Related Subjects:
|Nikolsky's sign
|Koebner phenomenon
|Psoriatic Arthritis
|Psoriasis
|Anatomy of Skin
π©Ί Psoriasis = chronic, relapsing-remitting inflammatory skin disease.
Characterised by well-demarcated erythematous plaques with silvery scales.
Onset often 10β30 yrs. Significant morbidity due to disfigurement, itching, psychological impact, and risk of psoriatic arthritis.
π About
- Definition: Autoimmune condition with accelerated epidermal turnover β thick scaly plaques.
- Pathophysiology: Keratinocyte maturation shortened from 21β28 days to ~7 days.
- Associated: Psoriatic arthropathy (dactylitis, sacroiliitis, arthritis).
π§ͺ Aetiology
- π« Affects males & females equally.
- 𧬠Genetic predisposition + family history.
- π‘οΈ Immunological: T-cell mediated, chronic inflammation.
- π§± Pathological: keratinocyte proliferation, angiogenesis.
- β‘ Triggers: stress, infections, trauma (Koebner phenomenon), smoking, alcohol, certain drugs (Ξ²-blockers, lithium, NSAIDs, antimalarials).
π Types of Psoriasis
- π₯ Chronic plaque psoriasis: Most common. Extensor plaques with silvery scale.
- π§ Guttate psoriasis: βRaindropβ lesions post-streptococcal infection in young patients.
- π‘ Seborrhoeic psoriasis: Affects nasolabial folds, scalp, retroauricular areas.
- π Flexural (inverse): Shiny red lesions in body folds (axillae, inframammary).
- π₯ Erythrodermic psoriasis: Rare, life-threatening, widespread erythema/scaling β admit.
- π£ Palmar-plantar pustulosis: Sterile pustules on palms/soles.
β‘ Clinical Features
- Red plaques, silvery scales (classically elbows, knees, scalp, lumbosacral area).
- Koebner phenomenon: new lesions at trauma sites.
- Scalp: thick adherent plaques.
- Nails: pitting, onycholysis, βoil dropβ sign.
- Pustules (localized/generalized).
- Erythrodermic psoriasis β urgent review.
π Differential Diagnosis
- Pityriasis rosea vs guttate psoriasis.
- Scalp psoriasis vs seborrhoeic dermatitis (dandruff).
- Chronic eczema vs flexural psoriasis.
π Investigations
- Usually clinical diagnosis.
- Skin biopsy if atypical.
- Screen for comorbidities: metabolic syndrome, diabetes, cardiovascular disease.
π Management
- π©ββοΈ Referral: To dermatology if diagnosis uncertain, extensive disease, occupational impact, face/palm/genital involvement, poor response to 2β3 months of topicals, severe/recalcitrant cases, or suspected psoriatic arthritis β rheumatology.
π§΄ Topical Therapies
- π§ Emollients: 3β4Γ daily. Reduce scaling, itching.
- π§ͺ Vitamin D analogues: Calcipotriol, tacalcitol, calcitriol. Often first-line with/without steroids.
- π Topical corticosteroids: Useful for plaques, scalp, flexures (short-term).
- π€ Coal tar: Anti-inflammatory, odorous but effective. Can combine with salicylic acid for scaling.
- π£ Dithranol: For large plaques. Effective but irritant, stains skin.
- π§΄ Topical retinoids (tazarotene): Mildβmoderate plaque psoriasis.
- π§ Psychological support: Important given stigma and mental health impact.
- π
Follow-up at 6 weeks to assess efficacy/adherence (SIGN 122).
π Special Topical Guidance
- π§΄ Scalp psoriasis: Potent corticosteroid short-term Β± vitamin D analogue (SIGN 121).
- π Flexural psoriasis: Moderate steroids short-term. Alternatives: tacrolimus, vitamin D analogues.
π Phototherapy & Systemic Therapies
- π Phototherapy: Narrow-band UVB for widespread guttate or resistant psoriasis.
- π Oral retinoids: Acitretin for severe disease.
- π‘οΈ Immunosuppressants: Ciclosporin, methotrexate, mycophenolate.
- 𧬠Biologics: Infliximab, etanercept, adalimumab, ustekinumab for severe refractory psoriasis.
- β οΈ Systemic corticosteroids: Reserved for emergency pustular/erythrodermic cases β risk of rebound flare.
π Prognosis
- Chronic, relapsing condition with variable severity.
- Good control possible with modern therapies.
- Important to monitor for psoriatic arthritis + metabolic/cardiovascular comorbidities.
π References