Looking at Psoriasis

Psoriasis 

1. Definition

• Psoriasis is a chronic autoimmune skin condition.
• It causes rapid skin cell turnover, leading to thickened, scaly patches that can be itchy, painful, or inflamed.
• Unlike eczema, which is largely barrier dysfunction + allergic hypersensitivity, psoriasis is more of an immune-driven overproduction process.

2. Causes & Mechanisms

• Autoimmune Reaction: The immune system mistakenly activates T-cells, which trigger skin cells (keratinocytes) to multiply up to 10× faster than normal.
• Genetic Factors: Strong hereditary link; certain gene variants increase risk.
• Immune Pathways: Overactivation of Th1 and Th17 cells, releasing inflammatory cytokines like TNF-α, IL-17, and IL-23.
• Environmental Triggers: Stress, infections (especially strep throat), cold weather, skin injury (Koebner phenomenon), alcohol, smoking, certain medications.

3. Types of Psoriasis

1. Plaque Psoriasis (Psoriasis vulgaris): Most common, with raised red patches covered by silvery-white scales.
2. Guttate Psoriasis: Small, drop-like lesions, often triggered by infections.
3. Inverse Psoriasis: Affects skin folds (armpits, groin, under breasts).
4. Pustular Psoriasis: White pustules surrounded by red skin.
5. Erythrodermic Psoriasis: Severe, widespread redness, scaling, and systemic illness (can be life-threatening).

4. Symptoms

• Raised red patches with thick, silvery scale.
• Itching, burning, or soreness.
• Nail changes (pitting, ridging, separation from nail bed).
• Psoriatic arthritis (joint pain, stiffness, swelling) in up to 30% of patients.