What is the outline for evaluating and treating a patient with psoriasis?

History and Examination of Psoriasis: Clinical Evaluation Outline

Begin by diagnosing psoriasis clinically based on characteristic erythematous, scaly plaques with silvery scale, typically on extensor surfaces, without requiring laboratory investigations in most cases 1.

Initial Clinical Assessment

Skin Examination - Key Features to Document

• Plaque characteristics: Look for well-demarcated, raised erythematous plaques covered with silvery-white scale on extensor surfaces (elbows, knees), scalp, and trunk 1, 2
• Distribution pattern: Document involvement of special areas including scalp, nails, face, intertriginous regions, and palmoplantar surfaces 3
• Nail involvement: Examine for pitting, onycholysis, oil spots, and subungual hyperkeratosis, which particularly supports diagnosis when associated with distal interphalangeal joint disease 1
• Clinical variants: Identify the specific type - plaque (90% of cases), guttate, erythrodermic, pustular, inverse, or nail psoriasis 2, 4

Severity Assessment - Quantify Disease Burden

• Body Surface Area (BSA): Measure at every visit; BSA ≥10% defines moderate-to-severe disease requiring systemic therapy 1
• Patient-reported disability: Assess quality of life impact at every visit 1
• Psoriasis Area and Severity Index (PASI): Score ranges 0-72, with PASI ≥10 indicating moderate-to-severe disease (primarily used in clinical trials) 1

Essential History Components

Disease History

• Onset and duration: Document when psoriasis first appeared and pattern of flares 5
• Previous treatments: Complete drug history including topical agents, phototherapy, and systemic medications with response and adverse effects 5
• Triggering factors: Ask specifically about recent infections, skin trauma, stress, and medication changes 2

Medication Review - Critical for Exacerbation Risk

• Identify psoriasis-worsening drugs: Beta-blockers, NSAIDs, lithium, and antimalarials can precipitate or severely worsen psoriasis 1
• Current medications: Document all medications for drug interaction assessment, especially if systemic therapy is considered 6

Musculoskeletal Screening - Mandatory for All Patients

• Joint symptoms: Ask about morning joint stiffness, joint swelling, and enthesitis (heel or elbow pain) 1
• Screen systematically: 15-30% of psoriasis patients develop psoriatic arthritis; failing to screen leads to irreversible joint damage 1
• Refer to rheumatology: Any suspicion of psoriatic arthritis based on joint symptoms requires specialist evaluation 1

Comorbidity Screening

Cardiovascular and Metabolic Assessment

• Cardiovascular risk factors: Evaluate for hypertension, hyperlipidemia, obesity, diabetes mellitus, and smoking history 1, 2, 4
• Metabolic syndrome: Document BMI, waist circumference, and screen for diabetes 2
• Lifestyle factors: Assess tobacco use, alcohol consumption, and stress levels 2

Mental Health Evaluation

• Depression screening: Psoriasis is associated with increased rates of mental health disorders 1, 4
• Quality of life impact: Document psychosocial burden and functional impairment 3

Other Comorbidities

• Inflammatory bowel disease: Screen for gastrointestinal symptoms 1
• Malignancy risk: Increased risk of lymphoma in psoriasis patients 3

Pretreatment Laboratory Assessment (When Systemic Therapy Considered)

Baseline Laboratory Testing

For all systemic agents 6:

• Complete blood count
• Liver function tests
• Serum creatinine and BUN
• Electrolytes

Additional agent-specific testing:

• PUVA: Eye examination for cataracts 6
• Methotrexate: Pregnancy test in women of childbearing age 6
• Etretinate: Serum lipids, pregnancy test 6
• Cyclosporine: Blood pressure measurement (on at least two occasions), serum magnesium 7

Physical Examination Before Systemic Therapy

• Blood pressure: Measure on at least two occasions before initiating cyclosporine or methotrexate 7
• Liver examination: Clinical assessment for hepatomegaly before methotrexate 6
• Skin lesions: Biopsy any lesions not typical for psoriasis before starting cyclosporine; treat malignant or premalignant changes before immunosuppression 7
• Occult infection: Evaluate for hidden infections before immunosuppressive therapy 7

Indications for Specialist Referral

Dermatology Referral

• Uncertain diagnosis: When clinical presentation is atypical 1
• Moderate-to-severe disease: BSA ≥10% or PASI ≥10 1
• Failure of topical therapy: After 8 weeks of optimized topical treatment 8
• Need for systemic agents or phototherapy: Beyond primary care scope 1

Rheumatology Referral

• Any joint symptoms: Morning stiffness, joint swelling, or enthesitis warrants immediate referral 1

Critical Pitfalls to Avoid

• Never use systemic corticosteroids: They precipitate erythrodermic psoriasis, generalized pustular psoriasis, or very unstable psoriasis upon withdrawal 9
• Screen for pregnancy: Before initiating methotrexate, etretinate, or cyclosporine; methotrexate causes fetal death and congenital anomalies 9, 8
• Assess renal function carefully: Cyclosporine is absolutely contraindicated with abnormal renal function 9
• Evaluate hepatic status: Methotrexate is absolutely contraindicated with significant hepatic damage 9
• Document contraception: Required for all women of childbearing age before systemic therapy 6