Psoriasis, commonly known as psoriasis, is a common chronic, inflammatory, recurring skin disorder characterized by the appearance of erythematous patches, papules, and plaques of varying sizes covered with silvery-white scales with clear borders, and bleeding spots when the silvery-white scales peel off. It occurs on the scalp, extensor surfaces of the limbs and back. Although psoriasis does not directly affect life, it can have a very serious impact on physical health and mental and physical health.
Causes and pathogenesis of psoriasis
The exact cause of psoriasis is not yet known. It is currently believed that psoriasis is a polygenic genetic disease in which genetic and environmental factors and other factors interact to cause excessive proliferation of keratin-forming cells through a T-cell-mediated immune response.
1, genetic factors: epidemiology, HLA analysis and full gene scan analysis studies all support the genetic predisposition of psoriasis. 20% or so of psoriasis have a family history, when one parent has psoriasis, the incidence of psoriasis in children is about 16%; and when both parents are psoriasis patients, the incidence of psoriasis in children reaches 50%.
Class I antigens A1, A13, A28, B13, B17, B37 and Cw6 and class II antigen DR7 of the HLA system were expressed more frequently in psoriasis patients than in normal subjects, with the Cw6 locus being the most clearly associated with psoriasis. Since 1994, eight loci for psoriasis susceptibility genes have been identified by genome-wide scans located in regions such as 1p, lq, 3q, 4q, 6p, 17q and 19p.
2, environmental factors: genetic factors alone are not enough to cause the onset of psoriasis, environmental factors play an important role in triggering and aggravating psoriasis. Factors that can trigger or aggravate psoriasis include infection, mental stress and stressful events, trauma, surgery, pregnancy, smoking and the effects of certain drugs, etc. Infection has always been considered an important factor in triggering or aggravating psoriasis, for example, there is often a history of acute streptococcal infection in the pharynx before the onset of psoriasis, and the condition often improves after antibiotic treatment is given.
3, immune factors: lymphocyte and monocyte infiltration at the lesions of common psoriasis is obvious, especially T-lymphocyte dermal infiltration is an important pathological feature of psoriasis, indicating that the immune system is involved in the occurrence and development of the disease. It is hypothesized that activated T lymphocytes in the lesions release cytokines (IL-1, -6, -8, IFN-γ, etc.) that stimulate keratinocyte proliferation and promote and participate in the development of psoriasis. An important feature of the pathophysiology of psoriasis is the accelerated proliferation of keratin-forming cells in the basal layer of the epidermis, the shortening of the mitotic cycle to 37.5 hours, the shortening of the epidermal turnover time to 3-4 days, and the histopathological appearance of incomplete keratinization and the disappearance of the granular layer.
What are the clinical manifestations of psoriasis?
According to the clinical characteristics of psoriasis, it can be divided into common type, arthritic type, pustular type and erythrodermic type, among which common type accounts for more than 99%. Other types are mostly transformed from common psoriasis, which can be induced by the external use of stimulating drugs, systematic use of glucocorticoids, sudden discontinuation of drugs during immunosuppression, as well as infection and mental stress.
Psoriasis vulgaris
Arthritic psoriasis
Pustular psoriasis
Erythrodermic psoriasis
Psoriasis vulgaris: The initial lesions are red papules or macules, which gradually expand into red plaques with clear boundaries and can take many forms (such as drip, plaque, coin, map, oyster shell, etc.), covered with thick layers of silvery white scales, scraping away the layers of scales as if lightly scraping wax drops (wax drop phenomenon), and scraping away the silvery white scales to reveal light red glowing Translucent film (film phenomenon), peel off the film can be seen dotted bleeding (Auspitz sign), the latter is caused by the top of the dermal papillae tortuous dilated capillaries are scraped. Wax drop phenomenon, film phenomenon and punctate hemorrhage have diagnostic value for psoriasis. The lesions can occur all over the body but are most common on the extremities, especially on the elbows, knees and sacrococcygeal region, and are often symmetrical, with differences in different parts of the skin.
Psoriasis vulgaris can be divided into three stages according to the development of the disease.
1.Progressive phase: old lesions do not fade, new lesions keep appearing, infiltrative inflammation of the lesions is obvious, there may be a red halo around, and the scales are thicker; injuries such as needling, scratching and surgery can lead to the appearance of typical psoriatic lesions on damaged areas, which is called isomorphism or Kobner phenomenon.
2.Static phase: stable lesions, no new lesions, light inflammation and more scales.
3.Regressive phase: lesions shrink or flatten, inflammation basically subsides, leaving hypopigmentation or hyperpigmentation spots. Acute guttate psoriasis, also known as eruptive psoriasis, is common in young people and often has a history of streptococcal infection in the throat before the onset of the disease. The lesions are 0.3~0.5cm sized papules and macules, flushed and covered with a few scales, with varying degrees of itchiness. With appropriate treatment, the lesions may subside within a few weeks, and a few patients may develop a chronic course.
Differential diagnosis of psoriasis
Diagnosis and typing are mainly based on typical clinical manifestations, and histopathological manifestations have a certain diagnostic value.
Psoriasis should be differentiated from the following diseases.
1. seborrheic dermatitis: distinguish it from scalp psoriasis. The lesions are erythematous with indistinct edges. The hair can be sparse, thinning and falling out, but there is no bundle of hair.
2. Headache: Differentiate from scalp psoriasis. The lesions are covered with grayish white bran-like scales, with hair breakage and hair loss Easy to detect fungi, mostly seen in children.
The typical lesion is a coppery red, infiltrative rash or maculopapular rash on the palmoplantar area, with positive syphilis seropositivity.
4, flat moss: lesions are polygonal flat purple-red papules, can be fused into scaly plaques, mucous membranes are often involved, the course of the disease is chronic.
5, chronic eczema: differentiate from hypertrophic psoriasis lesions occurring on the lower legs, the extensor side of the forearm and the sacrococcygeal region. Eczema often has intense itching, and the skin is infiltrated with hypertrophic, moss-like changes.
Clinical treatment of psoriasis
Treatment of psoriasis can only achieve clinical remission and is not yet curative. Treatment should prohibit irritating topical drugs, as well as drugs that can lead to serious adverse reactions (such as the systematic use of glucocorticoids and immunosuppressants), so as not to aggravate the disease or transform it to other types. The appropriate treatment should be given for different causes, types and stages of the disease, and psychotherapy should be emphasized. Avoid triggering or aggravating factors such as upper respiratory tract infection, exertion and mental tension.
Treatment principles of psoriasis.
The purpose of psoriasis treatment is to control the disease, slow down the process of development to the whole body, reduce symptoms such as erythema, scaling and local patch thickening, stabilize the disease, avoid recurrence, avoid side effects as far as possible and improve patients’ quality of life. Communication with patients and assessment of their conditions during treatment is an important part of treatment. When the effect of single therapy is not obvious in patients with moderate or severe psoriasis, combined, rotating or sequential treatment should be given.
1, topical drug treatment: glucocorticoid cream or ointment has obvious efficacy, should pay attention to its adverse reactions, large area long-term application of strong or super-effective preparations can cause systemic adverse reactions, after stopping the drug can even induce pustular or erythrodermic psoriasis; vitamin A acid cream commonly used concentration of 0.025%-0.1%, of which 0.05% ~ 0.01% tazarotene gel treatment plaque psoriasis efficacy Better; vitamin D3 derivatives such as calcipotriol also have better efficacy, but should not be used on the face and skin folds; various keratin-enabling agents (such as tar preparations, anthralin ointment, 10%-15%0camptothecin ointment, salicylic acid ointment, etc.) can also be used.
2, systemic treatment: retinoic acid drugs are suitable for all types of psoriasis, such as Aveline 0.75~1.0mg/(kg-d) orally; immunosuppressants are mainly suitable for erythrodermic, pustular and arthritic psoriasis. Methotrexate is commonly used in adult doses of 10~25mg per week orally, cyclosporine and tacrolimus are also available; antibiotics should be used for patients with obvious infection or generalized pustular psoriasis; glucocorticoids are generally not advocated for common psoriasis, but mainly used for erythrodermic psoriasis, acute arthritic psoriasis and generalized pustular psoriasis, etc., and can be used in combination with immunosuppressants and retinoids to The dose should be reduced, and should be applied for a short period of time and gradually reduced to prevent rebound; immunomodulators can be used for those with low cellular immune function.
3, physical therapy: such as photochemotherapy (PUVA), UVB phototherapy (especially narrow-wave UVB), bath therapy, etc. can be applied.