psoriasis is a skin problem in which you have excessive dry skin. It is a condition in which skin cells build up and form scales and itchy dry patches . Psoriasis is an immune system problem .Although treatment can help but this condition cannot be cured . Chronic cases can last for years . Treatment modalities include topical ointments , oral medication light therapy .Researchers believe both Genetics and environmental factors play a role .The condition is not contagious