Psoriasis (cont.)

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What causes psoriasis?

The exact cause remains unknown. There may be a combination of factors, including genetic predisposition and environmental factors. It is common for psoriasis to be found in members of the same family. The immune system is thought to play a major role. Despite research over the past 30 years looking at many triggers, the "master switch" that turns on psoriasis is still a mystery.

What does psoriasis look like? What are psoriasis symptoms and signs?

Psoriasis appears as red or pink areas of thickened, raised, and scaling skin. It classically affects areas over the elbows, knees, and scalp. Although any body area may be involved, it tends to be more common in areas of trauma, scratching, or abrasions.

Psoriasis may vary in appearance. It often appears as small flattened scaly bumps and larger thick plaques of raised skin.

There are several different types of psoriasis, including psoriasis vulgaris (common type), guttate psoriasis (small, drop-like spots), inverse psoriasis (in the folds like of the underarms, navel, groin, and buttocks), and pustular psoriasis (small pus-filled yellowish blisters). When the palms and the soles are involved, this is known as palmoplantar psoriasis.

Sometimes pulling off one of these small dry white flakes of skin causes a tiny blood spot on the skin. This is medically referred to as a special diagnostic sign in psoriasis called the Auspitz sign.

Genital lesions, especially on the head of the penis, are common. Psoriasis in moist areas like the navel or the area between the buttocks (intergluteal folds) may look like flat red patches. This may be confused with other skin conditions like fungal infections, yeast infections, skin irritation, or bacterial infections.

Finger and toenails often exhibit small pits (pinpoint depressions) and/or larger yellowish-brown separations of the nail bed called "oil spots." Nail psoriasis may be confused with and incorrectly diagnosed as a fungal nail infection.

Scalp psoriasis may look like severe dandruff with dry flakes and red areas of skin. It may be difficult to differentiate between scalp psoriasis and seborrhea dermatitis when only the scalp is involved. However, the treatment is often very similar for both conditions.

Medically Reviewed by a Doctor on 5/2/2014

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