psoriasis psoriasis vulgaris true MedDRA:10050576 ICD10:L40.0 Dani Welter SNOMEDCT:200975007 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. plaque psoriasis