Psoriasis

Definition

• A chronic inflammatory skin disorder driven by immune overactivity, resulting in accelerated skin turnover(hyperproliferation of keratinocytes) and characteristic scaling, red plaques, pruritus, and/or pain.

Types

1. Plaque Psoriasis (Psoriasis Vulgaris)

   • Most common form

   • Raised, red patches with silvery-white scales

   • Typically on scalp, elbows, knees, lower back

2. Guttate Psoriasis

   • “Drop-shaped” lesions, often triggered by strep infections

   • More common in children/young adults

3. Inverse Psoriasis

   • Smooth, red patches in skin folds (e.g. armpits, groin, under breasts)

   • Minimal scaling due to friction/moisture in folds

4. Pustular Psoriasis

   • White pustules on a red base; can be localised (palms/soles) or generalised (von Zumbusch)

5. Erythrodermic Psoriasis

   • Rare, severe form with widespread redness and scaling over most of the body

   • Can be life-threatening (thermoregulation/fluid loss)

Aetiology & Triggers

• Genetic Predisposition: Strong familial tendency

• Stress, infections (e.g. strep throat)

• Skin Injury (Koebner phenomenon)

• Cold weather, dryness

• Smoking, alcohol overuse

• Medications: Beta-blockers, antimalarials, lithium, NSAIDs, some biologics

Symptoms

• Red patches with silvery-white scales

• Dry, cracked skin ± bleeding

• Itching, burning, soreness

• Nail changes: Thickening, ridging, pitting (psoriatic onychodystrophy)

• Psoriatic Arthritis: Swollen, stiff joints (5–30% of psoriasis patients)

Management

Topical Therapies

• Corticosteroids: First-line for mild, localised plaques

• Vitamin D Analogues (e.g., calcipotriol): Reduce keratinocyte proliferation

• Coal Tar preparations: Anti-inflammatory, keratolytic properties

• Other: Topical retinoids (tazarotene), salicylic acid for scalp

Phototherapy

• Controlled UVB or PUVA to reduce plaques

• Monitor for photodamage, possible skin cancer risk with prolonged therapy

Systemic (Severe Psoriasis)

• Methotrexate, Cyclosporine, Acitretin: Traditional systemic agents

• Biologic Therapies (TNF-alpha inhibitors, IL-17/IL-23 inhibitors, etc.): For moderate–severe, especially if refractory to conventional agents

Lifestyle & Self-Care

• Regular Moisturising: Prevent dryness, cracking

• Avoid Known Triggers (e.g. smoking, excess alcohol, stress)

• Moderate Sun Exposure: Often beneficial (avoid sunburn)

• Healthy Diet & Weight Management: Obesity can worsen psoriasis and reduce response to therapy

Notes

• Psoriatic Arthritis requires early rheumatology referral to prevent joint damage.

• Patients may experience emotional distress or stigma; psychological support is valuable.

• Comorbidities (metabolic syndrome, depression) are more common in psoriasis; screen accordingly.