Summary

• Chronic inflammatory skin disease characterised by extensive erythematous, circumscribed scaly papules, and plaques.
• Runs a variable course and seldom completely subsides. Severity is aggravated by genetic, infectious, emotional, and environmental factors.
• Lesions are red, inflamed, silvery-white scaly, and circumscribed papules and plaques on elbows, knees, extensor limbs, and scalp. Psoriatic nails have a pitted surface and/or hypertrophic (subungual) changes.
• Skin biopsy may aid diagnosis.
• Mild and limited psoriasis is treated with topical corticosteroids, tar preparations, vitamin D, and retinoids.
• Moderate to severe and/or extensive psoriasis may require phototherapy, oral retinoids, methotrexate, ciclosporin, systemic corticosteroids, or biological agents.