What is psoriasis?
Psoriasis is a common skin disorder that produces thick, pink to red, itchy patches of skin covered with silvery scales. In black African-Americans, the rash may be the same color as the skin. The rash usually occurs on the scalp, elbows, knees, lower back and genitals and in the same place on both sides of the body. It can also occur in the fingernails. Psoriasis does not spread from person to person.
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. In most people, the rash is limited to a few patches of skin. In severe cases, it can cover large areas of the body.
How does the rash start?
Psoriasis starts as small red bumps. The bumps grow in size and scales form on top. These surface scales shed easily, but scales below them stick together. When scratched, the lower scales tear away from the skin, causing bleeding. As the rash grows large lesions can form. The silvery scales on top of these lesions are sometimes called "plaques."
What are the symptoms of psoriasis?
As well as the symptoms described above, the rash may produce:
- Intense itching
- Dry and cracking skin
- Skin swelling
- Skin pain
- Pitted, cracked, or crumbly nails
- Loose nails
Less common forms of psoriasis
Inverse psoriasis
Psoriasis under the armpit and breast and in skin folds around the groin, buttocks and genitals.
Guttate psoriasis
Small, red, drop-shaped, scaly spots in children and young adults that often appear after a sore throat caused by a streptococcal infection.
Pustular psoriasis
Small pus-filled bumps appear on the usual red patches or plaques
How can I know if I have psoriasis?
If you have a skin rash that won’t go away, contact your health care provider. He or she can look at the rash to see if it is psoriasis or another skin condition. Rarely, a small sample of skin is taken to view under a microscope.
What causes psoriasis?
The cause of psoriasis is unknown. The condition tends to run in families, so it may be passed on to children by parents.
Psoriasis causes new skin cells to develop 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.
What causes psoriasis outbreaks?
No one knows what causes psoriasis outbreaks. How serious and how often outbreaks happen varies with each person. Outbreaks may be triggered by:
- Skin injury (Cuts, scrapes or surgery that requires cutting of the skin, for example.)
- Emotional stress
- Streptococcal and other infections
- Cold, cloudy weather
- Certain prescription medicines
Can psoriasis be cured?
Psoriasis cannot be cured, but treatment greatly reduces symptoms, even in severe cases.
How is psoriasis treated?
There are many treatments for psoriasis. Some treatments slow the production of new skin cells while others relieve itching and dry skin. Inflammation in the skin is an important part of psoriasis and many treatments reduce inflammation. Your health care 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.
Common treatments include:
- Steroid creams
- Moisturizers (to relieve dry skin)
- Anthralin (a medicine that slows skin cell production)
- Coal-tar (common for scalp psoriasis; may also be used with light therapy for severe cases; available in lotions, shampoos and bath solutions)
- Vitamin D3 ointment, called Dovonex, a special form ordered by your health care provider, (Vitamin D in foods and vitamin pills has no effect on psoriasis.)
Treatment for severe cases:
- Light therapy (ultraviolet light at specific wavelengths decreases inflammation in the skin and helps to slow the production of skin cells)
- PUVA (treatment that combines a medicine called "psoralen" with exposure to a special form of ultraviolet light)
- Retinoids (a special form of Vitamin A-related drugs; Retinoids can cause serious side effects, including birth defects. Brand names of retinoids are Soriatane and Tazorac.) Vitamin A in foods and vitamin pills has no effect on psoriasis.
- Cyclosporine (a very effective capsule reserved for severe psoriasis because it can cause high blood pressure and damage to kidneys).
- Newer drugs for treating psoriasis include Amevive, Raptiva, and Enbrel. All three are given by injection and belong to a group of drugs known as biologic therapies. They work by blocking the body's immune system from "kick-starting" an autoimmune disease such as psoriasis.
Tips for improving psoriasis in addition to prescription medicines:
- Use moisturizer.
- Avoid using harsh soaps.
- Apply oil or moisturizer after bathing.
- Expose psoriasis to moderate sunlight.
- Use a tar shampoo every other night.
Where can I learn more?
National Psoriasis Foundation
800.723.9166
American Academy of Dermatology
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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 health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 11/4/2005
