Psoriasis is a persistent skin lesion characterized by thick white scales on the skin accompanied by itching.

Zhubing Yuanhou Lun describes psoriasis as "having defined borders, with dry and itchy skin that produces white scales when scratched." Yizong Jinjian refers to psoriasis as "resembling a rash or scabies, white in color and itchy, with white scales appearing when scratched." Waike Zhengzhi Quanshu calls it "skin wind," stating, "the skin becomes dry and itchy, developing a rash-like appearance that is white, with scales rising when scratched, gradually leading to dryness and cracking of the limbs, with pain and bleeding." Terms like "psoriasis" and "skin wind" are synonymous with psoriasis.

Chinese medicine believes that this disease is generally caused by a deficiency of nutrient-blood, leading to the generation of wind and dryness, and the loss of nourishment to the skin. Initially, it is often accompanied by the invasion of wind-cold, wind-heat, or wind-dampness evils into the skin, resulting in disharmony of nutrient-defense, obstruction of qi and blood, and blockage at the skin surface. Alternatively, it may be due to the accumulation of dampness-heat, with deficient dispersion and drainage, leading to blockage at the skin surface. Over time, the evils of wind-cold, wind-heat, and dampness-heat transform, and the consumption of qi and blood leads to blood deficiency and wind-dryness, further depriving the skin of nourishment. It can also be caused by insufficient nutrient-blood, obstruction of qi and blood circulation, leading to phlegm blockage at the skin surface; or due to liver and kidney deficiency, disharmony of the Chong and Ren meridians, and deficiency of nutrient-blood. A few cases are due to improper treatment, combined with the invasion of toxic evils, transformation of wind-cold into heat, and dampness into dryness, resulting in dryness-heat becoming toxic, heat toxin entering the nutrient level, and invading the zang-fu organs, causing a blazing of both qi and blood. In summary, the causes of this disease are related to wind, heat, cold, blood heat, blood dryness, blood stasis, and liver and kidney deficiency.

Psoriasis is a chronic, recurrent, common skin disease characterized by excessive proliferation of epidermal cells, commonly known as "psoriasis". The skin lesions are red papules or patches, covered with multiple layers of shiny silvery-white scales, with clear boundaries, mostly occurring on the extensor surfaces of the limbs and the scalp. It can affect people of all ages, with a higher prevalence among young adults, approximately 0.12%. It is more common in males than females, in urban areas than rural areas, and in the north than in the south.

The disease cause and mechanism of psoriasis are related to genetic factors, immune dysfunction, epidermal growth disorders, viral or streptococcal infections, and psychological factors. In recent years, with the continuous development of skin immunology, it is believed that the pathogenesis of psoriasis may involve various unknown antigens that activate macrophages and dermal T cells, leading to the production of γ-interferon, which binds to receptors on keratinocytes, thereby inducing the expression of HLA-DR and ICAM-1 on keratinocytes. Keratinocytes can produce various cytokines, such as interleukin-8, interleukin-3, interleukin-6, interleukin-8, TNF, and various colony-stimulating factors, promoting the growth of peripheral blood monocytes and lymphocytes, and triggering a series of immune responses.

[Diagnosis]

1. Psoriasis vulgaris: accounts for the vast majority of cases.
   1. The basic lesion is a red papule, which can merge into patches with clear edges, covered with multiple layers of silvery-white scales, exhibiting the phenomena of stearin spots, thin membranes, and punctate bleeding.
   2. According to the activity of the lesions, it can be divided into the progressive stage, stationary stage, and regressive stage, with isomorphic reactions possible in the progressive stage.
   3. Lesions commonly occur on the scalp and extensor surfaces of the limbs, but can also spread throughout the body.
   4. Some patients may have nail lesions and mucous membrane lesions. In the initial stage [first stage], the nail plate shows punctate depressions; in the late stage [third stage], the nail plate thickens, loses its luster, and separates from the nail bed.
   5. The course of the disease is slow and prone to recurrence.
   6. Histopathological examination reveals parakeratosis, microabscesses in the stratum corneum, acanthosis, regular downward extension of rete ridges, club-shaped papillae, and tortuous and dilated capillaries within.
2. Pustular psoriasis
   1. There are two types: palmoplantar pustular psoriasis and generalized pustular psoriasis.
   2. The basic lesion is a pustule, with pinhead-sized superficial pustules that can occur on lesions of psoriasis vulgaris or on non-lesional skin, with negative bacterial cultures.
   3. It is often accompanied by nail lesions.
   4. It may initially present as psoriasis vulgaris or be accompanied by joint and systemic symptoms.
   5. Histopathology shows large spongiform pustules in the stratum corneum; severe inflammatory infiltration in the dermis, mainly consisting of lymphocytes, histiocytes, and a small number of neutrophils.
3. Psoriatic arthritis
   1. Mostly affects small joints, occasionally involving large joints such as the elbows and knees. The clinical presentation is similar to rheumatoid arthritis, with severe cases leading to stiffness and deformity.
   2. X-rays show cartilage loss, joint surface erosion, narrowing of joint spaces; osteoporosis and cystic changes, and soft tissue swelling.
   3. It is often accompanied by the aforementioned skin lesions, especially in exudative and pustular types.
   4. The joint disease is related to psoriasis skin lesions and has a parallel relationship.
4. Erythrodermic psoriasis
   1. There is a history of psoriasis, with skin lesions showing diffuse erythematous infiltration throughout the body, with a large amount of bran-like scales and residual normal "islands" of skin.
   2. The course is slow, with recurrent episodes, leading to patient debilitation and susceptibility to various complications.
   3. This type often develops from psoriasis due to irritation or improper treatment.

Psoriasis needs to be differentiated from chronic eczema, pityriasis rosea, seborrheic dermatitis, psoriasis-like syphilis rash, and other diseases.

bubble_chart Pattern Analysis

1. Blood Heat︰The rash develops rapidly, with skin flushing or slight swelling, increased but not thick scales, mostly appearing as droplet-shaped, erythema or maculopapules. The surface scales are multilayered, easily peeled off when scratched, with the underlying layer adhering more tightly. Forcible peeling reveals punctate bleeding on the base, accompanied by noticeable itching. It is often associated with irritability, thirst, dry stools, and dark urine. The tongue is red with a white or yellow coating, and the pulse is wiry-slippery or wiry-rapid. This condition is commonly seen in the progressive stage of the disease, primarily caused by accumulated heat in the heart and liver meridians stagnating in the blood aspect, which scorches the skin. The skin lesions are characterized by rapid onset, obvious redness at the base, numerous scales on the surface, and punctate bleeding upon peeling. Treatment should focus on clearing the nutrient aspect, cooling the blood, and promoting blood circulation. The recommended formulas are the Blood-Cooling and Blood-Activating Decoction with modifications or the Ecchymosis-Dissipating Decoction with modifications. Ingredients include Unprocessed Rehmannia Root (15g), raw Gypsum (30g, to be decocted first), Lalang Grass Rhizome (30g), Moutan Bark (15g), Red Peony Root (10g), Salvia (20g), Lonicera (15g), Forsythia (15g), Dyers Woad Leaf (15g), Isatis Root (15g), and Arnebia (15g). For severe constipation, add raw Rhubarb Rhizome (10g, to be decocted later).
2. Blood Dryness︰The rash develops slowly, remains stable, and has a prolonged course. The skin is dry, and the lesions are pale in color, mostly appearing as light red patches with noticeable infiltration. There is not much scaling on the surface, and it adheres firmly. New rashes are relatively few. The tongue texture is pale or has a white coating, and the pulse is deep and slow or thin and slow. This condition is commonly seen in the stationary stage. It is often caused by deficiency of yin blood or prolonged stagnation of toxic heat damaging yin and blood, leading to malnutrition of the skin. The characteristics of the rash include a light red color, forming infiltrated patches with dry, thin, and sparse scaling on the surface. Treatment should focus on nourishing blood, enriching yin, and moisturizing the skin. The recommended formula is the Nourishing Blood and Moistening Skin Decoction with modifications, or the Four Ingredients Decoction with modifications. Ingredients include Unprocessed Rehmannia Root 10g, Prepared Rehmannia Root 10g, Moutan Bark 10g, Red Peony Root 10g, Black Sesame 15g, Chinese Angelica 10g, Salvia 15g, Densefruit Pittany Root-bark 10g, and Suberect Spatholobus Stem 30g.
3. Blood Stasis︰The skin lesions are thick, stubborn, and hard, feeling like rotten wood when scratched. The rashes mostly appear as dark red patches, with possible pigmentation, and may be accompanied by restricted joint movement. Some rashes merge into map-like patterns, with large, tightly adherent scales on the surface. The course of the disease is prolonged and recurrent, with large fused rashes often showing cracks or pain. The tongue texture is purplish-dark or has ecchymoses and petechiae, with little coating, and the pulse is choppy, fine-choppy, or fine-slow. This is mostly caused by qi-blood deficiency, leading to stagnation of qi and blood, resulting in malnutrition of the skin. The characteristic of the lesions is large, thickened patches, mostly dark red, with thick and tightly adherent scales, and a prolonged course. Therefore, treatment should focus on invigorating blood and resolving stasis to move qi, using modified Invigorating Blood and Resolving Stasis Decoction; or promoting blood circulation to resolve phlegm, dispelling wind and moistening dryness, with modified Peach Kernel, Carthamus, and Four-Ingredient Decoction: Peach Kernel 10g, Carthamus 10g, Chinese Angelica 10g, Red Peony Root 10g, Prepared Rehmannia Root 10g, Salvia 15g, Sparganium Rhizome 10g, Zedoary Rhizome 10g.
4. Dampness-heat︰The rash often presents as dark red patches of varying sizes, with a greasy or thick crust-like scale on the surface. Beneath the scale, there may be grade I exudation or moist surfaces, sometimes developing pustules, and in severe cases, merging into larger areas. It commonly occurs on the limbs, palms, soles, trunk, and skin folds. The tongue coating is white and greasy or yellow and greasy, with a deep and slow or deep and wiry pulse. This condition is usually caused by the accumulation of dampness-heat in the body, which transforms into toxins and manifests on the skin. The lesions are characterized by dark red patches with greasy scales or thick crusts, often accompanied by grade I exudation or pustules beneath the scales. It can appear on the palms, soles, or spread across the body. Treatment should focus on clearing heat, dispelling dampness, and removing toxins. The recommended formula is the Clearing Heat and Dispelling Dampness Decoction with modifications.
5. External Contractionwind-cold︰The skin lesions show faint red patches with thick, white scales that are easily scraped off, worse in winter and better in summer, often accompanied by aversion to cold, joint soreness, and mild cutaneous pruritus. The tongue coating is thin and white, and the pulse is rough or soggy. This condition is commonly seen in children and those with early-stage illness. The treatment principle is to dispel wind and cold while nourishing blood to moisten dryness. Modified Cinnamon Twig Decoction is used: Cinnamon Twig 10g, Peony Root 10g, White Atractylodes 10g, Fresh Ginger Rhizome 3 slices, Prepared Liquorice Root 10g, Densefruit Pittany Root-Bark 15g, Chinese Angelica 10g, Suberect Spatholobus Stem 15g, Black-Tail Snake 3g (powdered and taken orally). For cases with joint deformities and limited mobility, consider adding Notopterygium, Pubescent Angelica, Chinese Taxillus Herb, Gentian, Mulberry Twig, and Chinese Clematis Root.
6. Toxic Heat︰The onset is sudden, often merging and spreading throughout the body. The skin becomes diffusely flushed or dark red, and in severe cases, pustules erupt all over, accompanied by a large amount of fine bran-like scaling or large patches of deciduous scaling. There is a burning sensation with itching and pain, and it may be accompanied by fever, aversion to cold, high fever, thirst, dry lips and tongue, dysphoria, restlessness, dry stools, dark urine, a crimson tongue texture, yellow, rough, or greasy yellow tongue coating, and wiry-slippery, slippery-rapid, or wiry-rapid pulses. This condition is commonly seen in pustular or erythrodermic psoriasis. It is often caused by internal accumulation of dampness-heat that transforms into toxins over time, or by exposure to external pathogenic toxins leading to intense toxic heat. The skin lesions are characterized by diffuse erythema, burning heat, and extensive scaling. The treatment principle focuses on clearing heat and cooling blood, removing toxins, and eliminating dampness. The recommended formulas are the modified Removing ToxinNutrient-Clearing Decoction or a combination of Rhinoceros Horn and Rehmannia Decoction and Coptis Detoxification Decoction. The herbal prescription includes: Unprocessed Rehmannia Root 15g, Tree Peony Bark 15g, Red Peony Root 15g, buffalo horn 30g (to be decocted first), Salvia 15g, Arnebia 15g, Coptis Rhizome 6g, Skullcap Root 10g, Phelloendron Bark 10g, Gardenia 10g, Lonicera 30g, Forsythia 30g, Glabrous Greenbrier 30g, Dandelion 30g. For significant cutaneous pruritus, add Sophora 15g, belvedere fruit 15g, and densefruit pittany root-bark 15g. For severe constipation, add raw Rhubarb Rhizoma 10g (to be decocted later).
7. Cold-dampness Obstruction︰The skin lesions may present as large dark red patches or droplet-like lesions with minimal surface scaling, or they may form thicker crust-like scales. They are often accompanied by joint pain, frequently affecting the small joints of the fingers and toes, and tend to worsen in cold seasons. In some cases, joint deformities may occur. The pulse is often deep and slow or deep and thin, with a pale tongue texture and scant coating. This condition is mostly caused by the obstruction of meridians by cold-dampness pathogens, leading to stagnation and disharmony of qi and blood. The skin lesions are typically dark red and are characterized by frequent joint involvement, commonly manifesting as swelling, pain, and deformity of the small joints in the hands and feet. Treatment should focus on warming the meridians and dissipating cold, eliminating dampness and unblocking collaterals. The recommended formula is Pubescent Angelica and Taxillus Decoction with modifications.
8. Liver and Kidney Deficiency︰The skin lesions are pale with few scales, appearing grayish-white, accompanied by dizziness, tinnitus, soreness in the waist and weakness in the legs, or impotence and seminal emission, or menstrual irregularities, or joint swelling and pain. The tongue is pale and swollen with a thin coating, and the pulse is thready. The treatment principle is to tonify the liver and kidneys, dispel wind, and moisten dryness. Modified Left-Restoring Decoction is used: Prepared Rehmannia Root 15g, Chinese Angelica 10g, Peony Root 10g, Prepared Fleeceflower Root 10g, Solomonseal Rhizome 15g, Dodder Seed 15g, Barbary Wolfberry Fruit 15g, Donkey-hide Gelatin 10g (melted).