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Psoriasis: causes, symptoms, treatment
Last reviewed: 22.11.2021
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Psoriasis (synonym: scaly lichen) is an inflammatory disease that is most often manifested in the form of clearly limited erythematous papules or plaques covered with silvery scales. What causes psoriasis is unknown, but common causes are injuries, infections and the use of certain medicines.
Subjective psoriasis symptoms are usually minimal, occasionally there is a mild itching, however cosmetically the rashes can create a problem. Some patients develop painful arthritis. The diagnosis of psoriasis is based on the appearance and localization of the rashes. In the treatment of psoriasis, emollients, vitamin D analogues, retinoids, tar, glucocorticoids, phototherapy, and in severe cases methotrexate, retinoids, biological substances or immunosuppressants are used.
Psoriasis is a chronically relapsing disease, which is based on increased proliferation and impairment of differentiation of epidermal cells. The disease lasts for years, accompanied by alternating relapses and remissions.
Psoriasis is a chronic inflammatory dermatosis of multifactorial genesis, in which the genetic component plays a leading role. Psoriasis is characterized by a pronounced spectrum of clinical manifestations: from single, copiously flaky papules or plaques of pinkish red to erythroderma, psoriatic atropathy, generalized or limited pustular psoriasis. Eruptions can be located on any part of the skin, but most often - on the extensor surface of the limbs, scalp, trunk. Psoriatic papules are diverse in size, intensity of inflammatory reaction, infiltration, which can be very significant and accompanied by papillomatous and warty growths.
About 2% of the world's population suffers from psoriasis, men and women are approximately the same.
[What causes psoriasis?
Psoriasis - hyperproliferation of epidermal keratinocytes, accompanied by inflammation of the epidermis and dermis. The disease affects about 1-5% of the world population, in the group at high risk are people with fair skin. The age debut of the disease has two peaks: the most common psoriasis occurs between the ages of 16-22 or 57-60 years, but it is possible at any age. What causes psoriasis is known, but is usually traced in a family history. HLA-antigens (CW6, B13, B17) are associated with psoriasis. It is assumed that the influence of external factors causes an inflammatory reaction and the subsequent hyperproliferation of keratinocytes. It is well known that psoriasis is caused by such facets as: skin lesions (Köbner phenomenon), erythema sun, HIV, beta-hemolytic streptococcal infection, drugs (especially beta-blockers, chloroquine, lithium, angiotensin converting enzyme inhibitors, indomethacin, terbinafine, and alpha- interferon), emotional stress and alcohol.
Psoriasis: skin pathology
Significant acanthosis, the presence of elongated thin and somewhat thickened in the lower part of the epidermal outgrowths; over the tops of the papillae of the dermis, the epidermis is thinned, sometimes consisting of 2-3 rows of cells. Parakeratosis is characteristic, and in the old foci - hyperkeratosis; often the stratum corneum is partially or completely exfoliated. The granular layer is unevenly expressed, as a rule, under the parakeratosis sites. During the progression in the spinous layer, inter- and intracellular edema, exocytosis with the formation of focal aggregations of neutrophilic granulocytes, which migrate to the stratum corneum or parakeratotic regions, form Munro's microabscesses. Mitoses are often found in the basal and lower rows of thorny layers. In accordance with the lengthening of the epidermal processes, the papillae of the dermis are enlarged, bulbous, dilated, edematous, the capillaries in them are convoluted, overflowing with blood. In the podsocochkovom layer, in addition to dilated vessels, there is a small perivascular infiltration from lymphocytes, histiocytes with the presence of neutrophilic granulocytes. Exudative psoriasis exocytosis and intercellular edema in the epidermis are pronounced, which leads to the formation of Munro microabscesses. In the regressing stage of the process, the listed morphological features are much less pronounced, and some are completely absent.
In psoriatic erythroderma, there are typical histological changes in psoriasis, however, in some cases, there is a marked inflammatory reaction with the presence of inflammatory infiltrate of eosinophilic granulocytes among the cells. Sometimes there is spongiosis and vesiculation. In addition, flakes are often poorly attached to the zidermis and, when processed, are separated with microabscesses.
Pustular psoriasis is characterized by the defeat of the skin of the palms and soles, the generalized form of the disease is much less common. Exudative inflammatory reaction, accompanied by vesiculation, is so pronounced that sometimes obscures the typical histological signs of psoriasis. As a rule, there are a lot of Munro microbes that are not only under the horny, but also in the malpighian layer of the epidermis. The histological picture of acute generalized pustular psoriasis of Numbusha is characterized by the presence of subthreshold pustules and destruction of the upper sections of the spiny layer infiltrated with neutrophilic granulocytes with the formation of spongiform neoplasm Kogoy. In assessing the histological changes in the skin with generalized pustular psoriasis, there are disagreements. Some authors consider the characteristic feature of this process the presence of histological signs of psoriasiform acanthosis and hyperkeratosis, others - changes that differ from psoriasis. The most characteristic common histological feature of the pustular forms of psoriasis is spongioformic Kogoy pustules, which are small cavities in the spiny layer, filled with neutrophilic granulocytes. In such cases, it is necessary to conduct differential diagnosis of pustular psoriasis from herpetiform impetigo, gonorrheal keratosis, Reiter's disease, and Sneddon-Wilkinson's subcorneal pustule.
Verruxious psoriasis, in addition to acanthosis, parakeratosis, inter- and intracellular edema of the Malpighian layer, has papillomatosis and hyperkeratosis, as well as a pronounced exudative component with exocytosis and the formation of numerous Myrono microabscesses, in the zone of which there can be massive layers of horny scales and crusts. In the dermis, a vascular reaction is usually pronounced with the swelling of the walls of the vessels, their loosening and the emergence from the lumens of the vessels of the shaped elements. The dermis, especially in the upper parts, is sharply edematous.
Psoriasis: histogenesis
Until now, the issue of the leading role of epidermal or dermal factors in the development of the disease has not been resolved, but the main role, as a rule, is assigned to epidermal disorders. It is assumed that there is a genetic defect in the keratinocytes leading to hyperproliferation of the epidermal cells. At the same time, dermal changes, especially vascular changes, are a more permanent feature of psoriasis, they appear earlier than epidermal and persist long after treatment. Moreover, dermal changes are detected in the clinically healthy skin of patients and their relatives of the 1st degree of kinship. With a clinical recovery from psoriasis, only the epidermal disorders are normalized, and the inflammation in the dermis, especially in the vessels, is observed.
For many years, the role of biochemical factors (caylones, nucleotides, metabolites of arachidonic acid, polyamines, proteases, neuropeptides, etc.) has been studied, but none of the detected biochemical disorders is etiologic.
The contribution to the study of immune mechanisms in the development of the inflammatory reaction is considerable. It is assumed that the emergence of a cellular infiltrate, consisting predominantly of the CD4 subpopulation of T lymphocytes, is the primary reaction. The genetic defect can be realized at the level of antigen presenting ducts, T-lymphocytes, which leads to a different, than normal, production of cytokines, or at the level of keratinocytes pathologically reacting to cytokines. As a confirmation of the hypothesis about the important role in the pathogenesis of psoriasis of activated CD4-subpopulakia T-lymphocytes, the positive effect of the use of myoclonal antibodies to CD4 T-lymphocytes, the normalization of the ratio of CD4 + / CD8 + T-lymphocyte subpopulations after treatment of psoriasis.
The histogenesis of generalized pustular psoriasis is also unclear. In those cases when it develops as a result of the use of drugs, the role of an immediate-type hypersensitivity reaction is assumed. The important role of immune system disorders is indicated by changes in the vessels at pustules, the presence of IgG, IgM, IgA and C3 complement components in the pustules, and in the epidermal basement membrane - the complementary C3b com- ponent, the change in surface receptors of neutrophilic granulocytes obtained from pustules, insufficiency of the T-system of immunity, a decrease in the ratio of T-helpers / T-suppressors and the activity of natural killers in the blood.
Symptoms of psoriasis
The lesions are either not accompanied by subjective sensations, or there is slight itching, and most often they are localized on the scalp, extensor surface of the elbows and knee folds, on the sacrum, buttocks and penis. Nails, eyebrows, armpits, the navel and / or perianal region can also be affected. Psoriasis can take a widespread, involving large areas of skin. The appearance of the outbreaks depends on the type. Plaque psoriasis is the most common type of psoriasis, in which oval erythematous papules or plaques covered with dense silvery scales are formed.
Eruptions appear gradually, disappear and resume spontaneously or aftereffects of causative factors. There are subtypes and they are described in Table. 116-1. 5-30% of patients develop arthritis, which can lead to disability. Psoriasis is rarely life-threatening, but it can affect a patient's self-esteem. In addition to low self-esteem, constant care for the affected skin, clothing, bedding can adversely affect the quality of life.
What's bothering you?
How is psoriasis recognized?
The diagnosis of psoriasis is most often based on the appearance and localization of lesions. Psoriasis must be differentiated with seborrhoeic eczema, dermatophytosis, chronic lupus erythematosus, red lichen planus, pink lichen, basal cell carcinoma, Bowen's disease, simple chronic lichen and secondary syphilis. A biopsy is rarely needed and is not used for diagnosis. The severity of the disease (mild, moderate or severe) depends largely on the nature of the lesions and the ability of the patient to cope with the disease.
What do need to examine?
How to examine?
What tests are needed?
Who to contact?
Psoriasis: treatment
Given the pathogenesis of psoriasis, therapy should focus on correcting inflammation, hyperproliferation of epithelial cells and normalization of their differentiation. Currently, there are many methods and different drugs for the treatment of psoriasis. When appointing this or that method of treatment, one should approach each patient individually, taking into account the sex, age, profession, stage, clinical form, type of disease (summer, winter), prevalence of the process, concomitant and transferred diseases, previously received therapy.
Ordinary psoriasis is often treated by traditional conventional methods, which consist in the appointment of hyposensitizing (calcium chlorine, calcium gluconate, sodium thiosulfate), antihistamines (fenistil, taewegil, diazolin, analgesin, etc.), vitamin (PP, C, A and B) drugs , hepatoprotectors, agents that improve microcirculation, etc.