Treatment for Psoriasis
For mild psoriasis (<5% body surface area), initiate treatment with high-potency topical corticosteroids (class 2-5) combined with calcipotriene for 2-4 weeks, achieving 58-92% clearance rates. 1, 2
Topical Therapy for Mild Disease
First-line combination therapy is the most effective approach for localized psoriasis:
- Apply high-potency topical corticosteroids (clobetasol propionate 0.05% or betamethasone dipropionate 0.05%) twice daily for maximum 2-4 weeks, combined with calcipotriene for synergistic effect 1, 2
- Use low-potency corticosteroids or topical calcineurin inhibitors (tacrolimus 0.1%) on the face, genitals, and intertriginous areas to avoid skin atrophy 1, 3
- For scalp involvement, use topical corticosteroids (class 1-7) for at least 4 weeks 1
Maintenance regimen after initial clearance:
- Apply corticosteroids on weekends only while using vitamin D analogs (calcipotriene) on weekdays to prevent tachyphylaxis 1
- Limit moderate-potency corticosteroid use to maximum 100g per month 1, 3
Alternative topical agents when first-line fails:
- Add tazarotene (topical retinoid) to moderate-to-high potency corticosteroids to reduce irritation while enhancing efficacy 1, 3
- Start coal tar at 0.5-1.0% concentration and increase gradually to maximum 10% 1, 3
Systemic Therapy for Moderate-to-Severe Disease
Escalate to systemic therapy when body surface area exceeds 5%, or when topical therapy fails after 8 weeks, or when psoriasis affects quality of life despite limited body surface involvement. 4, 3
Phototherapy as First-Line Systemic Treatment
- Photochemotherapy (PUVA) is the least toxic systemic agent and should be considered first-line systemic treatment, starting at 70% of minimum phototoxic dose and increasing successive doses by 40% if no erythema develops 2, 3
- Narrowband UVB phototherapy is first-line for pregnant women with moderate to severe psoriasis, as it lacks systemic toxicities 2
Conventional Systemic Agents
When phototherapy is inadequate or unavailable:
Methotrexate is especially useful in acute generalized pustular psoriasis, psoriatic erythroderma, psoriatic arthritis, and extensive chronic plaque psoriasis, with response time of 2 weeks 2, 3
- Absolute contraindications include pregnancy, breastfeeding, wish to father children, significant hepatic damage, anemia, leucopenia, thrombocytopenia 3
Cyclosporine is first-line for erythrodermic psoriasis, with dramatic improvement during 2-3 weeks 2
Acitretin has response time of 2-6 weeks but is contraindicated in pregnancy 3
Biologic Therapy
For moderate-to-severe psoriasis when conventional systemic agents are contraindicated or ineffective:
- Biologics (adalimumab, infliximab, ustekinumab, etanercept) achieve treatment goals in 68.2-79.3% of patients by week 16 2, 3
- 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 2, 3
- Adalimumab dosing for plaque psoriasis: 80 mg initial dose, followed by 40 mg every other week starting one week after initial dose 5
- Screen for active or latent tuberculosis, hepatitis B, and fungal infections before initiating biologics 3, 5
Critical Medications to Absolutely Avoid
NEVER prescribe systemic corticosteroids for psoriasis—they precipitate erythrodermic psoriasis, generalized pustular psoriasis, or very unstable disease upon discontinuation. 1, 2, 3
Other medications that cause severe, potentially fatal psoriasis deterioration:
- Lithium, chloroquine, and mepacrine are absolutely contraindicated 1, 2, 3
- Beta-blockers and non-steroidal anti-inflammatory drugs can worsen psoriasis in some patients 1
- Avoid simultaneous use of salicylic acid with calcipotriol, as the acidic pH inactivates calcipotriol 1
Common Pitfalls and How to Avoid Them
- Perceived "tachyphylaxis" to topical corticosteroids is usually due to poor patient adherence rather than true receptor down-regulation—address compliance issues before switching therapies 1, 3
- Patients who fail to respond to one topical agent may respond to another for unclear reasons—trial alternative topical agents before escalating to systemic therapy 1, 3
- Avoid prescribing refills without medical supervision and ensure regular clinical follow-up when using topical corticosteroids 1
- Plan annual periods where alternative treatments are employed to prevent long-term complications 1, 3
Referral to Dermatology
- Most patients with chronic stable plaque psoriasis can be managed in primary care 1
- Refer patients requiring systemic agents to a dermatologist due to potential toxicity and need for specialized monitoring 4, 1
- Refer patients with psoriatic arthritis, erythrodermic psoriasis, or generalized pustular psoriasis for specialist management 4, 2