Table of Contents Psoriasis Normal structure of skin Epidermis Dermis Hypodermis Evolution of psoriasis and immune factors Sequence in the activation of T lymphocytes contributing to psoriasis MAIN FEATURES OF PSORIASIS Etiology Genetic factors Triggering factors Classification Plaque psoriasis or psoriasis vulgaris Inverse psoriasis Guttate psoriasis Erythrodermic psoriasis Pustular psoriasis