What are the treatment options for psoriasis?

Treatment of Psoriasis

For mild psoriasis (<5% body surface area), start with calcipotriene/betamethasone dipropionate combination product once daily for 4-8 weeks, which achieves clear or almost clear status in 48-74% of patients. 1, 2

Disease Severity Classification and Treatment Selection

Mild psoriasis is defined as <5% body surface area (BSA) involvement with minimal symptoms, while moderate-to-severe disease includes ≥5% BSA, symptomatic disease (pain, bleeding, itching), or significant quality of life impact. 1, 3 Importantly, even patients with limited BSA should be considered for systemic or phototherapy if they have symptoms or quality of life impairment. 1, 2

First-Line Topical Therapy for Mild Disease

Standard Body Sites (Trunk and Extremities)

• Apply calcipotriene/betamethasone dipropionate combination product once daily for 4-8 weeks as the most effective first-line approach. 1, 2
• Alternatively, use high-potency corticosteroids such as clobetasol propionate 0.05% or halobetasol propionate 0.05% twice daily. 1, 2, 4
• Maximum vitamin D analogue use is 100g per week to avoid hypercalcemia. 5, 1, 2

Maintenance Strategy After Initial Control

Transition to weekend-only high-potency corticosteroid application (twice daily on weekends) combined with weekday vitamin D analogue therapy (twice daily on weekdays) to minimize corticosteroid exposure while maintaining efficacy. 1 This corticosteroid-sparing approach reduces the risk of cutaneous atrophy, striae, and telangiectasia. 5, 1

Site-Specific Modifications

For facial and intertriginous psoriasis:

• Use low-potency corticosteroids or calcitriol ointment to prevent skin atrophy. 1, 2
• Tacrolimus may be considered first-line for intertriginous areas. 5
• The warm, moist environment of flexural areas increases medication penetration but also significantly increases risk of atrophy with potent corticosteroids. 5

For scalp psoriasis:

• Use calcipotriene foam or calcipotriene plus betamethasone dipropionate gel for 4-12 weeks. 1, 2, 3

For nail psoriasis:

• Apply calcipotriene combined with betamethasone dipropionate, though efficacy is limited due to poor nail matrix penetration. 1
• Tazarotene 0.1% cream under occlusion for 12 weeks shows comparable efficacy to clobetasol. 1

Combination Strategies to Enhance Efficacy

Combine tazarotene with medium- or high-potency corticosteroids for 8-16 weeks to increase efficacy while reducing local adverse events and prolonging remission. 1 Apply tazarotene 0.1% gel once daily sparingly to lesions only, avoiding perilesional skin to minimize irritation. 5, 1

Systemic Therapy for Moderate-to-Severe Disease

When to Initiate Systemic Treatment

Patients with ≥5% BSA, inadequate response to topicals, or significant quality of life impact require phototherapy or systemic agents. 2, 3

Systemic Non-Biologic Options

Methotrexate:

• Inhibits dihydrofolate reductase and increases endogenous adenosine with anti-inflammatory effects. 5, 2
• Requires regular monitoring of complete blood count, liver function tests, and serum creatinine. 2, 3

Cyclosporine:

• Use 3-5 mg/kg/day for rapid onset of action, particularly effective for erythrodermic psoriasis requiring rapid response. 1
• Limit to short 3-4 month "interventional" courses. 1
• Requires monitoring of blood pressure, renal function, and lipid profile. 2, 3

Acitretin:

• Decreases keratinocyte hyperproliferation and restores normal epidermal differentiation. 5, 1
• Cannot be used in women of childbearing potential due to teratogenicity. 1
• Has slower onset of action compared to cyclosporine. 1

Biologic Therapies

TNF inhibitors, IL-17 inhibitors, IL-23 inhibitors, and IL-12/23 inhibitors are used for severe disease. 2, 3 Adding ultra-high potency topical corticosteroid to biologic therapy for 12 weeks accelerates clearance and improves outcomes. 2, 3

Critical Pitfalls to Avoid

• Never combine salicylic acid with calcipotriene simultaneously—the acidic pH inactivates calcipotriene and eliminates its effectiveness. 1, 2
• Avoid systemic corticosteroids in psoriasis—they cause disease flare during taper and may provoke pustular psoriasis. 2, 3, 4
• Do not use high-potency corticosteroids on face or flexures—use low-potency agents or tacrolimus instead to prevent skin atrophy. 1, 2
• Limit continuous high-potency corticosteroid use to prevent skin atrophy, striae, telangiectasia, and HPA axis suppression. 1, 2, 4

Special Considerations for Erythrodermic Psoriasis

For systemically ill patients with erythrodermic psoriasis, use oral cyclosporine 3-5 mg/kg/day due to rapid and impressive onset of action. 1 Base therapy on short-term efficacy rather than long-term considerations, then transition to maintenance therapy after acute illness improves. 1 Mid-potency topical corticosteroids and emollients under occlusion may help restore barrier function, but systemic treatment is inevitably necessary. 1