Psoriasis is a chronic skin disorder that produces thick, pink to red, itchy areas of skin covered with white or silvery scales. The rash usually occurs on the scalp, elbows, knees, lower back and genitals, but it can appear anywhere. It can also affect the fingernails.
Psoriasis usually begins in early adulthood but it can start later in life. The rash can heal and come back throughout a person’s life. Psoriasis is not contagious and does not spread from person to person. In most people, the rash is limited to a few patches of skin. In severe cases, it can cover large areas of the body.
Psoriasis starts as small red bumps that grow in size, on top of which scale forms. These surface scales shed easily, but scales below them stick together. When scratched, the lower scales may tear away from the skin, causing pinpoint bleeding. As the rash grows larger, “plaque” lesions can form.
Inverse psoriasis - Psoriasis found in skin folds. This form may present as thin pink plaques without scale.
Pustular psoriasis - Small, pus-filled bumps appear on the usual red patches or plaques.
Sebopsoriasis - Typically located on the face and scalp, this form is made of red bumps and plaques with greasy yellow scale. This is an overlap between psoriasis and seborrheic dermatitis.
The cause of psoriasis is unknown. The condition tends to run in families, so it may be passed on to children by parents. Psoriasis is related to a problem of new skin cells developing too quickly. Normally, skin cells are replaced every 28 to 30 days. In psoriasis, new cells grow and move to the surface of the skin every three to four days. The build up of old cells being replaced by new cells creates the hallmark silvery scales of psoriasis.
No one knows what causes psoriasis outbreaks. How serious and how often outbreaks happen varies with each person. Outbreaks may be triggered by:
As well as the symptoms described above, the rash can be associated with:
If you have a skin rash that does not go away, contact your healthcare provider. He or she can look at the rash to see if it is psoriasis or another skin condition. A dermatologist is a skin care specialist who can make the diagnosis. A small sample of skin may be taken to view under a microscope.
There are many treatments for psoriasis. Your healthcare provider will select a treatment plan depending on the seriousness of the rash, where it is on your body, your age, health, and other factors. For a limited disease affecting only few areas on the skin, topical creams or ointments may be all that is needed. When larger areas are involved, or joint pain indicating arthritis is suspected, additional therapy may be needed.
Newer drugs for treating psoriasis include injectable immune “biologic” therapies as well as small molecule immune modulating pills. They work by blocking the body's immune system from "kick-starting" an autoimmune disease such as psoriasis.
Psoriasis cannot be prevented, but treatment greatly reduces symptoms, even in severe cases.
Here are some things you can do to help improve psoriasis outbreaks and symptoms:
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition. This document was last reviewed on: 05/01/2016