What is the recommended treatment approach for an adult with psoriasis?

Treatment of Psoriasis in Adults

Initial Treatment Strategy Based on Disease Severity

For mild-to-moderate psoriasis, initiate treatment with high-potency topical corticosteroids (class 1-3) combined with vitamin D analogues, while moderate-to-severe disease requires biologic therapy as first-line systemic treatment. 1, 2, 3

Defining Disease Severity

• Mild-to-moderate disease: Body surface area (BSA) <5% or PASI <10 1
• Moderate-to-severe disease: BSA ≥5% or PASI ≥10 with DLQI >10 3
• Severe disease regardless of BSA: Involvement of high-impact areas (face, genitals, hands, feet, scalp, nails) or presence of psoriatic arthritis 1, 2

Treatment Algorithm for Mild-to-Moderate Psoriasis

First-Line Topical Therapy (2-4 weeks)

• Ultrahigh-potency corticosteroids (class 1) such as clobetasol propionate 0.05% or halobetasol propionate 0.05% applied twice daily for 2-4 weeks achieve 58-92% efficacy rates 1, 4
• Combination therapy with calcipotriene (vitamin D analogue) plus corticosteroids provides superior efficacy compared to either agent alone and should be used as initial treatment 2, 5
• Lower potency corticosteroids must be used on face, intertriginous areas, and areas susceptible to atrophy 1

Second-Line: Phototherapy

• Narrowband UVB phototherapy is recommended if inadequate response to topical therapy after 4 weeks 1, 2

Common Pitfalls to Avoid

• Never use systemic corticosteroids (prednisone) for psoriasis due to poor long-term efficacy, significant safety concerns, and risk of rebound flares 2, 3
• Avoid prolonged continuous use of ultrahigh-potency corticosteroids beyond 4 weeks due to risk of skin atrophy and other adverse effects 1

Treatment Algorithm for Moderate-to-Severe Psoriasis

First-Line Biologic Selection

Adalimumab is the preferred first-line biologic agent for moderate-to-severe plaque psoriasis, dosed at 80 mg subcutaneous initial dose, followed by 40 mg one week later, then 40 mg every 2 weeks, achieving PASI 75 in 71% of patients at week 16 1, 3

Alternative First-Line Biologics Based on Clinical Context:

• Ustekinumab (IL-12/23 inhibitor): Recommended as first-line biologic by British guidelines, dosed at 45 mg (if <100 kg) or 90 mg (if >100 kg) subcutaneous at weeks 0,4, then every 12 weeks 1
• Secukinumab (IL-17 inhibitor): Consider as first-line for highest efficacy (PASI 90 achievement), with or without psoriatic arthritis 1, 2
• Infliximab (TNF-α inhibitor): Alternative first-line option dosed at 5 mg/kg IV at weeks 0,2,6, then every 8 weeks, achieving PASI 75 in 80% of patients, but requires addition of methotrexate to reduce immunogenicity 1, 3

Biologic Selection Based on Comorbidities

• Adalimumab is strongly recommended for psoriatic arthritis of any severity, as it treats both skin and joint symptoms and inhibits radiographic joint damage 1, 3
• Avoid TNF-α inhibitors in patients with heart failure (NYHA class III/IV), demyelinating disease, or recurrent infections 2
• Avoid IL-17 inhibitors in patients with inflammatory bowel disease 2

Site-Specific Recommendations

• Palmoplantar psoriasis: Infliximab or adalimumab recommended 1, 3
• Nail psoriasis: Infliximab, adalimumab, or etanercept recommended 1, 3
• Scalp psoriasis: Infliximab or etanercept recommended 1, 6, 3
• Pustular or erythrodermic psoriasis: Infliximab, etanercept, or brodalumab (for generalized pustular) 1, 6

Combination Therapy to Augment Efficacy

• Add high-potency topical corticosteroids ± vitamin D analogues to biologic therapy during the first 12-16 weeks to accelerate clearance 1, 3
• Methotrexate combinations with TNF-α inhibitors are recommended to reduce immunogenicity and prevent antibody formation, particularly essential with infliximab 1, 3

Assessment of Treatment Response

Timing of Assessment

• Etanercept: Assess at 12 weeks 3
• Adalimumab: Assess at 16 weeks 3
• Infliximab: Assess at 10-14 weeks 3

Defining Treatment Success

• Minimal response criteria: ≥50% reduction in baseline PASI (PASI 50) AND ≥4-point improvement in DLQI 1
• Optimal response: PASI 75 (75% improvement from baseline) 3

Management of Inadequate Response

Primary Failure (No Initial Response)

• Switch to alternative biologic class if minimal response criteria not met at appropriate timepoint 1
• Consider dose escalation if inadequate response may be due to insufficient dosing (obesity, early relapse during treatment cycle) 1

Dose Escalation Strategies (when funded and feasible):

• Adalimumab: Increase from 40 mg every 2 weeks to 40 mg weekly 1
• Ustekinumab: Increase from 45 mg to 90 mg every 12 weeks (<100 kg), or from 90 mg every 12 weeks to every 8 weeks (>100 kg) 1
• Infliximab: Increase frequency from every 8 weeks to every 6 weeks, or increase dose up to 10 mg/kg 1

Secondary Failure (Loss of Response)

• Switch to alternative biologic agent from different class 1
• Any currently licensed biologic can be used as second-line therapy after first biologic failure 1

Reserve Infliximab Strategy

• Infliximab should be reserved for very severe disease or where other available biologic agents have failed or cannot be used 1

Pre-Treatment Screening and Monitoring

Baseline Screening Before Biologic Initiation

• Tuberculosis testing (PPD or IGRA) 6, 7
• Hepatitis B and C serology 6, 7
• Complete blood count 6
• Comprehensive metabolic panel 6

Ongoing Monitoring

• Yearly tuberculosis testing for patients on biologic therapy 6
• Monitor for infections during therapy, as biologics increase infection risk through immunosuppression 6, 7
• Assess for development or exacerbation of inflammatory bowel disease when using IL-17 inhibitors 6

Special Considerations

Systemic Non-Biologic Agents

• Acitretin is indicated for severe psoriasis in adults but should be reserved for patients unresponsive to other therapies due to significant adverse effects, particularly teratogenicity in females of reproductive potential 8
• Methotrexate, cyclosporine, and acitretin are conventional systemic therapies that patients should fail, have contraindications to, or be intolerant of before initiating biologics 3