What is the initial treatment for psoriasis?

Initial Treatment for Psoriasis

Topical corticosteroids, vitamin D analogues, coal tar preparations, and dithranol/anthralin are the recommended first-line therapy for mild to moderate psoriasis. 1

Treatment Algorithm Based on Disease Severity

Mild to Moderate Psoriasis (Limited Disease)

1. First-line topical treatments:

   • Topical corticosteroids: Select potency based on location
     • Class 1 (Ultrahigh-potency): Clobetasol propionate, halobetasol propionate for thick plaques
     • Class 2-5 (High to moderate potency): Betamethasone dipropionate, triamcinolone acetonide for body
     • Class 6-7 (Low potency): Hydrocortisone, desonide for face/intertriginous areas 1
   • Vitamin D analogues: Calcipotriene, calcipotriol, calcitriol
   • Combination therapy: Corticosteroid + vitamin D analogue (more effective than either alone) 2

2. Treatment approach:

   • Initial treatment: Apply twice daily for 2-4 weeks
   • Maintenance: Weekend-only corticosteroid application with vitamin D analogue 5 days/week 2, 1
   • Maximum 100g of vitamin D analogues per week to avoid hypercalcemia 2

Special Locations

• Scalp psoriasis: Corticosteroid solutions/foams, shampoos with coal tar or salicylic acid 1, 3
• Facial/intertriginous psoriasis: Low-potency corticosteroids or calcineurin inhibitors (tacrolimus, pimecrolimus) 1, 3
• Nail psoriasis: Vitamin D analogues with betamethasone dipropionate 1

Moderate to Severe Psoriasis

When topical therapy is insufficient, progress to:

1. Phototherapy: NB-UVB or PUVA 1, 4
2. Systemic agents:
   • Methotrexate: Especially useful for acute generalized pustular psoriasis, erythroderma, psoriatic arthritis 2
   • Cyclosporine: For rapid response in severe cases 1
   • Acitretin: Particularly effective for pustular forms 2
3. Biologics: TNF-α inhibitors (adalimumab, infliximab, etanercept) for cases failing traditional therapy 1

Practical Considerations

Corticosteroid Use

• Avoid long-term continuous use: Risk of skin atrophy and systemic absorption 2
• Rotation strategy: Combine with steroid-sparing agents to minimize side effects 1, 5
• Occlusion: Increases potency but also increases risk of side effects 2
• Tachyphylaxis: Often due to poor adherence rather than receptor down-regulation 2

Special Clinical Variants

• Guttate psoriasis: Screen for streptococcal infection and treat with antibiotics if positive 1
• Erythrodermic psoriasis: May require hospitalization; cyclosporine (3-5 mg/kg/day) for rapid response 1

Monitoring

• Regular clinical assessment to monitor treatment response and adverse effects
• For methotrexate: Full blood count, liver function tests, serum creatinine initially weekly, then every 1-2 months 2
• Avoid systemic corticosteroids as withdrawal can precipitate erythrodermic or pustular psoriasis 1

Pitfalls and Caveats

• Drug interactions: Methotrexate interacts with alcohol, salicylates, NSAIDs, co-trimoxazole, trimethoprim, probenecid, phenytoin, retinoids, pyrimethamine, and frusemide 2
• Contraindications for methotrexate: Pregnancy, breastfeeding, wish to father children, significant hepatic damage, blood disorders 2
• Contraindications for retinoids: Pregnancy or wish to conceive within two years (teratogenic potential) 2
• Beta-blockers: May worsen psoriasis; avoid if possible 1

The evidence strongly supports starting with topical therapy for mild to moderate disease, with a combination of corticosteroids and vitamin D analogues offering the best efficacy while minimizing side effects. For more severe disease, systemic agents should be considered, with methotrexate being particularly useful for specific clinical variants.