Psoriasis is a common chronic, relapsing, inflammatory skin disease that often severely disturbs patients’ normal lives.
Etiology and pathogenesis
The exact cause of psoriasis is still unclear. It is currently believed that psoriasis is a polygenic genetic disease in which genetic and environmental factors and other factors interact to finally cause proliferation of keratin-forming cells through a common immune-mediated pathway.
1, genetic factors: population surveys, family history, twins and HLA studies all support that psoriasis has a genetic predisposition and patients have a certain susceptibility. Domestic reports have a family history of 10% to 23.8%, and foreign literature reports a family history of about 30%; the disease has racial differences, and black people are rare; HLA is obviously related to psoriasis, of which the Cw6 locus is most obviously related to psoriasis; it is now internationally recognized that there are a variety of psoriasis susceptibility genes (PSORS1 to PSORS7, located in 1p, 1q, 3q, 4q, 6p, 17q and 19p, respectively). 6p, 17q and 19p).
2, environmental factors: the disease in identical twins in the same affected rate of 70%, suggesting that genetic factors alone is not enough to cause the onset of the disease. It is now generally believed that the occurrence of the disease is related to the following environmental factors.
(1) Infectious factors: Infection has been considered the main factor that promotes or aggravates psoriasis. 6% of patients have a history of throat infection, and up to 10%-20% of child patients have a history of acute tonsillitis or upper respiratory tract infection, the latter often has a better outcome when treated with antibiotics such as penicillin; it is also believed that the disease is caused by viral infection, and confirmed that there are eosinophilic inclusion bodies in the nucleus of spiny cells. Hellgren et al. found retrovirus-like particles in the urine and scale specimens of psoriasis patients, and the recurrence of psoriasis may also be the result of the transformation of the virus from latent state to active state, but further research is needed.
(2) Neuropsychiatric factors: 18.6% of patients’ morbidity is stimulated by neuropsychiatric factors, and studies have pointed out that neuropeptides (such as SP, CGRP, vasoactive intestinal peptide, etc.) are important mediators in psoriasis neurogenic inflammation, and it has been speculated that it may be a mediator of psycho-psychiatric factors affecting psoriasis.
(3) Trauma, certain physical and chemical factors, drug stimulation and climatic factors: all have a certain relationship with the onset of psoriasis patients, and a large domestic sample study shows that smoking and damp living environment are two of the most noteworthy factors.
3, immune factors: T-cell dermal infiltration is an important histopathological feature of the disease, indicating that the immune system is involved in the occurrence and development of the disease, and it is presumed that cytokines (IL-1, 6, 8, IFN-γ, etc.) released from activated T cells in the lesions stimulate the proliferation of keratin-forming cells, promoting and maintaining the course of psoriasis; more and more studies show that Langerhans cells play an important role in the development of psoriasis.
4, endocrine factors: mainly related to pregnancy, childbirth, lactation and menstruation, the onset of adult female patients with endocrine-related accounted for 10% to 20%; some patients in pregnancy to reduce the disease, the lesions recede, but there are also some in pregnancy or menstruation aggravated; early childhood incidence is low, may be related to the underdeveloped thymus gland in young children, but also thought to be related to parathyroid function.
Clinical presentation
According to a nationwide epidemiological survey in 1984, the incidence of psoriasis in China was 0.123%. The age of first occurrence is 15 to 45 years old, and the difference in prevalence between men and women is not significant. It can be clinically divided into four types: common type (accounting for more than 90%), pustular type, arthritic type, and erythrodermic type, and the latter three types are often transformed from the common type by inappropriate treatment; according to the course of the disease, it is divided into progressive, stable, and receding stages.
The disease is recurrent and no current treatment can prevent such recurrence. Most patients have one recurrence per year; 90% of patients have recurrence in winter and 10% in summer; a few patients can have only one recurrence and then no recurrence, but there seems to be no significant correlation with treatment.
Histopathology
Psoriasis vulgaris is hyperkeratotic, hyperkeratotic, and Munro micropustules with thinning or loss of the granular layer, thickening of the spinous layer, prolonged epidermal ridges with wider ends, the spinous layer at the top of the papillae showing significant intercellular edema, distorted dilated edema of the papillary vessels, and upward elongation of the papillary edema in a pestle shape with thinning of the spinous layer at its top; mild to moderate inflammatory cell infiltration in the upper dermis. In pustular psoriasis, spongy pustules (Kogoj micro-pustules) appear in the upper part of the spinous layer, and the inflammatory cell infiltration in the dermis is heavier; the rest of the changes are the same as in common psoriasis. Erythrodermic psoriasis has the pathological features of common psoriasis and chronic dermatitis.
Diagnosis and differential diagnosis
The disease is generally not difficult to diagnose based on the characteristics of typical lesions and recurrent occurrence; sometimes histopathological examination can provide important information.
The disease needs to be differentiated from the following diseases.
(1) seborrheic dermatitis: lesions with fine, greasy yellow scales, no punctate bleeding, lesions with indistinct boundaries, thinning and shedding of hair, hair not in bundles.
(2) Stage II syphilis rash: history of unclean sexual intercourse and hard chancre, palmoplantar keratotic desquamative papules; positive syphilis seropositivity.
(3) Parapsoriasis: light red sesame and green bean sized light red spots, thin scales, mild basal inflammation, no punctate hemorrhage, especially in the flexural side, generally does not occur in the head, face, palmoplantar and mucous membrane, can fade on its own, the onset is not seasonal.
(4) chronic simple moss: occurring in the side of the neck, extensor side of the limbs and lumbosacral, the lesions are mossy, no scaling, itching is intense.
(5)Pityriasis rosea: it occurs on the trunk and proximal extremities, and the long axis of lesions is consistent with the direction of skin lines.
(6) continuous extremity dermatitis: mostly with a history of finger (toe) trauma, clusters of pustules can form sub nail pus lake and creeping upward, can be generalized throughout the body.
(7) Herpes-like pustulosis: It occurs mostly in pregnant women, and is usually found in the groin, umbilicus, axilla, under the breast and other folds, and is a cluster of annular or polycyclic pustules with significant systemic symptoms.
(8) Erythrodermic disease: without a history of psoriasis, it starts with diffuse flushing and furfuraceous desquamation.
(9) Rheumatoid arthritis: mostly invades proximal small joints, symmetrical progressive aggravation; rheumatoid factor positive.
Treatment
Treatment of this disease can only achieve the immediate effect, there is no good prevention methods. In the treatment should be prohibited irritating topical drugs, should be done for different causes, types, disease period to give appropriate treatment, and should pay attention to psychological treatment.
1.Treatment with topical drugs
Glucocorticoid cream or ointment is effective, but should not be used for a long time, continuous large area, pay attention to its adverse reactions; vitamin A acid cream commonly used concentration of 0.025% to 0.1%, of which 0.05% to 0.01% tazarotene gel treatment plaque type psoriasis is more effective; vitamin D3 derivatives such as calcipotriol also has good efficacy, but should not be used for the face and skin folds; various keratin contributing (such as tar preparations, anthralin ointment, 10%-15% camptothecin ointment, salicylic acid ointment, etc.) can also be used topically.
2.Systemic treatment
Vitamin A acid drugs are suitable for all types of psoriasis and can be used as first-line drugs; immunosuppressants are mainly applied to erythrodermic, pustular and arthritic psoriasis; patients with obvious infection or generalized pustular psoriasis should use antibiotic drugs; glucocorticoids are only used for erythrodermic, arthritic or generalized pustular psoriasis with systemic symptoms, and should be applied for a short period of time and gradually reduced to prevent the condition from rebounding; Immunomodulators can be used for patients with low cellular immunity.
3.Physical therapy
Such as photochemotherapy (PUVA), phototherapy, bath therapy, etc., can be tried.
4.Other
Such as procaine closure therapy, peritoneal dialysis therapy, light quantum blood therapy and hyperbaric oxygen therapy, also have certain efficacy.
5.Chinese medicine
The treatment should be based on clinical manifestations, and the treatment should be based on clearing heat, cooling blood and activating blood to treat the blood-heat type, and nourishing blood and moistening skin, activating blood and dispersing wind to treat the blood-dry type. Commonly used herbs include Fu Ling, Ginseng, Radix Scutellariae, Radix Scutellariae, Radix Codonopsis, Rhizoma Atractylodis Macrocephalae, Radix et Rhizoma Ginseng, Radix Bupleuri, Centipede, Scorpion, Ocimum sanctum, Salviae Miltiorrhizae, Phellodendron, Dandelion, Radix Angelicae Sinensis and Zingiber officinale.