The most common symptoms, plaque psoriasis (psoriasis vulgaris), usually produce:Plaques of red, raised, scaly skin affecting the scalp, elbows, and knees.The plaques may itch or burn. Plaque psoriasis on the elbow. Image courtesy of Hon Pak, MD. The flare-ups can last for weeks or months. Psoriasis can spontaneously resolve only to return later.General characteristics:Plaques: They vary in size (1 centimeter to several centimeters) and may be stable for long periods of time. The shape of the plaque is usually round with irregular borders. Smaller plaques may merge, producing extensive areas of involvement.The skin in these areas, especially when over joints or on the palms or feet, can split and bleed.Plaques sometimes may be surrounded by a halo or ring of blanched skin (Ring of Woronoff). This is especially noticeable after effective treatment has begun and the lesions are resolving.Red color: The color of the affected skin reflects the inflammation present and is caused by increased blood flow.Scale: The scales are silvery white. The thickness of the scales may vary. When the scale is removed, the skin underneath looks smooth, red, and glossy. This shiny skin usually has small areas of pinpoint bleeding (Auspitz sign).Symmetry: Psoriatic plaques tend to appear symmetrically on both sides of the body. For example, psoriasis is usually present on both knees or both elbows. Nail psoriasis. Note the classic pits and yellowish color in the nails. Image courtesy of Hon Pak, MD. Nails: Nail changes are common in psoriasis. The nails may have small indentations or pits. The nails can be discolored and separate from the nail bed at the fingertip. (See Nail Psoriasis.) This may be similar in appearance to fungal nail infections and may actually coexist with, a fungal infection.Psoriasis in children: Plaque psoriasis may look slightly different in children. In children, the plaques are not as thick, and the affected skin is less scaly. Psoriasis may often appear in the diaper region in infancy and in flexural areas in children. The disease more commonly affects the face in children as compared to adults.Other areas: Although the most common body areas affected are the arms, legs, back, and scalp, psoriasis can be found on any body part. Inverse psoriasis can be found on the genitals or buttocks, under the breasts, or under the arms and may not show the scale typically seen in other body areas. These areas can feel especially itchy or have a burning sensation.
