Psoriasis is a chronic, recurrent autoimmune-related skin disease characterized by erythematous scaly plaques, commonly found on the knees, elbows, and scalp. This condition affects approximately 2-3% of the global population and may be associated with complications such as psoriatic arthritis, significantly impacting patients' quality of life. Psoriasis has a cyclical course, alternating between flare-ups and remission, but currently, there is no cure. Long-term management is necessary to control symptoms.
The pathogenesis involves excessive proliferation of skin cells and abnormal activation of the immune system, leading to a markedly shortened skin regeneration cycle. Modern medicine has confirmed that the interaction between genetic predisposition and environmental triggers is key to disease onset, although the exact pathogenic mechanisms remain unclear. Treatment strategies have evolved to include topical medications, phototherapy, systemic drugs, and biologics, but personalized treatment plans are essential for optimal control.
Genetic studies show that specific polymorphisms in genes such as HLA-C are highly associated with psoriasis susceptibility, especially the HLA-C*06:02 genotype on chromosome 6, which increases risk. Family history is a significant risk factor; if a first-degree relative has psoriasis, the individual’s risk can exceed 50%. Genetic research indicates that about 40% of the disease risk can be attributed to heredity, but environmental triggers also play a crucial role.
Aberrant activation of T lymphocytes is central to psoriasis pathogenesis, particularly the overactivation of TH17 cells which release cytokines such as IL-17, inducing keratinocyte proliferation. This autoimmune response, coupled with skin barrier dysfunction, creates a vicious cycle leading to scale accumulation and erythema. Recent studies have identified abnormal activation of the IL-23/IL-17 signaling axis as a key driver of disease flare-ups.
The typical skin presentation includes well-defined erythematous plaques covered with silvery-white scales. Scratching may cause pinpoint bleeding (Auspitz sign). Common sites include extensor surfaces of elbows, knees, scalp, hips, and sacrum, with about 85% of patients having scalp involvement. Lesions can worsen rapidly due to stress, infections, or climate changes.
Approximately 30% of patients develop psoriatic arthritis, presenting as symmetric arthritis, dactylitis, and morning stiffness. Spinal involvement may resemble ankylosing spondylitis, with radiographic evidence of joint destruction. Systemic symptoms such as fatigue, low-grade fever, and weight loss may also occur.
Palmar-plantar psoriasis affects the palms and soles, often with painful nodules; inverse psoriasis occurs in skin folds, presenting as erythematous, moist lesions. Erythrodermic psoriasis is a severe form that can lead to systemic complications like sepsis, requiring immediate medical attention.
Diagnosis mainly relies on clinical features, with detailed history-taking and physical examination of skin lesions. Skin biopsy may be performed to exclude similar conditions such as eczema or fungal infections. Blood tests for rheumatoid factor and C-reactive protein, as well as imaging like X-ray or ultrasound, help assess joint damage.
Conditions to differentiate include seborrheic dermatitis, eczema, and drug-induced psoriasis. Seborrheic dermatitis typically occurs in oil-rich areas with thinner scales and greasy secretions. Drug-induced psoriasis may be associated with internal malignancies; blood tests are used to exclude malignancy. Severe forms must be distinguished from erythrodermic psoriasis, drug eruptions, or systemic lupus erythematosus skin manifestations.
First-line treatments include corticosteroid creams, retinoids, and coal tar preparations. Potent corticosteroids are suitable for extensor surfaces, while scalp lesions may require medicated shampoos containing coal tar. Newer topical agents like tacrolimus can inhibit T-cell activation and are suitable for sensitive areas such as the face.
Narrowband UVB phototherapy is commonly used for moderate cases, with dose adjustments based on lesion severity. PUVA therapy combines oral psoralen with UVA exposure and is effective for extensive lesions but carries a risk of photoaging. 308 nm pulsed dye laser can effectively target localized lesions, especially on the scalp or nails.
Moderate to severe cases may require oral methotrexate or cyclosporine, which suppress immune responses but require monitoring of liver and kidney function. Biologics such as anti-TNF-α monoclonal antibodies (e.g., adalimumab) can precisely block inflammatory signals, showing significant efficacy in treatment-resistant cases but with potential infection risks.
While complete prevention is not possible, the following measures can reduce the frequency of flare-ups:
Avoid trauma and scratching, wear loose clothing to reduce friction. Psychological support is vital; stress management courses or cognitive-behavioral therapy can lower flare-up frequency. Regular monitoring of liver, kidney, and cardiovascular health is recommended, as psoriasis patients have a 30% higher risk of cardiovascular disease.
Seek medical attention immediately if:
• Lesions cover more than 3% of body surface area
• Joint swelling or morning stiffness lasts over 1 hour
• Severe itching affects sleep quality
• Signs of skin infection such as pus or ulceration
• Treatment is ineffective or resistant to therapy
If systemic symptoms such as fever, weight loss, or lymphadenopathy occur, other systemic diseases should be considered. Regular follow-up every 3-6 months is advised, especially for patients on biologics, to monitor for potential infections.
Phototherapy works by using specific wavelengths of ultraviolet light (such as UVB or narrowband UVB) to suppress inflammation and reduce keratinocyte proliferation. Modern phototherapy devices can precisely control dosage. Short-term side effects may include skin redness and swelling, but long-term risks like skin cancer are minimized through professional supervision and dose adjustment.
Does diet modification help alleviate psoriasis symptoms?While diet cannot cure psoriasis directly, reducing high-sugar and high-fat foods can lower systemic inflammation. Omega-3-rich fish and antioxidant-rich fruits and vegetables may improve symptoms. It is recommended to work with a nutritionist to develop a personalized diet plan rather than self-imposing restrictive diets.
How does stress management help control psoriasis flare-ups?Stress can trigger or worsen psoriasis. Techniques such as mindfulness meditation, regular exercise, and cognitive-behavioral therapy can regulate stress hormones. Studies show that patients practicing stress management have an average 30% reduction in flare frequency. Long-term psychological strategies should be developed in consultation with healthcare providers.
What are the precautions for daily skin care?Avoid skincare products containing alcohol or harsh exfoliants to prevent skin barrier disruption. Keep water temperature below 40°C during bathing and limit washing time to 3 minutes. Immediately after bathing, apply fragrance-free, high-moisture creams to reduce scale buildup and itching.
How can psoriasis be distinguished from eczema on the skin?Psoriasis plaques typically have silvery-white scales, clear boundaries, and are often located on knees and elbows. Eczema presents as red, swollen, oozing, and chronic itching, commonly affecting the flexural areas of elbows and knees. If symptoms are unclear, skin biopsy or blood tests may be necessary for definitive diagnosis.
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