What are the treatment options for psoriasis?

Treatment for 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 skin in 48-74% of patients. 1, 2

Disease Severity Classification and Treatment Selection

Mild psoriasis is defined as <5% body surface area involvement in asymptomatic patients who are candidates for topical therapy alone 3. However, any patient with symptomatic psoriasis (pain, bleeding, itching) should be considered for systemic or phototherapy regardless of body surface area 1, 3.

Moderate-to-severe psoriasis (≥5% BSA or involvement of vulnerable areas) requires phototherapy or systemic agents as first-line treatment 1, 2.

First-Line Topical Therapy for Mild Psoriasis

Standard Body Areas (Trunk and Extremities)

• Apply calcipotriene/betamethasone dipropionate combination product once daily for 4-8 weeks 1, 2
• Alternatively, use high-potency corticosteroids such as clobetasol propionate 0.05% or halobetasol propionate 0.05% 3, 2
• Maximum vitamin D analogue use is 100g per week to avoid hypercalcemia 4, 1, 2

Site-Specific Modifications

For facial and intertriginous psoriasis:

• Use low-potency corticosteroids or calcitriol ointment to prevent skin atrophy 1, 3, 2
• Tacrolimus is also first-line for intertriginous psoriasis 4
• The warm, moist environment of flexural areas increases medication penetration but significantly increases risk of atrophy with potent corticosteroids 4

For scalp psoriasis:

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

For nail psoriasis:

• Apply calcipotriene combined with betamethasone dipropionate, though efficacy is limited due to poor nail matrix penetration 3
• Tazarotene 0.1% cream under occlusion for 12 weeks shows comparable efficacy to clobetasol 3

Maintenance Therapy Strategy

After achieving initial control with combination therapy:

• Transition to weekend-only high-potency corticosteroid application (twice daily on weekends) with weekday vitamin D analogue therapy (twice daily on weekdays) 3, 2
• This approach minimizes corticosteroid exposure while maintaining efficacy 3

Combination Strategies to Enhance Efficacy

Tazarotene plus corticosteroids:

• Combining tazarotene 0.1% gel once daily with medium/high-potency corticosteroid for 8-16 weeks produces synergistic effects while reducing local adverse events and prolonging remission 3
• Apply tazarotene sparingly to lesions only, avoiding perilesional skin to minimize irritation 4, 3

Emollients as corticosteroid-sparing agents:

• Water-in-oil cream or lotion combined with betamethasone dipropionate increases efficacy while achieving control with fewer steroid applications 4

Phototherapy for Moderate-to-Severe Psoriasis

For patients with ≥5% BSA or inadequate response to topicals, initiate phototherapy as first-line systemic treatment 2:

• Narrowband UVB is preferred 1
• 308-nm excimer laser allows selective targeting of localized resistant areas such as scalp and skin folds 4
• Apply vitamin D analogues after phototherapy to avoid inactivation 1, 3

Systemic Non-Biologic Therapies

Methotrexate

• FDA-approved since 1972, methotrexate is a competitive inhibitor of dihydrofolate reductase 4
• Requires regular monitoring of complete blood count, liver function tests, and serum creatinine 2

Cyclosporine

• For rapid onset of action, use cyclosporine 3-5 mg/kg/day, particularly effective for erythrodermic psoriasis requiring rapid response 3
• Should be used in short 3-4 month "interventional" courses 3
• Requires monitoring of blood pressure and renal function 2

Acitretin

• Decreases keratinocyte hyperproliferation and restores normal epidermal differentiation 4, 3, 2
• Cannot be used in women of childbearing potential due to teratogenicity 3
• Has slower onset of action compared to cyclosporine 3

Biologic Therapies for Severe Disease

TNF inhibitors, IL-17 inhibitors, IL-23 inhibitors, and IL-12/23 inhibitors are third-line options for severe disease 1, 2:

Adalimumab (HUMIRA) is FDA-approved for moderate to severe chronic plaque psoriasis in adults who are candidates for systemic therapy or phototherapy when other systemic therapies are medically less appropriate 5:

• Initial dose: 80 mg subcutaneously, followed by 40 mg every other week starting one week after initial dose 5
• Boxed warning: Increased risk of serious infections (including tuberculosis) and malignancies, including lymphoma 5
• Perform test for latent TB before starting; if positive, treat TB prior to initiating adalimumab 5

Adding topical corticosteroids to biologic therapy accelerates clearance and improves outcomes 2. Specifically, adding ultra-high potency topical corticosteroid to etanercept for 12 weeks enhances efficacy 2.

Critical Pitfalls to Avoid

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

Special Considerations

For genital psoriasis:

• This location causes significant psychological impact regardless of overall disease severity 4
• Use low-potency corticosteroids or dilute calcipotriene with moisturizer (though this may affect calcipotriene stability) 4
• The warm, moist environment facilitates medication penetration but increases risk of irritation and atrophy 4

For erythrodermic psoriasis:

• Base therapy on short-term efficacy: oral cyclosporine 3-5 mg/kg/day is the logical choice due to rapid onset of action 3
• Mid-potency topical corticosteroids and emollients under occlusion may help restore barrier function, but systemic treatment is inevitably necessary 3
• Transition to maintenance therapy after acute illness improves 3

For psoriatic arthritis:

• TNF inhibitors like adalimumab are effective for both skin and joint symptoms 1