Learn more about Humira. Tell your doctor if you have any of the following symptoms of a possible hepatitis B infection:. The most common form of psoriasis is plaque psoriasis, in which patients develop thick, red skin with flaky, silver-white scales. Psoriasis, Cold Sores Most Stigmatized Skin Disorders: Survey. These patches usually appear on the scalp, elbows, knees, face, lower back, hands and feet.