What are the treatment options for psoriasis?

Psoriasis Treatment

For mild psoriasis (<5% body surface area), start with combination topical therapy using calcipotriene/betamethasone dipropionate once daily for 4-8 weeks, which achieves clear or almost clear status in 48-74% of patients. 1

Disease Severity Classification

• Mild psoriasis is defined as <5% body surface area (BSA) involvement in asymptomatic patients who are candidates for topical therapy alone 1, 2
• Moderate-to-severe psoriasis is defined as ≥5% BSA or involvement of vulnerable areas (face, genitals, hands, feet) 1, 3
• Symptomatic psoriasis (pain, bleeding, itching) warrants systemic or phototherapy consideration regardless of BSA involvement 1, 3, 2
• Quality of life impact should drive treatment escalation even when physical extent is limited 1, 3

Treatment Algorithm by Severity

Mild Psoriasis: Topical Therapy

First-Line Topical Approach:

• Calcipotriene/betamethasone dipropionate combination product once daily for 4-8 weeks is the most effective first-line therapy 1, 2
• For body/extremities, use class 2-5 (moderate to high potency) corticosteroids initially 2
• For thick, chronic plaques, use class 1 ultrahigh-potency corticosteroids (clobetasol propionate 0.05% or halobetasol propionate 0.05%) 1, 2
• Maximum continuous high-potency corticosteroid use: 4 weeks 2

Site-Specific Modifications:

• Scalp psoriasis: Calcipotriene foam or calcipotriene plus betamethasone dipropionate gel for 4-12 weeks 1, 3, 2
• Facial/intertriginous psoriasis: Low-potency corticosteroids or calcitriol ointment to avoid skin atrophy 1, 3, 2
• Nail psoriasis: Calcipotriene combined with betamethasone dipropionate, though efficacy is limited due to poor nail matrix penetration 2

Maintenance Strategy After Initial Control:

• Transition to weekend-only high-potency corticosteroid application (twice daily on weekends) with weekday vitamin D analogue therapy (twice daily on weekdays) to minimize corticosteroid exposure while maintaining efficacy 1, 2
• Maximum vitamin D analogue use: 100g per week to avoid hypercalcemia 1, 2

Moderate-to-Severe Psoriasis: Phototherapy and Systemic Agents

First-Line for Moderate-to-Severe Disease:

• Narrowband UVB or PUVA phototherapy 1, 3
• The 308-nm excimer laser allows selective targeting of localized resistant areas such as scalp and skin folds 2

Second-Line Traditional Systemic Agents:

• Methotrexate (FDA-approved since 1972, competitive inhibitor of dihydrofolate reductase) requires regular monitoring of full blood count, liver function tests, and serum creatinine 1, 2
• Cyclosporine 3-5 mg/kg/day for rapid onset of action, particularly effective for erythrodermic psoriasis; use in short 3-4 month "interventional" courses; requires monitoring of blood pressure, renal function, and lipid profile 1, 2
• Acitretin decreases keratinocyte hyperproliferation and restores normal epidermal differentiation, but is absolutely contraindicated in women of childbearing potential due to teratogenicity 1, 2

Third-Line Biologic Agents:

• IL-17 inhibitors, IL-23 inhibitors, IL-12/23 inhibitors, and TNF inhibitors are recommended for severe disease or inadequate response to traditional systemic agents 1, 3
• Adalimumab dosing for psoriasis: 80 mg initial dose, followed by 40 mg every other week starting one week after initial dose 4

Combination Therapy Strategies

Topical Combinations:

• Combining tazarotene with medium- or high-potency corticosteroids for 8-16 weeks increases efficacy while reducing local adverse events and prolonging remission 1
• Emollients (water-in-oil cream or lotion) can be used as corticosteroid-sparing agents when combined with betamethasone dipropionate 2

Biologic + Topical Combinations:

• Adding ultrahigh-potency (class 1) topical corticosteroid to standard dose etanercept for 12 weeks is recommended with Level I evidence 1, 2
• Adding calcipotriene/betamethasone to standard dose adalimumab for 16 weeks accelerates clearance of psoriatic plaques 1, 2
• Adding topical calcipotriene to standard dose methotrexate therapy is recommended with Level I evidence 1, 2
• All topical corticosteroids can be used in combination with any biologics 1, 2

Psoriatic Arthritis Management

• Mild joint symptoms: NSAIDs 1, 3
• Moderate-to-severe joint involvement: DMARDs (methotrexate, sulfasalazine, leflunomide) 1, 3
• Inadequate response to at least one DMARD: TNF inhibitors 1, 3
• Severe enthesitis failing other therapies: Consider TNF inhibitor 1
• Adalimumab is effective for both skin and joint symptoms in psoriatic arthritis 3

Critical Pitfalls to Avoid

• Never use systemic corticosteroids in psoriasis—they cause disease flare during taper 1, 3, 2
• Never combine salicylic acid with calcipotriene simultaneously—the acidic pH inactivates calcipotriene and eliminates its effectiveness 1
• Long-term use of potent topical corticosteroids causes skin atrophy, striae, and telangiectasia 1, 3
• Do not use high-potency corticosteroids on face or flexures—use low-potency agents instead 1
• Apply vitamin D analogues after phototherapy to avoid inactivation 3, 2
• All commonly used systemic agents are absolutely contraindicated in pregnancy 1
• Commercial sunbeds are rarely effective for psoriasis and may cause premature skin aging and increased skin fragility 1
• Long-term use of high-potency corticosteroids beyond 12 weeks requires careful physician supervision 2

Monitoring Requirements

• Methotrexate: Regular monitoring of full blood count, liver function tests, and serum creatinine 1
• Cyclosporine: Regular monitoring of blood pressure, renal function, and lipid profile 1
• Before starting biologics: Perform test for latent TB; if positive, start treatment for TB prior to starting therapy 4
• Monitor all patients for active TB during biologic treatment, even if initial latent TB test is negative 4

Rotational Therapy Consideration

• Rotational therapy (switching between treatment modalities every 1-2 years) may minimize cumulative toxicity of individual treatments 3