What are the treatment options for a patient with chronic plaque psoriasis?

Treatment of Chronic Plaque Psoriasis

For mild psoriasis (≤5% body surface area), initiate treatment with a high-potency topical corticosteroid combined with calcipotriene (vitamin D analogue), which achieves clearance rates of 58-92% and provides superior efficacy compared to either agent alone. 1, 2, 3

Initial Treatment Algorithm for Body Psoriasis

Mild Disease (≤5% BSA)

• Apply clobetasol propionate 0.05% or betamethasone dipropionate 0.05% twice daily for a maximum of 2-4 weeks 2, 4, 3
• Combine with calcipotriene using either:
  • Fixed-combination products (calcipotriene/betamethasone dipropionate gel or foam) once daily for 4-12 weeks 1, 4, 5
  • Separate products: high-potency corticosteroid in morning and vitamin D analogue in evening 1, 4
  • Weekday/weekend regimen: vitamin D analogues twice daily on weekdays with high-potency corticosteroids twice daily on weekends for maintenance 1

Moderate-to-Severe Disease (>5% BSA)

• Escalate to systemic therapy when body surface area exceeds 5%, after inadequate response to optimized topical therapy for 8 weeks, or if erythrodermic/pustular psoriasis develops 3
• First-line systemic option: Photochemotherapy (PUVA) at 70% of minimum phototoxic dose, as it represents the least toxic systemic agent 2, 3
• Alternative systemic agents:
  • Cyclosporine 3-5 mg/kg/day for rapid response (3 weeks), used in short 3-4 month courses 1, 2, 3
  • Methotrexate with 2-week response time 1, 2
  • Acitretin with 6-week response time 1, 3

Site-Specific Treatment Modifications

Scalp Psoriasis

• Use calcipotriene foam or calcipotriene plus betamethasone dipropionate gel for 4-12 weeks 1
• Clobetasol propionate 0.05% shampoo twice weekly provides rapid symptom relief within 3-4 weeks 3
• Topical corticosteroids (class 1-7) for at least 4 weeks 4

Face, Genitals, and Intertriginous Areas

• Apply low-potency corticosteroids or topical calcineurin inhibitors (tacrolimus 0.1%) to minimize atrophy risk 4, 3
• Topical tacalcitol ointment or calcipotriene combined with hydrocortisone for 8 weeks can be used for facial psoriasis 1

Nail Psoriasis

• Topical vitamin D analogues combined with betamethasone dipropionate reduces nail thickness, hyperkeratosis, onycholysis, and pain 1
• Tazarotene 0.1% cream under occlusion for 12 weeks is comparable to clobetasol 0.05% cream 1

Biologic Therapy for Severe Disease

For generalized pustular psoriasis or severe disease requiring rapid response, infliximab demonstrates rapid and often complete disease clearance and should be considered first-line biologic therapy. 1, 2, 3

• Infliximab dosing: 5 mg/kg infused at weeks 0,2, and 6, then every 8 weeks thereafter 1, 2, 3
• Adalimumab: 80 mg initial dose, followed by 40 mg every other week starting one week after initial dose 6
• Adalimumab is effective for both skin and joint symptoms in psoriatic arthritis 2

Combination Strategies to Enhance Efficacy

• Adding ultrahigh-potency topical corticosteroid to standard dose etanercept for 12 weeks accelerates clearance 2
• Calcipotriene/betamethasone added to standard dose adalimumab for 16 weeks accelerates clearance of psoriatic plaques 2
• Topical calcipotriene added to standard dose methotrexate improves outcomes 2

Critical Safety Monitoring and Precautions

Topical Corticosteroid Safety

• Implement mandatory clinical review every 4 weeks during active treatment with no unsupervised repeat prescriptions for high-potency agents 1, 4, 3
• Limit moderate-potency corticosteroid use to maximum 100g per month 1, 4, 3
• Require dermatological supervision for class 1-2 (very potent) preparations 1, 4, 3
• Plan annual periods where an alternative treatment is used to minimize long-term corticosteroid exposure 4

Systemic Therapy Monitoring

• Cyclosporine: Monitor blood pressure, BUN, and creatinine every other week during initial 3 months, then monthly 1
• Methotrexate: Absolute contraindications include pregnancy, breastfeeding, wish to father children, significant hepatic damage, anemia, leucopenia, thrombocytopenia 3
• Acitretin: Requires contraception with absolute contraindication for pregnancy or wish to conceive within 2 years of stopping treatment 3

Medications That Must Be Avoided

Never prescribe systemic corticosteroids for psoriasis, as they can precipitate erythrodermic psoriasis, generalized pustular psoriasis, or very unstable psoriasis when discontinued, potentially causing severe or fatal deterioration. 1, 4, 3

• Lithium, chloroquine, and mepacrine are associated with severe, potentially fatal psoriasis deterioration 1, 4, 3
• Beta-blockers and NSAIDs may worsen psoriasis in some patients 1, 4, 3
• Alcohol can precipitate or worsen psoriasis 1, 4, 3
• Avoid simultaneous use of salicylic acid with calcipotriene, as the acidic pH inactivates calcipotriene and reduces effectiveness 1, 4, 3

Alternative and Adjunctive Therapies

• Tazarotene 0.1% gel for 8-12 weeks is recommended for mild-to-moderate psoriasis, best combined with moderate-to-high potency corticosteroids to reduce irritation 1, 4
• Oral curcumin supplementation may benefit patients with psoriasis of varying severity as adjunctive therapy 1, 2
• Aloe vera applied thrice daily for 4 weeks may be efficacious for mild psoriasis in patients not allergic to it 1
• Oral fish oil/omega-3 fatty acid supplementation may augment the effects of topical, oral-systemic, and phototherapy 1

Common Pitfalls to Avoid

• Perceived "tachyphylaxis" to topical corticosteroids is often due to poor patient adherence rather than receptor down-regulation 4
• Coal tar and retinoids (as monotherapy) are no better than placebo for trunk and limb psoriasis 7
• Vitamin D analogues are significantly less effective than potent or very potent corticosteroids for scalp psoriasis 8, 9
• Most patients with chronic stable plaque psoriasis can be managed by general practitioners, but those requiring systemic agents should be under dermatologist supervision due to potential toxicity 1, 4