What are the guidelines for treating psoriasis?

Guidelines for Psoriasis Treatment

The cornerstone of psoriasis treatment is topical therapy for mild disease, phototherapy for moderate disease, and systemic/biologic agents for severe disease, with treatment selection based on disease severity, affected areas, and impact on quality of life. 1

Disease Classification and Treatment Selection

• Psoriasis severity is categorized as mild (typically <5% body surface area [BSA]) or moderate-to-severe (≥5% BSA or involvement of vulnerable areas) 1
• Assessment should include both patient perception of disability and objective assessment of extent and severity 2
• Symptomatic psoriasis (pain, bleeding, itching) should be considered for more aggressive therapy even if BSA involvement is limited 1

Treatment Algorithm Based on Disease Severity

Mild Psoriasis (First-Line Topical Therapies)

• Topical corticosteroids are the cornerstone of treatment for most patients with psoriasis, particularly those with limited disease 2

• Efficacy rates of different classes of topical corticosteroids vary widely (41-92%), with higher potency generally correlating with greater efficacy 2

• Guidelines for topical corticosteroid use include:

  • Regular clinical review
  • No unsupervised repeat prescriptions
  • No more than 100g of a moderately potent preparation monthly
  • Periods of alternative treatment each year
  • Potent/very potent preparations should be under dermatological supervision 2

• Vitamin D analogs (calcipotriene) are effective first-line agents that can be used alone or in combination with corticosteroids 1, 3

• Coal tar is extremely safe and can be used either as refined products or cruder extracts, starting with concentrations of 0.5-1.0% and increasing to a maximum of 10% 2

• Dithranol (anthralin) requires explanation of side effects such as irritancy and staining, starting at 0.1-0.25% concentration 2

Combination Topical Therapy

• Combination of topical corticosteroids with vitamin D analogs enhances efficacy and reduces side effects 3
• Vitamin D analogs counter epidermal dysregulation while corticosteroids act as immunosuppressors, providing complementary mechanisms of action 3
• Multiple topical agents can be used concurrently to take advantage of varied mechanisms of action, but be aware of compatibility issues 2

Moderate-to-Severe Psoriasis

• Phototherapy is recommended as first-line treatment for moderate-to-severe psoriasis, including narrowband UVB and PUVA 1, 4

• Traditional systemic agents (second-line) include:

  • Methotrexate (15 mg weekly initially, maximum 25-30 mg weekly) 5
  • Cyclosporine (2.5-5 mg/kg daily) 5
  • Acitretin (25-50 mg daily, particularly effective for pustular psoriasis) 5

• Biologic agents (third-line) include TNF inhibitors, IL-17 inhibitors, IL-23 inhibitors, and IL-12/23 inhibitors 1

• For plaque psoriasis, adalimumab (Humira) is administered as 80 mg initial dose, followed by 40 mg every other week starting one week after initial dose 6

Special Considerations for Specific Psoriasis Types

• For scalp psoriasis: calcipotriene foam or calcipotriene plus betamethasone dipropionate gel for 4-12 weeks 1
• For facial and intertriginous psoriasis: low-potency corticosteroids to avoid skin atrophy 1, 7
• For psoriatic arthritis: NSAIDs for mild joint symptoms, DMARDs for moderate-to-severe joint involvement, and TNF inhibitors for inadequate DMARD response 1, 6

Treatment Strategies and Monitoring

• Short contact therapy with dithranol (15-45 minutes every 24 hours) can be beneficial 2
• Rotational therapy (switching between treatment modalities every 1-2 years) may minimize cumulative toxicity 1
• For resistant lesions, trying alternative topical agents before considering more aggressive management is recommended 2
• Topical agents can be combined with phototherapy or systemic agents for enhanced efficacy in patients with areas of active disease 2, 8

Common Pitfalls and Caveats

• Drugs that may precipitate or worsen psoriasis include alcohol, beta-blockers, NSAIDs, lithium, chloroquine, and mepacrine 2
• Systemic corticosteroids should be avoided as they can cause disease flare during taper 1
• Long-term use of potent topical corticosteroids can cause skin atrophy, striae, and telangiectasia 1, 7
• Vitamin D analogs should be applied after phototherapy to avoid inactivation 1
• Combination of multiple systemic agents may increase risk of toxicity 4
• Great care should be taken with dithranol on sensitive body sites such as the face, flexures, and genitalia 2