Psoriasis is a chronic, autoimmune disease that causes scaly patches on the skin called plaques when immune system signals speed up skin cell growth. It can affect the nails and has different classifications including plaque, pustular, guttate, and forms linked to arthritis. Psoriasis reduces quality of life similarly to other chronic conditions. Genetics and immune system issues contribute to its cause. Diagnosis is usually based on visual inspection, though biopsies can confirm. Management includes topical treatments, phototherapy, systemic drugs, and alternative therapies. Psoriasis has no cure but available treatments can control symptoms.