be increased to 1mg/kg at most; for pustular psoriasis, the starting dose should be larger, generally 1-2mg/(kg?d), and after the condition is controlled, the dose can be reduced by 1-3 times per 1-3 weeks; for erythrodermic psoriasis, the starting dose should be lower, as patients have a better response to small doses (25-35mg/d or 0.3-0.4mg/(kg?d)) and long-term treatment (8-10 weeks); it can also start with a small dose and gradually increase to 50-60mg/d after 3-5 weeks. The main side effect is teratogenicity, and the half-life of the drug is 120-140 days, and the drug can still be detected in the urine after 2 years of taking the drug, so women of childbearing age should take contraception measures within 2 years after discontinuation. Avita is the metabolite of Avita ethyl carbonic acid, which has rapid oral absorption and rapid distribution, and its bioavailability is 10 times higher than that of Avita ethyl carbonic acid, but its half-life is 50h, significantly shorter than that of Avita ethyl carbonic acid (etretinate). Dosage: 25-75mg/d, taken in divided doses.

　　③ Third-generation retinoids: Ethyl esters of aromatic retinoids, starting dose 0.1mg, taken at dinner time, twice a week or 0.03mg taken at dinner time once a day, maintenance dose 0.1mg, taken at dinner time, once a week or 0.03mg taken at dinner time every other day.

　　(3) Antibiotics: For patients with active stage of寻常型银屑病 and punctate psoriasis, accompanied by tonsillitis and infection, penicillin and erythromycin can be used.

　　(4) Corticosteroid hormones: Corticosteroid hormones can often improve the skin lesions of psoriasis, but they cannot prevent recurrence. It is not suitable for寻常型银屑病. Generally, it is only used for patients with erythroderma type, arthropathy type, or generalized pustular psoriasis, and when other drugs are ineffective, or for those with systemic toxic symptoms, it can be used for a short period of time. Clinically, this product is often used in conjunction with other therapies to consolidate or maintain symptom relief. When used in combination with immunosuppressants and retinoids, the dosage can be reduced. The commonly used prednisone (prednisone) is 40-60mg/d, taken in divided doses. Currently, it is not recommended to use corticosteroids internally, as the effective dose is often high enough to cause serious side effects, and there may still be a 'rebound' phenomenon after dosage reduction or discontinuation.

　　(5) Mefenamic acid: Mefenamic acid is effective for treating pustular psoriasis with fast onset of action, high efficacy, and few side effects, and is one of the preferred drugs for treating pustular psoriasis at present. It can be taken orally alone (0.5-1g/d for adults, divided into 3-4 times) or combined with corticosteroid treatment. Dosage: 0.25g per time, 4 times a day, which can be increased to 0.5g per time, 3 times a day, or intramuscular injection of 0.4g per time, 2 times a day. The main side effects include bone marrow suppression and gastrointestinal symptoms such as anorexia, nausea, vomiting, abdominal pain, and diarrhea. Caution should be exercised in pregnant women.

　　(6) Vitamin preparations such as vitamin A, vitamin C, vitamin D2, alfacalcidol (alfad3 gelatin capsules) can all be used to treat psoriasis.

　　(7) Immune therapy:

　　① Transfer factor (TF): Effective for psoriasis patients with low cellular immune function. Dosage: 1-2U per time. Once a week, intramuscular injection for one month as one course, or subcutaneous injection on the inner side of the upper arm, once a week for the first two weeks, one vial each time, and then two vials each time, with 10 vials as one course, which can be used for 2-3 courses. Side effects may include lymphoproliferation, rash, fever, and local pain.

　　② Freeze-dried BCG vaccine: Enhances the body's cellular immune function and adjusts humoral immune function. Suitable for papular psoriasis in寻常型 psoriasis. Dosage: 0.5g per time, intramuscular injection 2-3 times per week, with 3 months as one course.

　　③ Vaccine therapy: On the basis of positive skin tests, a single or several vaccines such as short rod bacterium vaccine, Staphylococcus aureus, Streptococcus, Pseudomonas aeruginosa, Proteus, and Candida albicans can be used for weekly injection therapy to improve the body's immune ability and achieve effects. Dosage: Once a week injection is effective, and it can also start with a small amount, 0.5ml per time, and gradually increase to 2.0ml per time, with 10-15 times as one course.

　　In addition, thymosin, immune gamma globulin, lentinan, and Chinese herbs such as ginseng, rehmannia, astragalus, codonopsis, atractylodes, and rubus cordifolius can all improve immune function and can be selected clinically as appropriate.

　　2. Topical treatment

　　Principally, start with mild, non-irritating drugs, and avoid using strong刺激性 drugs during the acute phase to prevent triggering psoriasis; during the stationary phase, stronger drugs can be applied, but should start with low concentrations and increase gradually as appropriate. Topical drugs absorbed over large areas can be more toxic, so it is advisable to divide the skin lesions and apply different drugs. It is best to take a hot water and soap bath before taking medication to remove scales and enhance efficacy. The choice of medication is mainly determined by the type of psoriasis, the severity of the lesions, and their distribution. When selecting topical preparations for psoriasis lesions in the external genital and fold areas, it is advisable to avoid using dirty or strongly irritant preparations, as well as photodynamic therapy.

　　Common topical treatment methods include:

　　(1) Corticosteroid hormones: They have the effects of contracting the dermal blood vessels and inhibiting cell mitosis, especially valuable for psoriasis lesions on areas such as the face and external genitalia that cannot be treated with anthralin and high-concentration tar preparations. They are the most widely used in psoriasis treatment, with significant efficacy and do not stain clothes. Appropriate concentrations of fluorinated corticosteroids should be selected, such as mometasone furoate cream (trade name Elosone, eloson), hydrocortisone (chlorofluorothionate) cream, triamcinolone acetonide (triamcinolone acetonide A), the strongest fluocinolone acetonide cream, super-potent betamethasone propionate, clobetasol propionate, betamethasone dipropionate (trade name Solcom, psorcom), clobetasol (propionate halobetasol), ointments or creams, etc. There are two specific methods of use: single use and intermittent pulse therapy. The single therapy often uses potent corticosteroids, commonly used for relatively small, thick plaque-type lesions on the palms, soles, and limbs. It can also be wrapped, and then switch to medium-to-low intensity corticosteroids after the lesions become thin, usually applied topically twice a day. Intermittent pulse therapy involves the use of potent corticosteroids, twice daily, for 2-3 weeks until the lesions regress by more than 85%, then continue 3 times a week at the weekend, with an interval of 12 hours between each application, i.e., topical application for 3 times within 36 hours. This method can avoid resistance and rebound. Thick plaques require wrapping therapy. However, it should be noted that large-area application can increase absorption, and atrophy may occur at the application site. The combination of corticosteroid hormone preparations with other topical preparations has good efficacy. The common side effects are atrophy at the application site, which can recover after discontinuation. However, long-term topical use of corticosteroids may lead to skin atrophy that is difficult to recover, and large-area long-term use of potent corticosteroid hormones can cause systemic side effects. Discontinuation may induce pustular or erythrodermic psoriasis. Other side effects include telangiectasia, folliculitis, etc.

　　(2) Tretinoin derivatives: The concentration of tretinoin for the topical treatment of psoriasis is 0.025% to 1%, with a commonly used concentration of 0.025% to 0.3%. It can be formulated into solutions, ointments, and gels. Ointments are the most promising for topical treatment of psoriasis. Side effects include erythema, itching, and irritation, which can cause acute and subacute dermatitis at high concentrations. The efficacy also decreases with the reduction of concentration. The third-generation tretinoin receptor selector 0.1% itazalodene gel has good efficacy for the topical treatment of plaque-type psoriasis. When combined with potent corticosteroids, it can achieve better efficacy, reduce the above dosage, and decrease its latent toxicity.

　　(3) Vitamin D3 Analogues: These preparations inhibit keratinocyte proliferation and promote differentiation; they also inhibit the proliferation and differentiation of T lymphocytes, exerting immunosuppressive effects. The commonly used drug is calcipotriol, whose 50μg/g ointment preparation can improve the condition of more than 74% to 96% of patients. Taken twice a day, a course of treatment is 6 weeks, and the treatment area per session should not exceed 40% of the body surface area. When used in conjunction with cyclosporine (CyA), it has a synergistic effect, reduces side effects, and can achieve efficacy in chronic severe cases. Attention should be paid to large-area application or those with mild calcium metabolism disorders. The main side effects are local irritation symptoms around the skin lesions (20%) but are generally tolerable. Only 5% of patients may need to discontinue treatment, and occasionally it can cause allergic contact dermatitis. Caution should be exercised when using calcipotriol on the skin lesions in the facial and body creases. In addition, there are other preparations such as calcitriol (CCT) ointment, tretinoin (tretinol) ointment, KH1060, etc., which are effective for psoriasis skin lesions, but their calcium affinity limits their high-concentration, large-area use. Tretinoin (tretinol) has fewer local irritation symptoms than calcipotriol, around 1%, and can be used on creases or the face.

　　(4) Topical treatment with tacrolimus ointment is effective for smaller plaque-type psoriasis and effective for treating psoriasis in creases. Drugs with similar mechanisms include SDZ281240, SDZASM981, A86281, and other topical preparations for treating psoriasis have achieved initial success.

　　3. Physical Therapy

　　Bath therapy and sweating therapy, dialysis therapy, hyperbaric oxygen therapy, photoquantum blood therapy, and other treatments can also be used for psoriasis. The combination of ultraviolet light, photochemical therapy (PUVA) or PUVA with corticosteroids, methotrexate (MTX), retinoic acid, and other drugs is an effective treatment for psoriasis, but it is not suitable for the treatment of skin lesions in the genital area.