Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
An individual with plaque psoriasis usually has patches of red, raised, scaly areas on the skin that may itch or burn. The patches are usually found on the knees, elbows, trunk, or scalp. Approximately
nine out of 10 people with psoriasis have plaque psoriasis.
Plaque psoriasis on the elbow. Image courtesy of Hon Pak, MD.
The flare-ups can last for weeks or months. The psoriasis goes away for a time and then returns (chronic).
General characteristics of the scaly skin of the most common type of psoriasis are as follows:
Plaques: The plaque areas on the skin are elevated. The plaque areas vary in size (1
centimeter to several centimeters) and may range from a few to many at any given time on the skin. The shape of the plaque is usually oval but can be irregular in shape. Smaller plaque areas may merge with other areas and form a large affected area.
Plaque psoriasis. Image courtesy of Hon Pak, MD.
The skin in these areas, especially when over joints or on the palms or feet, can split and bleed.
Plaque psoriasis with fissures, which are splits in the skin. Fissures usually occur where the skin bends (joints). The skin may bleed and is more susceptible to infection. Image courtesy of Hon Pak, MD.
Plaques sometimes have an area around them that looks like a halo or ring (Ring of Woronoff).
Red color: The color of the affected skin is very
distinctive. The rich, full red color is salmon colored. Sometimes the
skin can have a blue tint when the psoriasis is on the legs.
Scale: The scales are dry, thin, and
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 that bleed (Auspitz sign).
Symmetry: Psoriatic plaques tend to appear on both sides of the body in the same places. For example, the psoriasis is usually on both knees or both elbows at the same time.
Other general symptoms of psoriasis are as follows:
Scalp: The scalp can have dry, scaly skin or crusted plaque areas. Sometimes psoriasis of the scalp is confused with seborrheic dermatitis. In seborrheic psoriasis, the scales are greasy looking, not dry.
Psoriasis of the scalp. Image courtesy of Hon Pak, MD.
Nails: Nail changes are commonly observed in those with plaque psoriasis. The nails may have small indentations, ridges, or pits in them. The nails can be discolored or separate from the nail bed. (See Nail Psoriasis.)
Nail psoriasis. Note the classic pits and yellowish color in the nails. Image courtesy of Hon Pak, MD.
Droplets on skin: Sometimes, the skin is red and looks like it has little drops on it. This may be guttate psoriasis. (See Types of Psoriasis - Guttate.)
Guttate psoriasis. Red drop-like lesions are found on the skin. This type of psoriasis usually occurs after a streptococcal (bacterial) infection. Image courtesy of Hon Pak, MD.
Pus on patches: Sometimes, the patches of dry, scaly skin can crack and have pus on top of them. This may be pustular psoriasis. (See Types of Psoriasis - Pustular.)
Pustular psoriasis. Image courtesy of Hon Pak, MD.
Psoriasis in children: Plaque psoriasis looks slightly different in children compared to adults. 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, leg, back, and scalp, psoriasis can be found on any body part. Psoriasis can be found on the genitals or buttocks, under the breasts, or under the arms. These areas can feel especially itchy or burning.
Psoriasis on the palms. Image courtesy of Hon Pak, MD.