What does a nurse practitioner need to know about the evaluation and management of psoriasis?

What a Nurse Practitioner Needs to Know About Psoriasis

Nurse practitioners can independently manage most patients with mild-to-moderate chronic plaque psoriasis and guttate psoriasis using topical therapies, but must refer patients requiring systemic agents to dermatology due to potential drug toxicity. 1

Clinical Diagnosis and Assessment

Psoriasis diagnosis is purely clinical—laboratory tests are rarely helpful 1. You need to recognize that psoriasis exists in multiple forms that can transform over time, ranging from stable plaques to unstable eruptive inflammatory lesions that react poorly to topical treatment 1.

Severity Assessment Has Two Components:

1. Patient's subjective disability ("need for treatment")—this drives treatment decisions
2. Objective body surface area involvement—use body mapping or area/severity indices 1

Critical pitfall: Don't automatically escalate to systemic therapy just because topical treatment fails. Patients with limited disease may face more risk from systemic medications than from the disease itself 2.

Drug-Induced Exacerbations You Must Screen For

Be vigilant about medications that worsen psoriasis 1:

• Life-threatening deterioration: Lithium, chloroquine, mepacrine
• Common triggers: Beta-blockers, NSAIDs, alcohol
• Always review the medication list before starting treatment

Topical Therapy Management (Your Primary Role)

For chronic plaque psoriasis, most patients respond to topical agents. Options include no treatment, emollients alone, or active topical therapy with coal tar, dithranol (anthralin), or corticosteroids 1.

Coal Tar Protocol:

• Extremely safe for long-term use 1
• Start with 0.5-1.0% crude coal tar in petroleum jelly
• Increase concentration every few days up to 10%
• Cruder extracts are messier but more effective than refined products 1

Dithranol (Anthralin) Protocol:

• Start at 0.1-0.25% concentration
• Double the concentration as tolerated based on response and irritation 1
• Warn patients explicitly about skin/clothing staining and irritancy
• Avoid face, flexures, and genitalia
• Consider "short contact mode" (15-45 minutes daily) for better tolerability 1

Topical Corticosteroid Guidelines (Strict Monitoring Required):

You must follow these rules 1:

• Regular clinical review—no unsupervised refills
• Maximum 100g monthly of moderately potent (BNF grade III) preparations
• Mandate treatment-free periods annually with alternative agents
• Very potent or potent preparations require dermatology supervision

Key strategy: If one topical agent fails, try another before escalating—patients often respond differently to various topical therapies 1.

When to Refer to Dermatology

Immediate dermatology referral is required for 1:

• Patients needing systemic therapy (methotrexate, cyclosporine, acitretin, biologics)
• Severe psoriasis unresponsive to topical management
• Patients requiring very potent/potent topical corticosteroids

Systemic Therapy Awareness (Dermatology-Managed)

While dermatology manages these patients, you need baseline knowledge 2:

Methotrexate:

• Hepatotoxic potential
• Contraindicated: pregnancy, renal impairment, hepatitis/cirrhosis, alcoholism, unreliable patients
• Teratogenic and decreases sperm count
• Common drug interactions causing bone marrow suppression

Cyclosporine:

• Works rapidly but only for short courses (3-4 months)
• Monitor for renal dysfunction, hypertension, lymphoma risk
• Numerous drug interactions

Acitretin:

• Not immunosuppressive
• Severely limited in women: teratogenic with 3-year post-treatment pregnancy restriction

Biologics (T-cell and TNF Inhibitors):

Before initiating, obtain 2:

• Chemistry panel with liver function tests
• Complete blood count with platelets
• Hepatitis panel
• Tuberculosis testing

Hold biologics during active serious infections requiring antibiotics 2.

Comorbidity Screening and Counseling

You must counsel patients on lifestyle factors that worsen psoriasis and increase comorbidity risk 3:

Smoking:

• Increases psoriasis severity (OR 1.78) 3
• Severity correlates with cigarettes/day and years smoked
• Cessation progressively improves psoriasis over time
• Refer patients with nicotine dependency to cessation specialists 3

Alcohol:

• Increases disease severity (OR 2.1 for >2 drinks daily) 3
• Limits systemic treatment options due to hepatotoxicity concerns
• Refer patients with alcohol dependency for specialized support 3

Screen for Associated Comorbidities:

• Cardiovascular disease, diabetes, hypertension 4
• Psoriatic arthritis—refer to rheumatology when suspected 2
• Depression and anxiety—treatment may improve with psoriasis control 3

Patient Relationship and Adherence

Your unique role involves building meaningful relationships to optimize adherence 4, 5. This includes:

• Setting realistic treatment expectations
• Facilitating conversations about disease management
• Addressing barriers: injection fears, cost concerns, insurance issues, knowledge gaps 4
• Collaborating with dermatology and other specialists 5

Treatment Goals

Define clear targets 6:

• Minimum acceptable: PASI 75 response
• Desirable goal: PASI 90 or absolute PASI <2

Remember: Psoriasis has no cure—treatment is suppressive, aiming for remission or tolerable disease burden. Relapses are unpredictable and cannot be prevented with topical agents alone 1.