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 skin 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 even with limited BSA involvement 1, 3, 2
• Quality of life impact should drive treatment intensity regardless of physical extent 1, 3

Treatment Algorithm by Severity

Mild Psoriasis (<5% BSA)

First-Line Topical Therapy:

• Calcipotriene/betamethasone dipropionate combination product once daily for 4-8 weeks is the optimal first-line choice 1, 2
• This combination enhances efficacy and reduces irritation compared to monotherapy 1
• After achieving initial control, transition to weekend-only high-potency corticosteroid (twice daily on weekends) with weekday vitamin D analogue therapy (twice daily on weekdays) to minimize corticosteroid exposure while maintaining efficacy 2

Site-Specific Modifications:

• Scalp psoriasis: Calcipotriene foam or calcipotriene plus betamethasone dipropionate gel for 4-12 weeks 1, 2
• Facial/intertriginous psoriasis: Low-potency corticosteroids or tacrolimus 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
• Body/extremities: Class 2-5 (moderate to high potency) corticosteroids initially; for thick chronic plaques, use class 1 ultrahigh-potency agents like clobetasol propionate 0.05% or halobetasol propionate 0.05% 2

Moderate-to-Severe Psoriasis (≥5% BSA)

First-Line: Phototherapy

• 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 complete blood count, liver function tests, and serum creatinine 1, 2
• Cyclosporine 3-5 mg/kg/day for rapid onset, 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 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 1, 3
• Adalimumab (HUMIRA): 80 mg initial dose, followed by 40 mg every other week starting one week after initial dose for plaque psoriasis 4
• For psoriatic arthritis, adalimumab is effective for both skin and joint symptoms 3, 4

Combination Therapy Strategies for Moderate-to-Severe Disease

Adding topical therapy to biologics significantly accelerates clearance:

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

Psoriatic Arthritis Treatment

• 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

Critical Pitfalls to Avoid

• Never use systemic corticosteroids in psoriasis—they cause disease flare during taper 1, 3
• Never combine salicylic acid with calcipotriene simultaneously—the acidic pH inactivates calcipotriene and eliminates its effectiveness 2
• Limit continuous high-potency corticosteroid use to maximum 4 weeks to prevent skin atrophy, striae, telangiectasia, and HPA axis suppression 1, 2
• Do not use high-potency corticosteroids on face or flexures—use low-potency agents or tacrolimus instead 2
• Apply vitamin D analogues after phototherapy, not before, to avoid inactivation 3, 2
• Maximum vitamin D analogue use: 100g per week to avoid hypercalcemia 2
• All commonly used systemic agents are absolutely contraindicated in pregnancy 1
• Long-term use of high-potency corticosteroids beyond 12 weeks requires careful physician supervision 2

Maintenance Strategies

• Intermittent topical steroid application or vitamin D analogues help prolong remission 1, 2
• Rotational therapy (switching between treatment modalities every 1-2 years) may minimize cumulative toxicity of individual treatments 3