Psoriasis Overview and Management

Psoriasis Overview

• Psoriasis is a chronic, proliferative skin disease.
• Plaque psoriasis is the most common type.
• Characterized by well-defined, thickened red skin patches covered with silvery scales.
• Genetics and environmental factors contribute to development and exacerbation.
• Bimodal age distribution, with peaks between ages 18-39 and 50-69.

Pathogenesis

• Psoriatic plaques are marked by epidermal hyperplasia, leukocyte infiltration, and changes in dermal microvasculature.
• Immune-mediated response systems are disrupted, leading to increased keratinocyte proliferation.

Prognosis & Treatment

• Psoriasis negatively impacts quality of life (social, psychological, physical).
• No known cure; it is a treatable condition.
• Shared decision-making is important in treatment selection due to potential side effects.
• Treatment aims for complete clearing of lesions or satisfactory improvement for the patient.

Risk Factors

• Hot weather, sunlight, and humidity can help clear psoriasis, while cold weather is detrimental.
• Anxiety and psychological stress negatively affect the disease course.
• Viral and bacterial infections can trigger psoriasis onset or flare-ups.
• Trauma to the skin (e.g., cuts, burns) can initiate lesion development.

Types of Psoriasis

• Plaque psoriasis: Characterized by sharply demarcated, red, scaly patches; commonly affects elbows, knees, scalp, and trunk.
• Erythrodermic psoriasis: The most severe form; involves intense redness and scaling over >90% of the body surface area.
• Pustular psoriasis: Localized to palms and soles, with a generalized version possible.
• Guttate psoriasis: Small, fine, red scales; often follows strep throat; usually found on the trunk, arms, and legs.

Psoriatic Arthritis

• Psoriatic arthritis is a form of seronegative inflammatory arthritis.
• Affects approximately 25% of psoriasis patients.

Drug-Induced Psoriasis

• Several medications, including antibiotics (e.g., penicillins, sulfonamides), corticosteroids (post-withdrawal), antimalarial agents, and others are linked to psoriasis onset or flare-up.

Classification of Psoriasis

• Psoriasis Area and Severity Index (PASI) is a validated scoring index used in clinical trials to quantify disease severity and extent.
• Severity classification helps guide treatment selection.
  • Mild disease: affects limited areas (excluding face, genitals, hands, and feet) and may respond to topical therapies alone.
  • Moderate disease: might require phototherapy or non-biological systemic agents
  • Severe disease: needs escalation to biologic therapies

Non-Pharmacologic Modalities

• Psoriasis can be emotionally and psychologically challenging for patients.
• It may affect participation in sports/outdoor activities and lead to lifestyle changes.
• Psychological support is crucial to coping and adherence to treatment plans.

Treatment of Mild-Moderate Psoriasis

• Topical therapies are the first-line treatments for mild psoriasis.
• Treatment considerations include disease severity, cost, and convenience.
• Non-pharmacologic therapies like spa therapy or support groups augment treatment plans.

Topical Agents for Psoriasis

• Emollients: basic adjuvants; safe, inexpensive; reduce scaling, itching, and discomfort, but provide minimal relief alone.
• Keratolytics (salicylic acid, urea): reduce hyperkeratosis and help other topical treatments penetrate better but may cause side effects when used extensively.

Additional Topical Treatments

• Topical Corticosteroids: Provide rapid response and control inflammation and itching. Particularly helpful for intertriginous areas and face, with moderate efficacy for psoriasis.
• Coal Tar: Particularly effective for flaky scalp lesions, enhancing psoriasis clearance with UVB treatment; with limited side effects.

Additional Systemic Treatments

• Vitamin D Analogs: Slow onset, expensive, and can impact bone metabolism; used in maintenance therapy.
• UVB: Effective in treating moderate-to-severe psoriasis, eliminating problems often arising with topical corticosteroids; can cause sunburn.

Treatment for Moderate-to-Severe Psoriasis

• Systemic medications like methotrexate, cyclosporine, and immunomodulators are used if milder therapies are ineffective.
• Immunomodulators (etanercept, infliximab, adalimumab, etc.): a targeted therapy; effective for moderate-to-severe cases; maintain remission; expensive and parenteral; with a risk of infections.

Phototherapy

• Phototherapy (using UV light) has a long history in treating psoriasis.
• It may be considered for moderate to severe cases or if topical therapies are insufficient. It can be helpful for mild, refractory cases.
• Important to assess for skin cancer risk and use appropriate photo-protection considerations.
• Treatment dosing is titrated up over time, and may need to be restarted at lower doses if doses are missed.