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Psoriasis – PLAB 2 High-Yield Clinical Guide

Updated: 6 days ago


1. Overview

  • Chronic, relapsing–remitting immune-mediated inflammatory skin condition.

  • Non-infectious; affects ~2% of UK population.

  • Driven by genetic predisposition + environmental triggers.

  • Impacts skin, nails, joints, eyes and can be associated with systemic complications.



2. Typical Presentations


History

  • Skin lesions: Onset, progression, itch, scale, redness, bleeding after scratching (Auspitz sign).

  • Pattern: Chronic plaques, guttate (post-strep), pustular, inverse.

  • Triggers: Infection, trauma (Koebner phenomenon), stress, drugs (β-blockers, lithium, antimalarials, NSAIDs).

  • Systemic symptoms: Joint pain/swelling (psoriatic arthritis), fatigue, eye symptoms (uveitis).

  • Impact: Quality of life, embarrassment, work, social life.


Examination

  • Skin: Well-demarcated erythematous plaques with silvery-white scale, symmetrical distribution (extensor surfaces, scalp, lumbosacral, periumbilical).

  • Nails: Pitting, onycholysis, subungual hyperkeratosis.

  • Joints: Asymmetrical oligoarthritis most common.

  • Special signs:

    • Auspitz sign – pinpoint bleeding after scale removal.

    • Koebner phenomenon – lesions at trauma sites.

    • Woronoff ring – pale halo around healing plaques.


3. Progression

  • Variable course: Some have mild, intermittent disease; others have chronic, widespread, and treatment-resistant psoriasis.

  • Risk of progression:

    • Localised → generalised disease

    • Cutaneous → joint involvement

  • Flares triggered by stress, infection, medication changes (especially rapid corticosteroid withdrawal).



4. Complications


Local

  • Skin infection

  • Erythroderma (>90% BSA redness/scaling; dermatology emergency)

  • Generalised pustular psoriasis (systemic illness, urgent referral)


Systemic

  • Psoriatic arthritis (up to 30%)

  • Eye: anterior uveitis

  • Metabolic syndrome, obesity, NAFLD

  • Cardiovascular disease: ↑ risk MI, stroke, VTE

  • Psychological: depression, anxiety, low self-esteem

  • IBD association (esp. Crohn’s)



5. PLAB 2 – Management Approach


A. Core principles

  • Reassure: psoriasis is not infectious.

  • Aim: symptom control + flare prevention.

  • Involve patient in decision-making; check understanding.


B. NICE-Aligned Management Ladder (Adults)

Baseline for all:

  • Daily emollients – soften skin, reduce itch, help active treatments work better.

  • Manage triggers (medication review, infection treatment, stress management, smoking/alcohol reduction).


First-line (Trunk/Limbs – Mild/Moderate)

Morning – Potent steroid (e.g., betamethasone valerate 0.1%)Evening – Vitamin D analogue (e.g., calcipotriol)


Directions to patient:

  1. Wash hands before and after applying.

  2. Apply emollient first to all affected and dry areas; wait at least 30 minutes before applying active treatments.

  3. Steroid cream/ointment (morning):

    • Apply a thin layer directly to plaques only, using fingertip units (one fingertip length covers ~2 adult hand areas).

    • Gently rub in until absorbed.

    • Avoid face, skin folds, and genitals unless told otherwise.

  4. Vitamin D cream/ointment (evening):

    • Apply to same plaques, thin layer, rub in gently.

    • Do not apply at the same time as steroid — space by several hours.

  5. Treatment length:

    • Potent steroid for up to 8 weeks/site, then take a 4-week steroid-free break.

    • Vitamin D analogue can be continued longer for maintenance.


Second-line

  • If not controlled after 8 weeks: Vitamin D analogue twice daily (no steroid) for 8 more weeks.


Third-line

  • Potent steroid twice daily for 4 weeks OR coal tar preparation once/twice daily.

  • Short-contact dithranol only if trained nurse/specialist support.


Scalp Psoriasis


First step: Potent steroid scalp lotion/gel once daily.Directions:

  • Part hair, apply directly to scalp lesions, massage in gently.

  • Leave on; wash hair as normal later in the day or next morning.

  • Use keratolytic oils (e.g., coconut oil, salicylic acid) overnight to soften scale before shampooing.


Face/Flexures/Genitals (Inverse psoriasis)

  • Mild/moderate steroid (e.g., hydrocortisone 1% or clobetasone butyrate 0.05%) once daily for 1–2 weeks only.

  • Consider calcineurin inhibitors (tacrolimus, pimecrolimus) for maintenance.



6. Follow-Up

  • Review at 4 weeks → assess % improvement, symptoms, and side effects.

  • Adjust treatment up or down per ladder.

  • Once clear/nearly clear → stop steroid, continue vitamin D analogue for maintenance.



7. Lifestyle & Self-Management Advice

  • Stop smoking, limit alcohol, maintain healthy weight, manage stress.

  • Avoid scratching; moisturise frequently.

  • Treat strep throat promptly to reduce guttate flares.

  • Avoid medicines that may worsen psoriasis unless essential (review with GP).

  • Keep up regular cardiovascular risk checks (every 5 years or earlier if severe).



8. Red Flags – Seek Urgent Help

  • Rapidly spreading redness or pustules, fever, or feeling unwell (erythroderma/generalised pustular psoriasis).

  • New joint pain, swelling, or eye redness/pain (possible psoriatic arthritis or uveitis).



9. Advice & Education for PLAB 2 Counselling Stations

  • Lifestyle: Stop smoking, limit alcohol, maintain healthy weight, manage stress.

  • Steroid safety:

    • Potent: ≤8 weeks/site, then 4-week break.

    • Very potent: ≤4 weeks/site, then 4-week break.

    • Avoid face/flexures/genitals unless directed.

  • Application: Apply thin layer to affected skin, rub in gently, wash hands after.

  • Maintenance: Vitamin D analogue for ongoing control between steroid courses.

  • Follow-up: Review at 4 weeks; earlier if worsening or systemic symptoms.

  • Seek urgent help if:

    • Skin becomes red all over, pustules spread, you feel feverish/unwell.

    • New joint pain, swelling, or eye redness/pain.



10. PLAB 2 Communication Tips

  • Use layman’s terms for skin findings (“red patches with dry, silvery skin” instead of “erythematous plaques with scale”).

  • Check patient’s emotional wellbeing; acknowledge impact on confidence and daily life.

  • Offer printed information (NHS psoriasis leaflets, Psoriasis Association contacts).


📚 References

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