Psoriasis

Disease Description (Causes and Symptoms)

• Definition: A chronic, recurrent inflammatory skin disease characterized by well-demarcated erythematous papules and plaques covered with silvery-white scales. Histologically, excessive proliferation of keratinocytes and epidermal thickening are observed.
• Causes and pathophysiology: Genetic predisposition + environmental triggers (skin trauma [Koebner phenomenon], infections—particularly streptococcal infections, cold and dry climates, medications, stress, etc.) stimulate the immune system (particularly T cells and the cytokine axis: TNF-α, IL-17, IL-23, etc.), causing keratinocyte hyperproliferation and inflammation.
• Main symptoms
  • Silvery-white scales over well-demarcated erythematous plaques (plaque psoriasis)
  • Pinpoint bleeding when scales are removed (Auspitz sign)
  • Mainly affects the elbows, knees, shins (extensor surfaces of the limbs), scalp, and sacral area
  • Hand and toenail lesions (approximately 30–50%): nail pitting, onycholysis, thickening, discoloration, etc.
  • Variants: guttate psoriasis (small numbers of papules), pustular psoriasis, inverse psoriasis (skin folds), erythrodermic psoriasis (generalized), etc.

Treatment Methods (Standard Treatment·Medications·Procedures·Lifestyle Management·Precautions)

• Topical treatment (mainly for mild cases)
  • Topical corticosteroids (short-term use recommended according to potency), vitamin D analogues (calcipotriol), moisturizers, salicylic acid (descaling)
  • Mild formulations or nonsteroidal agents are recommended for the face and skin folds
  • Precaution: Long-term use of high-potency steroids may cause side effects such as skin atrophy and telangiectasia
• Phototherapy
  • Narrowband UVB (narrowband UVB): Can also be used in children and pregnant women and is currently widely used
  • PUVA (psoralen + UVA): Effective, but use is limited because of oral medication side effects, photosensitivity, and the possibility of an increased long-term risk of skin cancer
  • Excimer laser: Targeted high-intensity irradiation (used as an adjunctive treatment for small groups of lesions)
  • Precaution: Excessive irradiation may cause burns; long-term skin cancer risk should be considered
• Systemic treatment (moderate to severe)
  • Conventional medications: Methotrexate (hepatotoxicity; blood test monitoring required), Cyclosporine (effects on the kidneys and blood pressure), Acitretin (oral retinoid, teratogenic)
  • Immunomodulator: Steroid (short-term use recommended)
  • Targeted and biologic agents (severe/refractory cases)
    • TNF-α inhibitors: etanercept, infliximab, adalimumab
    • IL-12/23 inhibitor: ustekinumab
    • IL-17 inhibitors: secukinumab, ixekizumab
    • IL-23 inhibitors: guselkumab, risankizumab, etc.
  • Oral small molecule: apremilast (PDE4 inhibitor)
  • Precautions and monitoring: Test for tuberculosis and hepatitis B before administering biologic agents, regularly monitor for infections, confirm vaccination history, and select medications appropriately when planning pregnancy (e.g., acitretin is contraindicated during pregnancy)
• Lifestyle management and prevention
  • Moisturize thoroughly and avoid physical damage such as skin friction and excessive scrubbing (to prevent the Koebner phenomenon)
  • Manage infections (e.g., throat infections), manage stress, stop smoking and excessive alcohol consumption, and lose weight (obesity is an aggravating factor)
• Complications requiring attention
  • Psoriatic arthritis (rheumatoid-like joint symptoms), increased risk of metabolic syndrome and cardiovascular disease, psychological effects (depression and reduced social functioning), treatment-related infections and medication side effects

Checklist Before an Outpatient Visit (Including Preparation Items, Points to Review, and Sample Questions)

• Items and records to prepare
  • List of all medications and supplements currently being taken (including dosage and frequency)
  • Records of previous dermatology prescriptions and treatments (topical medications, phototherapy, systemic treatment, biologic agents), including their effects and side effects
  • Recent photographs (by lesion location), when symptoms began or worsened, and triggering circumstances (infection, trauma, medication, stress, seasonal changes)
  • Underlying conditions (liver, kidney, and cardiovascular disease, history of infections), pregnancy status, or pregnancy plans
  • Recent test results, if available (liver function, kidney function, CBC, viral tests, etc.)
• Information to tell the doctor in advance during the outpatient visit
  • Any ointments or alternative therapies currently being used for self-treatment or without a prescription
  • Vaccination history (especially whether any live vaccines have been used)
  • Previous use of biologic agents and reasons for discontinuation

Examples of General Questions to Ask the Doctor

• What are the expected effects and side effects of this medication (or treatment)?
• What is the severity of my disease and its prognosis (impact on daily life)?
• I am planning a pregnancy or breastfeeding. Which treatments are safe?
• When will the treatment effect be evaluated, and what are the alternative options if it is ineffective?
• What tests and monitoring intervals are required when using systemic treatment or biologic agents?

Examples of Disease-Specific Questions

• I have hand and toenail lesions. What treatment is needed to prevent permanent damage (permanent deformity) caused by them?
• I also have joint pain (or morning stiffness). What tests should I undergo to determine whether I have psoriatic arthritis?