Psoriasis
Psoriasis is a chronic immune-mediated skin disorder characterised by well-demarcated erythematous scaly plaques. It is assosciated with environmental triggers and systemic features including psoriatic arthritis, nail changes and increased cardiometabolic risk.
Station Instructions: Assess this patient presenting with a chronic rash and joint pains.1. Key History‑Taking Points
History of Presenting Complaint:
Skin Lesions:
Onset & course: Age of onset? Relapsing-remitting course?
Progression: Stable, worsening, or episodic?
Distribution: Scalp, elbows, knees, trunk, nails, flexures, genitals?
Symptoms: Itch, pain, bleeding, fissuring, or discomfort?
Triggers: Recent infection (e.g., sore throat), stress, trauma (Koebner phenomenon), medications (β-blockers, lithium, NSAIDs), alcohol, smoking, cold weather.
Remissions: Seasonal variation or improvement with sunlight?
Nail Changes:
Pitting, onycholysis, subungual hyperkeratosis, nail deformity
Joint Symptoms (Psoriatic Arthritis):
Morning stiffness, joint pain/swelling, reduced range of movement
Dactylitis (sausage digits), enthesitis (heel pain), or back stiffness (axial disease)
Impact & Function:
Effect on self-esteem, sleep, daily function, and relationships
Clothing avoidance, psychological distress, anxiety or depression
Past Medical & Family History:
Family history of psoriasis, IBD, metabolic syndrome, or arthritis
History of cardiovascular disease, obesity, diabetes
Previous psoriasis treatments and response (topicals, phototherapy, systemics, biologics)
Medication & Social History:
Current medications (β-blockers, ACE inhibitors, lithium, antimalarials, NSAIDs)
Alcohol intake and smoking
Pregnancy or planning pregnancy (treatment implications)
2. Key Examination Findings
General Inspection:
Symmetrical, well-demarcated, erythematous plaques with silvery scale (extensor surfaces typical)
Distribution: scalp, elbows, knees, umbilicus, lumbosacral area, nails
Auspitz sign (pinpoint bleeding when scale removed), Koebner phenomenon (psoriatic plaques at trauma sites)
Types of Psoriasis:
Chronic plaque (most common)
Guttate (post-streptococcal, drop-like lesions)
Erythrodermic (generalized erythema >90% BSA, systemic symptoms)
Pustular (localized to palms/soles or generalized)
Flexural/inverse (erythematous, non-scaly lesions in skin folds)
Nail Findings:
Pitting, onycholysis, subungual hyperkeratosis, “oil drop” discolouration
Musculoskeletal:
Examine joints (DIPs, PIPs, knees, ankles) for swelling or tenderness
Dactylitis, enthesitis, restricted spinal movement (modified Schober’s test)
Systemic:
Check for metabolic features: obesity, hypertension, central adiposity
Psychological:
Mention DLQI score (impact on quality of life)
3. Specific Investigations
Clinical Diagnosis (usually based on appearance and distribution)
Laboratory Tests:
FBC, U&E, LFTs (baseline for systemic therapy)
CRP/ESR (for psoriatic arthritis or systemic inflammation)
Lipid profile, glucose (metabolic syndrome association)
Throat swab if guttate psoriasis (Streptococcal infections)
HIV screening (in atypical or treatment-resistant cases)
Imaging:
X-rays of affected joints (for psoriatic arthritis — arthritis mutilans – “pencil-in-cup” deformity)
Ultrasound/MRI if early or axial disease suspected
Special Scores:
PASI (Psoriasis Area and Severity Index) — objective severity
DLQI (Dermatology Life Quality Index) — quality of life impact
PGA (Physician Global Assessment) — overall clinical impression
4. Differentials
- Joint Involvement: Rheumatoid Arthritis, Nodal Osteoarthritis, Inflammatory Arthropathis (Reactive Arthritis, Enteropathic Arthropathy, Ankylosing Spondylitis)
- Dermatological Differentials: Seborrheic Dermatitis, Tinea Corporis, Pityriasis Rosea, Discoid Dermatitis
5. Management
Multidisciplinary Approach:
Dermatology, Rheumatology, Psychology, and Primary Care
Stepwise Management (NICE Guidelines):
Topical Therapy (first-line):
Emollients: Soften scale, reduce irritation
Vitamin D analogues (calcipotriol, calcitriol) ± corticosteroids (Dovobet)
Coal tar, dithranol (not commonly used)
Topical steroids: For short-term use on thick plaques or scalp
Phototherapy:
Narrowband UVB for widespread or refractory disease
Systemic Non-biologic Therapy:
Methotrexate: 1st line for moderate-severe psoriasis or psoriatic arthritis (monitor FBC, LFTs, contraceptive advice)
Ciclosporin: Short-term for rapid control or erythrodermic psoriasis
Acitretin: For pustular psoriasis (teratogenic — avoid in pregnancy)
Biologic Therapy:
Indicated for severe disease (PASI ≥10 and DLQI ≥10) following failure of more than one systemic.
TNF-α inhibitors: Adalimumab, Etanercept, Infliximab
IL-17 inhibitors: Secukinumab, Ixekizumab
IL-12/23 inhibitors: Ustekinumab
IL-23 inhibitors: Guselkumab, Risankizumab
Supportive Measures:
Smoking cessation, alcohol reduction, weight management
Psychological support and patient education
Screening for depression and metabolic syndrome
Psoriatic Arthritis Management:
Early rheumatology referral
NSAIDs for pain, DMARDs (methotrexate, sulfasalazine), biologics if resistant
Psoriasis Cheat Sheet
| Domain | Summary |
|---|---|
| Genetics / Aetiology | Chronic immune-mediated skin disorder with strong genetic predisposition (HLA-Cw6); triggered by trauma, infection, stress, drugs. |
| Epidemiology | Affects ~2% of population; bimodal onset (20–30 & 50–60 years); M = F. |
| Pathophysiology | T-cell–mediated inflammation → keratinocyte hyperproliferation and impaired differentiation. |
| History | Chronic scaly rash, itch, nail pitting, arthritis, triggers (stress, infection, drugs). |
| Examination | Well-demarcated erythematous plaques with silvery scale, extensor distribution, nail changes, joint involvement. |
| Differentials | Rheumatoid arthritis, seborrhoeic dermatitis, pityriasis rosacea, tinea corporis. |
| Investigations | Clinical ± biopsy; screen for arthritis and metabolic risk factors. |
| Management | Stepwise: topical → phototherapy → systemic → biologics; lifestyle modification; psychological support. |
| Complications | Psoriatic arthritis, metabolic syndrome, cardiovascular disease, depression, erythroderma. |









































































