bubble_chart Overview

Psoriasis, commonly known as psoriasis, is a chronic and recurrent skin disease characterized by distinctive skin lesions, similar to Chinese medicine psoriasis.

bubble_chart Etiology

The primary feature is marked parakeratosis, with Munro microabscesses visible within or beneath the stratum corneum, formed by the migration and aggregation of neutrophils from the upper dermal papilla into the epidermis. The stratum spinosum is thickened, and the rete ridges extend downward into the dermis. The dermal papillae become club-shaped and protrude upward into the epidermis, approaching the stratum corneum. The blood vessels in the dermal papillary layer are dilated, with endothelial hyperplasia, and are surrounded by a sparse infiltration of lymphocytes.

bubble_chart Clinical Manifestations

Clinically, the disease mostly presents with acute onset and spreads throughout the body. The primary rash consists of inflammatory papules or maculopapules ranging from pinhead to hyacinth bean size, displaying a characteristic light red color with well-defined borders. The surface is covered with multiple layers of silvery-white scales, surrounded by a grade I erythema. Removing the scales reveals a translucent thin membrane (thin membrane phenomenon), and scraping off this membrane results in small bleeding points, known as the Auspitz sign, corresponding to the ruptured dermal papillary tips. This thin membrane phenomenon and the Auspitz sign are distinctive features. Patients may experience varying degrees of cutaneous pruritus. The rash can continuously expand and proliferate, manifesting in various forms such as guttate, nummular, petaloid, or geographic patterns, and rarely in a band-like configuration. It may also coalesce and spread extensively, even covering the entire body. In rare cases, exudative moistening or formation of an oyster-shell-like appearance may occur, termed moist or oyster-shell psoriasis.

Psoriasis can occur anywhere on the body but is most common on the extensor surfaces of the limbs, particularly the elbows and knees, with symmetrical distribution. It is also frequently seen on the scalp and lumbosacral region. Rarely, it may appear in the axillae, groin, and other flexural areas. The palms, soles, nails, and mucous membranes can also be affected. Scalp involvement often appears early in the disease, with clearly demarcated lesions, thickly accumulated scales, and tufted hair growth but no alopecia areata. Lesions often form a band-like pattern along the hairline. Some patients may initially develop scaly patches on the scalp, gradually extending to the limbs or the entire body. Flexural psoriasis presents with thinner scales and distinct borders, often showing eczematous changes due to sweat maceration and scratching. Psoriasis of the palms and soles is rare, characterized by well-defined yellowish-brown hyperkeratotic patches surrounded by erythema, with thick scales that, when removed, reveal cup-shaped depressions. Rhagades are more likely to form in these areas.

Throughout the course of the disease, the lesions typically remain dry, except in oyster-shell or flexural psoriasis, and generally do not tend to become moist or develop secondary vesicles or pustules, nor do they involve internal organs.

Nail psoriasis is common. The most frequent manifestation is "thimble-like" pitting of the nail plate. In more severe cases, the nail surface loses its luster, appearing dull yellow, thickened, and brittle, with longitudinal ridges or transverse fissures. Over time, the nail may be destroyed or lost. If all fingernails or toenails are affected, the finger joints may exhibit intense inflammatory reactions.

In rare cases, psoriasis may involve the lips, glans penis, or other areas, presenting as well-defined light red infiltrated patches with a dry surface and inconspicuous scales, but scraping reveals silvery-white scales.

The course of psoriasis is generally divided into three stages.

1. **Stage of progression**: Lesions show marked infiltration and thick scales, surrounded by erythema. Various mechanical stimuli such as needling, scratching, or application of strong medications can induce new lesions at the stimulated sites, known as the isomorphic reaction (Koebner phenomenon).
2. **Stable or stationary stage**: The condition stabilizes, with no further progression, reduced inflammation, and minimal new lesions.
3. **Stage of regression (stage of convalescence)**: Inflammation of the lesions largely subsides, with shrinkage and flattening, surrounded by a light-colored halo that gradually expands. The rash resolves, leaving light-colored patches, achieving clinical cure. Some lesions may regress centrally in an annular pattern. Systemic or topical antineoplastic agents such as methotrexate or topical mustard seed ointment may leave post-treatment hyperpigmentation. Lesions on the lower limbs and scalp often resolve later.

Psoriasis may spontaneously remit during its prolonged course but is prone to relapse. Recurrence and exacerbation are common in winter, while improvement and remission often occur in summer. Emotional distress, psychological trauma, cold, dampness, alcohol consumption, or excessive fatigue may trigger relapse or worsening of the condition.

bubble_chart Diagnosis

The diagnosis is generally straightforward based on the characteristics of the skin lesions, common affected areas, chronic course, tendency to recur, and histopathological features. Differential diagnosis relies on the above diagnostic criteria, making it easy to distinguish from other skin diseases. However, when localized to a single area with atypical symptoms—such as scalp psoriasis versus seborrheic dermatitis of the scalp—the latter lacks tufted hair and the Auspitz sign, exhibits milder basal infiltration, and shows no psoriatic lesions elsewhere on the body. Psoriasis of the glans penis should be differentiated from lichen planus of the glans penis, which presents as annular lesions composed of purplish-red polygonal papules with a pearly sheen, minimal scaling, and often involves the oral mucosa. Psoriasis in flexural areas should be distinguished from acute or subacute eczema, where cutaneous pruritus is intense and moisture is prominent. Although axillary psoriasis may also appear moist, applying powder to dry the area will reveal typical psoriatic lesion features. Chronic hypertrophic psoriasis of the lower legs should be differentiated from neurodermatitis of the lower legs, which shows lichenification without multilayered scaling or the Auspitz sign, and histopathology reveals only slight parakeratosis.

bubble_chart Treatment Measures

Currently, there is no specific cure for psoriasis. All existing treatments can only achieve short-term effects and cannot prevent recurrence.

1. General Therapy

Relieve psychological concerns, eliminate emotional trauma, and avoid various triggering factors. Avoid misuse of medications, especially during the acute stage of progress, where strong irritant drugs, ultraviolet radiation, hot soapy water baths, etc., should be avoided.

2. Topical Drug Therapy

When applied appropriately, it can yield relatively good short-term effects for psoriasis. Commonly used agents include:

1. Keratoplastic Agents: These drugs not only stimulate the skin and improve local microcirculation but also interfere with RNA synthesis, inhibit protein synthesis, and reduce mitotic activity. Under ultraviolet light, they also inhibit DNA synthesis. For common psoriasis, tar preparations (such as 5–10% black soybean distillate, pityrol, pine tar, coal tar, etc.), 5–10% sulfur, 5% salicylic acid, 5% ammoniated mercury, 1–2% pyrogallol acid, 0.1–0.4% anthralin, or mustard gas can be formulated into ointments or pastes. Tar and anthralin can also be combined with corticosteroids. Anthralin has strong irritant effects and may cause erythema, burning pain, and severe itching; it should be used cautiously in skin folds. Mustard gas is commonly used in 1:20,000 to 1:10,000 ointments, suitable for the stable and convalescent stages of common psoriasis. This drug is highly irritating and contraindicated during the acute stage of progress. It also irritates mucous membranes and is best avoided on the head and face. Patients with liver or kidney diseases should not use it.
2. Corticosteroid Creams: These can be applied topically, under occlusion, or combined with tar preparations for better effects. For chronic localized lesions, prednisolone acetate mixed with an equal volume of 1% procaine solution can be injected into or under the lesion.

3. Systemic Therapy

1. Immunosuppressants: Considered when lesions are widespread and topical treatments are ineffective. Commonly used agents include methotrexate (MTX), ethylenediamine, bimolane, and hydroxyurea. These drugs have many adverse effects, so their dosage and administration must be strictly controlled, and regular laboratory tests should be performed before and after treatment. Ethylenediamine and bimolane can be used for common psoriasis under strict dosage control, while other immunosuppressants are reserved for cases unresponsive to ethylenediamine and bimolane, as well as severe pustular and arthritic psoriasis.
2. Retinoids: Aromatic retinoids show some efficacy.
3. Antibiotics: Commonly used include penicillin and newer penicillins, suitable for acute guttate psoriasis accompanied by tonsillitis or pharyngitis.
4. Corticosteroids: Used for erythrodermic, arthritic, or generalized psoriasis when other treatments fail. Contraindicated in common psoriasis.

In addition to the above drugs, intravenous procaine infusion (240mg procaine and 100mg vitamin C in 500ml of 5% glucose solution, once daily for 7–10 days as a course) can be used during the acute stage of progress and for erythrodermic psoriasis. For chronic stable cases, anaerobic Corynebacterium parvum vaccine injections may be tried.

4. Physical Therapy

Common methods include balneotherapy, phototherapy, and photochemotherapy.

1. Balneotherapy: Common options include sulfur baths, bran baths, tar baths, mineral baths, seawater baths, and Chinese herbal baths, which stimulate the skin, improve circulation, and reduce inflammatory infiltration. Chinese herbal baths often use pricklyash peel, dried alum, Platycladus, and paper mulberry leaves, among others. A decoction of 120g each of pricklyash peel and dried alum, 250g of wild chrysanthemum flower, and 500g of mirabilite in water can be used for full-body baths, showing good efficacy for common and erythrodermic psoriasis.
2. Phototherapy: Primarily involves ultraviolet therapy, which can be used alone as ultraviolet irradiation, or combined with drugs and ultraviolet irradiation, or external application of tar-based medications plus ultraviolet irradiation, followed by hydrotherapy (Godckerman triple therapy).
3. Photochemotherapy: Mainly involves oral or topical administration of 8-methoxypsoralen (8-MOP), followed by irradiation with long-wave ultraviolet (UVA) (PUVA). Preventive measures against {|###|}internal visual obstruction{|###|} must be taken, such as wearing UVA-protective goggles for 24–48 hours after taking 8-MOP, and monitoring for secondary {|###|}skin cancer{|###|} tumors. It is contraindicated for patients with photosensitivity, severe organic diseases, or during {|###|}pregnancy{|###|}.

V. {|###|}Chinese medicine{|###|} Therapy

Domestic experience has shown promising results, including both pattern identification-based treatments and the use of single-herb {|###|}Chinese medicinals{|###|}. For the acute {|###|}stage of progress{|###|}, especially the acute guttate type accompanied by tonsillitis or pharyngitis, the treatment principle focuses on clearing heat, {|###|}cooling blood{|###|}, resolving macules, dispersing stasis, dispelling wind, and relieving itching. Prescriptions such as {|###|}Indigo{|###|} Drink, {|###|}Arnebia{|###|} Macule-Resolving Decoction, and {|###|}cooling blood{|###|} Wind-Dispersing Decoction may be modified for use. For the stable stage, if the {|###|}tendency of disease{|###|} persists with spleen dampness and stomach heat, Dampness-Expelling Stomach Poria Decoction may be modified; for cases with {|###|}qi stagnation and blood stasis{|###|} or {|###|}menstrual irregularities{|###|}, Peach Kernel, Carthamus and Four-Ingredient Decoction may be modified. Compound formulas such as {|###|}Indigo{|###|} Pill, {|###|}Curcuma Root{|###|} Psoriasis Tablets, {|###|}Salvia{|###|} Tablets, and {|###|}Root Leaf or Flower of Common Threewingnut{|###|} Tablets, taken orally, have shown certain efficacy. Single {|###|}Chinese herbal medicines{|###|} include {|###|}Salvia{|###|}, {|###|}Chinese Angelica{|###|}, Smilax glabra, {|###|}Isatis Root{|###|}, dock root, Sparganium, and zedoary. For erythrodermic or acute generalized cases, the principle is {|###|}clearing heat and cooling blood{|###|}, and prescriptions such as Coptis Detoxification Decoction or Five-Ingredient Toxin-Eliminating Decoction may be modified. For pustular psoriasis, the principle is {|###|}clearing heat and removing toxin{|###|}, and prescriptions such as Gentian Liver-Draining Decoction combined with Five-Ingredient Toxin-Eliminating Decoction may be modified. For arthropathic psoriasis, the principle is regulating and tonifying the liver and kidneys, {|###|}invigorating the blood to unblock collaterals{|###|}, and prescriptions such as Pubescent Angelica and Taxillus Decoction or Two-Solstice Pill may be modified.