What is the recommended management approach for a patient with psoriasis?

Management Approach to Psoriasis

Begin with high-potency topical corticosteroids combined with calcipotriol for mild psoriasis (less than 3% body surface area), escalate to phototherapy (narrowband UVB or PUVA) when body surface area exceeds 5% or after 8 weeks of failed topical therapy, and reserve biologics or conventional systemic agents for moderate-to-severe disease that fails phototherapy. 1, 2

Initial Assessment and Disease Severity Classification

• Classify psoriasis severity as mild (less than 3% BSA), moderate (3-10% BSA), or severe (greater than 10% BSA), considering both objective measures (PASI score, BSA) and subjective impact on quality of life (DLQI) 2
• Assess for psoriatic arthritis, cardiometabolic comorbidities, and mental health disorders, as these significantly impact treatment selection and prognosis 3

First-Line Treatment: Topical Therapy for Mild Psoriasis

• Apply high-potency topical corticosteroids (Class 1-2) twice daily to thick plaques for maximum 2-4 weeks, combined with calcipotriol to achieve 58-92% clearance rates 1
• Use low-potency corticosteroids or topical calcineurin inhibitors on sensitive areas (face, genitals, intertriginous regions) to minimize atrophy risk 1, 2
• Add tazarotene to moderate-to-high potency corticosteroids for body plaques to reduce irritation and enhance efficacy 1
• Limit moderate-potency corticosteroid use to maximum 100g per month and implement periods each year when alternative treatments are employed to prevent tachyphylaxis 1

Alternative Topical Options When First-Line Fails

• Start with 0.5-1.0% crude coal tar in petroleum jelly and increase concentration every few days to maximum 10% 1
• Dithranol (anthralin) can be started at 0.1-0.25% concentration and increased in doubling concentrations as tolerated, using short contact mode (15-45 minutes every 24 hours) 1

Critical Topical Therapy Pitfall

• Perceived "tachyphylaxis" to topical corticosteroids is often due to poor patient adherence rather than true receptor down-regulation—address compliance issues before switching therapies 1
• Patients who fail one topical agent may respond to another; trial alternative topical agents before escalating to systemic therapy 1

Second-Line Treatment: Phototherapy

• Escalate to phototherapy when body surface area involvement exceeds 5%, or when there is inadequate response to optimized topical therapy after 8 weeks 1
• Narrowband UVB is the first-line phototherapy with fewer side effects than PUVA 2
• PUVA (psoralens plus ultraviolet A) 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 4, 1, 2
• Treatments should be given no more frequently than every 48 hours, with courses typically lasting 8-10 weeks 4
• Avoid commercially available sunbeds (which emit ultraviolet A alone) as they are rarely effective and may cause premature skin aging and increased skin fragility 4

Phototherapy Supervision Requirements

• A senior clinician with adequate training and continuing interest in phototherapy should supervise the service 4
• All phototherapy equipment must be adequately maintained and regularly calibrated by trained personnel 4
• Maintain accurate records of dosage and number of treatments for each patient 4

Third-Line Treatment: Conventional Systemic Agents

The decision to move from topical to systemic treatment should be made by a senior dermatologist experienced in managing psoriasis, based on objective disease severity plus social and psychological factors. 4

Indications for Systemic Treatment

• Failure of adequate trial of topical treatment 4
• Repeated hospital admissions for topical treatment 4
• Extensive chronic plaque psoriasis in elderly or infirm patients 4, 1
• Severe psoriatic arthropathy 4, 1

Methotrexate (FDA-Approved Since 1972)

• Start at 15 mg weekly, maximum 25-30 mg weekly, with response time of 2-6 weeks 1, 2
• Works through multiple mechanisms including inhibition of dihydrofolate reductase and increasing endogenous adenosine 1
• Absolute contraindications: pregnancy, breastfeeding, wish to father children, significant hepatic damage, anemia, leucopenia, thrombocytopenia 4, 1
• Obtain baseline CBC, liver function tests, and serum creatinine, with regular hepatic monitoring 1, 2
• May cause renal damage leading to acute renal failure, particularly at high doses 5
• Severe dermatologic reactions including toxic epidermal necrolysis and Stevens-Johnson syndrome have been reported 5

Cyclosporine

• Dose: 2.5-5 mg/kg daily, with response time of approximately 3 weeks 1, 2
• Obtain baseline serum creatinine and blood pressure before initiating, with regular monitoring of both parameters due to glomerulosclerosis and hypertension risk 1, 2
• Requires careful monitoring of blood pressure and renal function 1

Acitretin

• Dose: 25-50 mg daily, particularly effective for pustular psoriasis, with response as early as 3 weeks 1, 6, 2
• Obtain baseline CBC, lipid panel, and liver function tests before initiating, with ongoing monitoring of lipids and hepatic function 6, 2
• Absolutely contraindicated in pregnancy—explain teratogenic risks and document that women of childbearing age understand the absolute necessity for reliable contraception 4, 6

Fourth-Line Treatment: Biologic Therapy

• Biologics are recommended as an option for first-line treatment of moderate-to-severe plaque psoriasis because of their efficacy and acceptable safety profiles 3
• TNF-α inhibitors (etanercept, adalimumab, certolizumab, infliximab) are first-line biologic therapy for psoriasis with associated arthritis 2, 3
• IL-17 inhibitors (secukinumab, ixekizumab, brodalumab) and p19IL-23 inhibitors (guselkumab, tildrakizumab, risankizumab) are highly effective alternatives 3
• Biologics can be combined with methotrexate or topical high-potency corticosteroids, achieving treatment goals in 68.2-79.3% of patients by week 16 1

Critical Safety Considerations for Biologics

• Screen for active or latent tuberculosis, hepatitis B, and fungal infections before initiating biologics due to increased infection risk 1, 6
• Monitor for serious infections and cancer risk 1

Special Considerations: Pustular Psoriasis

Generalized Pustular Psoriasis

• Hospital admission is required for patients presenting with generalized pustular or erythrodermic psoriasis due to risk of systemic involvement and potential mortality 4, 6
• Infliximab demonstrates rapid and often complete disease clearance 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, 6
• Acitretin (25-50 mg daily) is the preferred conventional systemic agent for pustular psoriasis 6

Localized Pustular Psoriasis of Palms and Soles

• Start with moderately potent topical corticosteroids (British National Formulary grade III) to relieve symptoms 4, 6
• Topical coal tar and dithranol may provide some benefit when corticosteroids are insufficient 4, 6
• Systemic acitretin can be considered for refractory localized disease 6

Critical Medications to AVOID

• NEVER prescribe systemic corticosteroids for psoriasis—they precipitate erythrodermic psoriasis, generalized pustular psoriasis, or very unstable psoriasis when discontinued, potentially causing fatal deterioration 4, 1, 6, 2
• Avoid lithium, chloroquine, and mepacrine, which may cause severe, potentially fatal deterioration 1
• In rare instances, treatment or withdrawal of corticosteroids in psoriasis is thought to have exacerbated the disease or provoked the pustular form 7

Pregnancy Considerations

• All commonly used systemic agents (methotrexate, cyclosporine, acitretin, biologics) are absolutely contraindicated in pregnancy 4, 6, 2
• Before prescribing to women of childbearing age, explicitly explain teratogenic risks and document that the patient understands the absolute necessity for reliable contraception 4, 6

Combination Therapy Considerations

• Combination therapies are widely used and adjunctive topical therapies with biologics, conventional systemic agents, and phototherapy provide clinical benefits 8
• Combination treatment with two or more systemic agents requires extreme caution because toxicity is at least additive—special attention should be paid to careful monitoring 4, 2
• Calcipotriene may enhance the effect of UVR to induce skin tumors; patients applying calcipotriene to exposed portions should avoid excessive exposure to natural or artificial sunlight 9

Special Clinical Scenario: Guttate Psoriasis

• A proportion of patients with acute guttate psoriasis have evidence of streptococcal infection—investigate and treat persistent streptococcal infection with phenoxymethyl penicillin or erythromycin 4
• Repeated attacks of guttate psoriasis after well-documented episodes of tonsillitis is an indication for referral to an otolaryngologist for consideration of tonsillectomy 4
• Use low concentrations of tar and dithranol, as acute guttate psoriasis is particularly sensitive to topical treatment 4
• Ultraviolet B radiation may be especially helpful 4