How to manage a patient with a history of psoriasis?

Management of Psoriasis: A Structured Clinical Approach

For patients with limited disease (<5% body surface area), initiate treatment with high-potency topical corticosteroids combined with calcipotriene (vitamin D analog), which achieves 58-92% clearance rates and represents the most effective first-line therapy. 1

Initial Assessment Framework

Assess severity using two critical components: the patient's perception of disability ("need for treatment") and objective body surface area involvement using body mapping or PASI scoring. 2 The diagnosis is clinical based on characteristic erythematous, scaly plaques in typical distributions—laboratory investigations are rarely helpful and should not delay treatment. 2, 3

Screen immediately for medications that worsen psoriasis:

• Absolutely avoid: Lithium, chloroquine, and mepacrine (associated with severe, potentially fatal deterioration) 2, 1
• Use caution with: Beta-blockers, NSAIDs, and alcohol (may precipitate or worsen disease in some patients) 2, 1

Treatment Algorithm Based on Disease Severity

Mild Disease (<5% BSA): Topical Therapy

First-line regimen for body plaques:

• Apply clobetasol propionate 0.05% or betamethasone dipropionate 0.05% twice daily for maximum 2-4 weeks 1, 4
• Combine with calcipotriene (vitamin D analog) for synergistic effect superior to either agent alone 3
• Fixed-combination products (calcipotriene/betamethasone dipropionate gel or foam) provide convenient once-daily application for 4-12 weeks 1

Location-specific modifications:

• Scalp: Clobetasol propionate 0.05% shampoo twice weekly provides rapid symptom relief within 3-4 weeks 1
• Face, genitals, intertriginous areas: Use low-potency corticosteroids or topical calcineurin inhibitors to minimize atrophy risk 2, 1

Critical safety monitoring for topical corticosteroids:

• Implement mandatory clinical review every 4 weeks with no unsupervised repeat prescriptions 2, 1
• Limit moderate-potency corticosteroid use to maximum 100g per month 2, 1
• Require dermatological supervision for class 1-2 (very potent/potent) preparations 2, 1
• Implement periods each year when alternative treatments are employed to prevent tachyphylaxis 4

If inadequate response to first topical agent: Trial alternative topical agents before escalating to systemic therapy, as patients failing one agent may respond to another. 2, 3 Options include:

• Coal tar: Start with 0.5-1.0% crude coal tar in petroleum jelly, increase concentration every few days to maximum 10% (extremely safe, messier but more effective than refined products) 2, 4
• Dithranol (anthralin): Start at 0.1-0.25% concentration, increase in doubling concentrations as tolerated; use "short contact mode" (15-45 minutes every 24 hours) to minimize irritancy and staining 2, 4
• Tazarotene: Add to moderate-to-high potency corticosteroids for body plaques to reduce irritation while enhancing efficacy 2, 1, 3

Moderate-to-Severe Disease (≥5% BSA): Systemic Therapy

Escalate to systemic therapy when:

• Body surface area involvement exceeds 5% 2, 1
• Inadequate response to optimized topical therapy after 8 weeks 1, 4
• Signs of erythrodermic or pustular psoriasis develop 1
• Psoriatic arthritis requires systemic treatment 2

Systemic treatment hierarchy:

1. Photochemotherapy (PUVA) - First-line systemic option:

   • Least toxic systemic agent and generally considered first-choice 1, 3, 4
   • Start at 70% of minimum phototoxic dose 1, 4
   • Increase successive doses by 40% of preceding dose if no erythema develops 4
   • Expect response within 4 weeks 4

2. Conventional systemic agents (require dermatology supervision):

   • Methotrexate: Response time 2 weeks; absolute contraindications include pregnancy, breastfeeding, wish to father children, significant hepatic damage, anemia, leucopenia, thrombocytopenia 1, 4
   • Acitretin: Response time 6 weeks; requires contraception with absolute contraindication for pregnancy or wish to conceive within 2 years of stopping 1
   • Cyclosporin: Response time 3 weeks; contraindicated with abnormal renal function, uncontrolled hypertension, or malignancy 1

3. Biologic therapy (for moderate-to-severe disease):

   • The American Academy of Dermatology-National Psoriasis Foundation guidelines recommend biologics as first-line treatment option for moderate-to-severe plaque psoriasis due to efficacy and acceptable safety profiles 5
   • Adalimumab (TNF-α inhibitor): Can be combined with methotrexate or topical high-potency corticosteroids, achieving treatment goals in 68.2-79.3% of patients by week 16 4
   • Before initiating biologics: Screen for active or latent tuberculosis, hepatitis B, and fungal infections; counsel on increased risk of serious infections and cancer 6

Special Considerations for Pustular Psoriasis

Infliximab demonstrates rapid and often complete disease clearance for generalized pustular psoriasis and should be considered first-line biologic therapy, with standard dosing of 5 mg/kg infused at weeks 0,2, and 6, then every 8 weeks thereafter. 1, 4

Alternative option: Acitretin for pustular psoriasis 1

Critical Medications to NEVER Prescribe

Never prescribe systemic corticosteroids for psoriasis—they can precipitate erythrodermic psoriasis, generalized pustular psoriasis, or very unstable disease when discontinued, potentially causing severe or fatal deterioration. 1, 3, 4

Common Pitfalls to Avoid

Perceived "tachyphylaxis" to topical corticosteroids is usually poor patient adherence, not true receptor down-regulation. Address compliance issues before switching therapies. 3, 4 Patients who fail one topical agent may respond to another—trial alternatives before escalating. 2, 3

Never combine salicylic acid with calcipotriene: Acidic pH inactivates calcipotriene and reduces effectiveness. 1

Care Coordination

Most patients with stable chronic plaque psoriasis and guttate psoriasis should be cared for by general practitioners. 2 Patients with severe psoriasis requiring systemic agents should be under continuing supervision of a consultant dermatologist because of potential drug toxicity. 2