Psoriasis is a common chronic inflammatory skin disease. It is a polygenic disease that can be triggered by a variety of triggering factors, such as trauma, infection, and medications that may induce the disease in susceptible individuals. The typical skin manifestation is a well-defined red plaque with silvery-white scales. In mild cases, the patches may appear as a few silver coin-sized patches on the elbows and knees, or in severe cases, the whole body may be involved. The pathophysiological mechanisms are mainly abnormalities in epidermal proliferation and differentiation and activation of the immune system.
Predisposing factors.
1, infection.
Especially bacterial infections can trigger or aggravate psoriasis. 45% of psoriasis patients can be found with triggering infections. Streptococcal infections, especially pharyngitis, are the most common triggers. Streptococci can be isolated from periodontal abscesses, perianal cellulitis, and impetigo.
Streptococcal infections can cause the onset of pitting psoriasis, especially in children and adolescents. It can also cause pustular psoriasis or aggravate plaque psoriasis. Sometimes, sinus, respiratory, gastrointestinal and genitourinary infections can also cause exacerbation of psoriasis. HIV infection can also aggravate psoriasis.
2. Endocrine.
Low blood calcium is a causative factor in pustular psoriasis with pancytopenia. Although vitamin D3 derivatives can improve psoriasis, vitamin D3 deficiency does not cause psoriasis. 50% of pregnant patients with psoriasis will improve. However, some pregnant patients develop eruptive pustulosis (it is thought that this is also a form of pustular psoriasis).
3. Neuropsychiatric stress.
The relationship between mental stress and psoriasis has been very clear, it can both induce the onset of psoriasis and aggravate the existing psoriasis. Aggravation often occurs within a few weeks to a few months after mental stimulation.
4. Drugs.
Lithium preparations, interferons, beta-blockers and antimalarials can aggravate psoriasis. Rapid reduction of hormones can cause psoriasis to flare up or lead to pustular psoriasis.
5. Alcohol consumption, smoking and obesity.
Obesity, excessive alcohol consumption and smoking have all been reported to be associated with psoriasis. However, some studies have shown that obesity and excessive alcohol consumption may also be a result of psoriasis.
It has also been found that exposure to moisture is also a factor in the development of psoriasis, and further research is needed to determine whether eating fish and shrimp is a triggering factor for psoriasis.
According to the different clinical manifestations, psoriasis is divided into four types.
Psoriasis vulgaris
It is the most common type in clinical practice. The lesions are initially red papules or macules, the size of corn to green beans, and later can gradually expand and fuse into red patches with clear boundaries and obvious basal infiltration, and the surface of the lesions is covered with multiple layers of silvery white scales, which can be easily scraped off. When the surface scales are removed, a layer of light red shiny film can be seen, and when the film is scraped away, small sieve-like bleeding dots appear, which is called “punctate bleeding phenomenon”. White scales, shiny film and punctate bleeding are the clinical features of this disease.
Pustular psoriasis
It is less common clinically and accounts for about 0.77% of patients with psoriasis. It can generally be divided into 2 types: generalized pustular type and palmoplantar pustular type.
Generalized pustular type
The onset of the disease is often triggered by factors such as inappropriate treatment, stimulation by topical drugs or too rapid withdrawal of hormones. With acute onset, small yellow superficial pustules appear on or around the basic damage of psoriasis vulgaris, mostly on the flexors and folds of the extremities. In severe cases, dense pustules may appear all over the body, and the pustules may fuse into pus lakes, and the skin may become red and swollen.
Palmoplantar pustular type
The lesions are only seen on the palmoplantar area, and dense corn-sized pustules appear on the basis of erythema, the walls of the pustules are not easy to rupture, and the pustules dry up and crust and peel off in about 2 weeks. The pustules often recur, and the lesions may gradually spread to the dorsal side of the palms and toes.
Psoriasis arthritis
In addition to psoriasis damage, rheumatoid arthritis symptoms may occur in patients, with an incidence of about 6.8%. The joint symptoms are aggravated or reduced simultaneously with the skin symptoms. Most cases are often secondary to psoriasis or coexist with pustular psoriasis or erythrodermic psoriasis.
The lesions can affect large and small joints, but small joints such as the hands, wrists and feet, especially the finger-plantar end joints, are the most common. These joints are red, swollen and painful, with stiffness and even muscle atrophy. Some cases may have rheumatoid arthritis changes on X-ray, but rheumatoid factor tests are negative.
Erythrodermic psoriasis
Also known as psoriatic exfoliative dermatitis, it accounts for about 1% of psoriasis patients. It is clinically severe and is most often caused by the stimulation of topical medication or inappropriate treatment during the progressive phase of psoriasis vulgaris. The clinical manifestation is exfoliative dermatitis, mostly seen as diffuse skin flushing, swelling, large amount of bran-like flaking, palm and toe keratinization, nail thickening or even loss. At this time, the features of common psoriasis often disappear, but small patches of common psoriasis lesions can be seen after healing. Patients are often accompanied by fever, chills, headache and other symptoms, and the superficial lymph nodes of the whole body are enlarged.
Disease treatment.
Local treatment
1.Glucocorticoid
Topical glucocorticosteroids are reliable in the treatment of mild to moderate psoriasis, and their combination with salicylic acid can improve the efficacy, and their combination with other systemic or local therapeutic drugs can also improve the clearance rate of skin lesions. The most commonly used combination therapy is with topical vitamin D3 derivatives.
2.Calcium-modulated neurophosphatase inhibitors
Calcium-regulated neurophosphatase inhibitors are effective in treating hormone-sensitive skin areas, such as the face, folds of friction, and the anogenital area. Therefore, topical pimecrolimus and tacrolimus can be used as a reasonable supplement to the treatment of psoriasis in special areas.
3.Tazarotene
Tazarotene can be used in combination with topical glucocorticoids to obtain better efficacy and reduce skin irritation without serious adverse drug reactions, but contact with normal skin should be avoided to prevent skin irritation. Topical tazarotene is recommended for the treatment of mild to moderate psoriasis.
4.Phototherapy
Phototherapy is a safe and effective treatment for moderate to severe psoriasis, and clinical effects can be produced within 2 weeks of treatment. UV erythema from overexposure is a common side effect, and repeated or long-term application may lead to premature skin aging, etc., while the risk of tumorigenesis may be associated with oral PUVA therapy or topical PUVA and UVB therapy.
Phototherapy is recommended for the induction treatment of moderate and severe psoriasis, especially for those with extensive lesions, and the newly introduced narrow-spectrum medium-wave UV therapy instrument in our department has achieved good efficacy in the treatment of psoriasis.