Psoriasis, commonly known as psoriasis, is a chronic inflammatory skin disease with a long course of the disease and a tendency to recur easily, and in some cases will not heal for almost a lifetime. The incidence of this disease is mainly young and middle-aged, and it has a greater impact on patients' physical health and mental status. The clinical manifestations are mainly erythema and scaly, which can be affected all over the body. The scalp and the extensor side of the limbs are more common, and most of them worsen in winter.
Although many studies have been conducted on the cause of this disease, it is still not very clear. It is currently believed that the occurrence of this disease is not a single cause, and may involve many aspects.
A considerable number of patients have a family history of the disease, and some families have obvious genetic predispositions. It is generally believed that people with a family history account for about 30%. The incidence rate varies greatly among different races. Psoriasis is a polygenic genetic disease in which genetic factors interact with environmental factors and other factors. The incidence of certain HLA antigens in patients with this disease is significantly increased. Psoriasis may overlap with other diseases (such as rheumatoid arthritis, atopic dermatitis, etc.).
Many scholars have confirmed that streptococcal infection is related to the onset and prolonged course of psoriasis from the aspects of humoral immunity (anti-streptococcal group), cellular immunity (peripheral blood and skin lesion T cells), bacterial culture, and treatment. In patients with psoriasis, Staphylococcus aureus infection can make skin lesions worse, which is related to the superantigen of Staphylococcus aureus exotoxin. Although the occurrence of this disease has a certain relationship with viruses (such as HIV) and fungus (such as Malassezia) infection, its exact mechanism has not been finally confirmed.
3. Immune abnormalities
A large number of studies have proved that psoriasis is an immune-mediated inflammatory skin disease, and its pathogenesis is related to the infiltration of inflammatory cells and inflammatory factors.
4. Endocrine factors
The skin lesions of some female patients are reduced or even disappeared after pregnancy and worsened after delivery.
Neuropsychiatric factors have a certain relationship with the onset of psoriasis. Drinking, smoking, drugs, and mental stress may induce psoriasis.
1. Psoriasis Vulgaris
It is the most common type, with multiple acute onsets. The typical manifestation is erythema with clear boundaries, different shapes and sizes, and inflammatory blush around it. Slight infiltration and thickening. The surface is covered with multiple silver-white scales. The scales are easy to scrape off, and the translucent film is light red and shiny after scraping, and small bleeding points (Auspitz sign) can be seen when the film is scratched. Skin lesions usually occur on the head, sacrum, and extensible sides of the extremities. Some patients feel itching to varying degrees.
2. Pustular psoriasis
Rarely, it is divided into the general hairstyle and palmoplantar type. Generalized pustular psoriasis is a cluster of superficial aseptic pustules that appear on the erythema, some of which can merge into a lake of pus. The disease can occur throughout the body. It is more common in the flexed side of the limbs and the folds, and the oral mucosa may be affected at the same time. Acute onset or sudden exacerbation is often accompanied by systemic symptoms such as chills, fever, joint pain, general malaise, and increased white blood cell count. The onset is mostly periodic, and psoriasis Vulgaris skin lesions often appear in the remission period. Palmoplantar pustulosis skin lesions are confined to the hands and feet, occur symmetrically, generally in good condition, stubborn, and recurrent
3. Erythrodermic psoriasis
Also known as psoriatic exfoliative dermatitis, it is a serious form of psoriasis. It is often caused by external use of strong irritating drugs, long-term large-scale use of glucocorticoids, rapid dose reduction, or sudden discontinuation of the drug. It manifests as diffuse flushing, swelling, and desquamation of the skin all over the body, accompanied by systemic symptoms such as fever, chills, and malaise, superficial lymph nodes swelling, and increased white blood cell count.
4. Psoriasis of joint disease
Also known as psoriatic arthritis. Patients with psoriasis also develop rheumatoid arthritis-like joint damage, which can affect the whole body, large and small joints, but the end digit (toe) joint disease is the most characteristic. The affected joints are swollen and painful, and the skin around the joints is often red and swollen. Joint symptoms often increase or decrease at the same time as skin symptoms. The blood rheumatoid factor is negative.
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