These are also known as skin plaques. Plaques are flat or raised areas or groups of small bumps typically more than 10 millimeters (0.4 inch) in diameter. It can appear like few small spots that look similar to dandruff or it can be huge eruptions that cover larger parts of the body, like the forearms. Plaque can cause itching, burning and swelling and are most commonly associated with psoriasis. It appears most commonly on the elbows, knees, scalp and lower back.
