Most cases of psoriasis go through cycles, causing problems for a few weeks or months before easing or stopping.
There are several different types of psoriasis. Normally, people have only one form of psoriasis at a time, although two different types can occur together. One type may change into another type or may become more severe.
Common types of psoriasis
Common types of psoriasis are:
This is the most common form, accounting for 80% of cases. Its symptoms are dry, red skin lesions, known as plaques, that are covered in silver scales. They normally appear on your elbows, knees, scalp and lower back but can appear anywhere on your body. The plaques can be itchy, sore or both. In severe cases, the skin around your joints may crack and bleed.
This normally occurs after a streptococcal throat infection and is more common among children and teenagers. It causes small (less than 1cm or 1/3 inch) drop-shaped sores on your chest, arms, legs and scalp. There is a good chance that guttate psoriasis will disappear completely, but some people go on to develop plaque psoriasis.
This can occur on parts of your scalp or on the whole scalp. It causes red patches of skin covered in thick silvery-white scales. Some people find scalp psoriasis extremely itchy, while others have no discomfort. In extreme cases it can cause hair loss, although this is usually only temporary.
This affects your nails, causing them to develop tiny dents or pits, become discoloured and grow abnormally. Often nails can become loose and separate from your nail bed. In severe cases, your nails may crumble.
Inverse (flexural) psoriasis
This affects areas of the skin that are in folds or creases, such as the armpits, groin and the skin between the buttocks and under the breasts. It can cause large, smooth red patches in some or all of these areas. Inverse psoriasis is made worse by friction and sweating, so it can be particularly uncomfortable in hot weather.
Pustular psoriasis is a rarer type of psoriasis that causes pus-filled blisters (pustules) to appear on your skin. Different types of pustular psoriasis affect different parts of the body.
Generalised pustular psoriasis or von Zumbusch psoriasis
This causes pustules on a wide area of skin, which develop very quickly. The pus consists of white blood cells and is not infected. The pustules may reappear every few days or weeks in cycles. During the start of these cycles, von Zumbusch psoriasis can cause fever, chills, weight loss and fatigue (see erythrodermic psoriasis, below).
Palmoplantar pustular psoriasis
This causes pustules to appear on the palms of your hands and the soles of your feet. The pustules gradually develop into circular brown scaly spots, which then peel off. Pustules may reappear every few days or weeks.
This causes pustules to appear on your fingers and toes. The pustules then burst, leaving bright red areas that may ooze or become scaly. These may lead to painful nail deformities.
Erythrodermic psoriasis is a rare form of psoriasis that affects nearly all the skin on the body. This can cause intense itching or burning. Erythrodermic psoriasis can cause your body to lose proteins and fluid. This can lead to serious illnesses such as infection, dehydration, heart failure, hypothermia and malnutrition.
Last updated: 28 March 2012
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