What are the signs and symptoms of psoriasis? Dry, thick, and raised patches on the skin are the most common sign of psoriasis. These patches are often covered with a silvery-white coating called scale, and they tend to itch. While patches of thickened, dry skin are common, psoriasis can cause many signs and symptoms. What you see and feel tends to vary with the: Type of psoriasis you have Places psoriasis appears on your body Amount of psoriasis you have Types of psoriasis Plaque psoriasis About 80% to 90% of people who have psoriasis develop this type . When plaque psoriasis appears, you may see: Patches of thick raised skin called plaques Scale (a dry, thin, and silvery-white coating) covers some plaques Plaques of different sizes Smaller plaques joining together to form larger plaques Plaques usually form on the scalp, elbows, knees, or lower back, but they can develop anywhere on the skin. It’s common for plaques to itch, but try not to scratch. Scratching can cause the patches