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 fixed-combination product containing calcipotriene and betamethasone dipropionate applied once daily for 4 weeks, which provides superior efficacy to either agent alone and maximizes patient adherence. 1, 2

Topical Therapy for Mild Disease (≤5% BSA)

First-Line Regimen: Body and Limbs

• Apply calcipotriene/betamethasone dipropionate gel or foam once daily for 4-12 weeks as the preferred initial approach, achieving clearance rates of 58-92% 1, 2, 3
• If using separate products, apply high-potency corticosteroid (clobetasol propionate 0.05% or betamethasone dipropionate 0.05%) in the morning and calcipotriene in the evening for maximum 2-4 weeks 1, 2, 4
• Limit potent corticosteroids to maximum 4 weeks of continuous use to prevent skin atrophy, then transition to maintenance regimen 4, 3

Maintenance Strategy After Initial Clearance

• Apply vitamin D analogue (calcipotriene) twice daily on weekdays combined with high-potency corticosteroid twice daily on weekends 1, 4
• This regimen can be continued for up to 52 weeks safely 1

Scalp Psoriasis

• Use calcipotriene/betamethasone dipropionate foam or gel for 4-12 weeks as first-line treatment 1
• Alternative: clobetasol propionate 0.05% shampoo twice weekly provides rapid symptom relief within 3-4 weeks 3

Face, Genitals, and Intertriginous Areas

• Apply low-potency corticosteroids or topical calcineurin inhibitors (tacrolimus 0.1%) to minimize atrophy risk 4, 3
• Calcipotriene combined with hydrocortisone for 8 weeks is effective for facial psoriasis 1
• Tacalcitol ointment is another option for facial involvement 1

Alternative Topical Agents

• Tazarotene 0.1% gel combined with moderate-to-high potency corticosteroids reduces irritation while maintaining efficacy; use for 8-12 weeks 1, 4
• Coal tar preparations have limited benefit and are no better than placebo in most studies 5, 6
• Avoid simultaneous use of salicylic acid with calcipotriene as the acidic pH inactivates calcipotriene 1, 3

Phototherapy for Moderate Disease (5-10% BSA or Inadequate Topical Response)

• Narrowband UVB phototherapy is first-line systemic treatment for patients failing optimized topical therapy after 8 weeks 2, 7
• PUVA (photochemotherapy) is the least toxic systemic agent; start at 70% of minimum phototoxic dose 2
• 308-nm excimer laser allows selective targeting of localized resistant areas including scalp and skin folds 2

Systemic Non-Biologic Therapy for Moderate-to-Severe Disease (>10% BSA)

Cyclosporine: Fastest Onset

• Dose: 3-5 mg/kg/day in two divided doses for rapid response (onset within 3 weeks) 1, 2
• Use as short-term "interventional therapy" for 3-4 month courses, not continuous long-term treatment 1, 2
• At 3 mg/kg/day, 36% achieve clear/almost clear at 8 weeks; at 5 mg/kg/day, 65% achieve this endpoint 1
• Mandatory monitoring: blood pressure and creatinine every 2 weeks for first 3 months, then monthly 1
• Contraindications: abnormal renal function, uncontrolled hypertension, malignancy 1, 3

Methotrexate: Standard Systemic Agent

• Response time: 2 weeks; FDA-approved since 1972 2
• Absolute contraindications: pregnancy, breastfeeding, wish to father children, significant hepatic damage, anemia, leukopenia, thrombocytopenia 3

Acitretin: For Pustular Variants

• Response time: 6 weeks; dose-dependent efficacy 1
• At 50 mg/day for 8 weeks, 23% achieve PASI 75; after 12 weeks, mean PASI improvement 70-75% 1
• Absolute contraindication: pregnancy or wish to conceive within 2 years of stopping treatment 3
• Particularly effective for pustular psoriasis with rapid, impressive responses 1, 3

Biologic Therapy for Severe Disease (>10% BSA with Significant Impact)

TNF-α Inhibitors

• Infliximab provides most rapid onset for severe disease including generalized pustular psoriasis: 5 mg/kg infused at weeks 0,2,6, then every 8 weeks 1, 2, 3, 8
• After 8-16 weeks, 50-70% of patients achieve PASI 75 with infliximab 1
• Adalimumab: 80 mg initial dose, then 40 mg every other week starting one week after initial dose 8
• Etanercept: 50 mg subcutaneously twice weekly for 12 weeks, then 50 mg once weekly 1

IL-17 and IL-23 Inhibitors

• Newer biologics (secukinumab, ixekizumab, guselkumab, risankizumab) show superior efficacy to TNF inhibitors but are reserved for patients with inadequate response to first-line biologics 7

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 improves outcomes 2
• Topical calcipotriene added to methotrexate enhances response 2

Critical Safety Monitoring for Topical Corticosteroids

• Implement mandatory clinical review every 4 weeks during active treatment with high-potency agents 1, 3
• No unsupervised repeat prescriptions for potent corticosteroids 1, 3
• Limit moderate-potency preparations to maximum 100g per month 1, 3
• Very potent (class 1-2) corticosteroids require dermatological supervision 4, 3

Medications That Precipitate or Worsen Psoriasis (AVOID)

• Never prescribe systemic corticosteroids for psoriasis—they cause severe, potentially fatal deterioration when discontinued, precipitating erythrodermic or generalized pustular psoriasis 1, 4, 3
• Lithium, chloroquine, mepacrine: 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 disease 1, 4, 3

Referral Criteria to Dermatology

• Body surface area >5% despite optimized topical therapy for 8 weeks 2, 3
• Erythrodermic or pustular psoriasis variants 3
• Need for systemic agents due to potential toxicity requiring specialist monitoring 1
• Psoriatic arthritis requiring biologic therapy 1, 8

Common Pitfall to Avoid

Perceived "tachyphylaxis" to topical corticosteroids is usually due to poor patient adherence rather than true receptor downregulation 4. Before escalating therapy, assess and optimize adherence with once-daily fixed-combination products rather than assuming treatment failure.