Psoriasis

• Psoriasis affects 1.5% to 2% of the population in Western countries but has worldwide occurrence.
• A chronic disorder with polygenic predisposition and triggering environmental factors such as bacterial infection, trauma, or drugs.
• Several clinical expressions. Typical lesions are chronic, recurring, scaly papules, and plaques. Pustular eruptions and erythroderma occur.
• Clinical presentation varies among individuals, from those with only a few localized plaques to those with generalized skin involvement.
• Psoriatic erythroderma is psoriasis involving the entire skin.
• Psoriatic arthritis occurs in 7% to 25% of psoriasis patients.

Classification
• Psoriasis vulgaris
  • Acute guttate
  • Chronic stable plaque
  • Palmoplantar
  • Inverse
• Psoriatic erythroderma
• Pustular psoriasis
  • Pustular psoriasis of von Zumbusch
  • Palmoplantar pustulosis
  • Acrodermatitis continua