Plaque psoriasis is the most common presentation of psoriasis. It presents as small to large, well demarcated, red, scaly and thickened areas of skin. It most likely to affect elbows, knees, and lower back but may arise on any part of the body. The disease is psoriasis vulgaris (EFO_1001494, an Experimental Factor Ontology term). Also known as: plaque psoriasis.