Diseases & Conditions

Psoriasis: An Overview

What is psoriasis?

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. Though it can run in families, 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.

How does the rash start?

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.

What are the symptoms of psoriasis?

As well as the symptoms described above, the rash can be associated with:

  • Itching
  • Dry and cracked skin
  • Scaly scalp
  • Skin pain
  • Pitted, cracked thick or crumbly nails
  • Joint pain

What are the less common forms of psoriasis?

  • Inverse psoriasis: Psoriasis found in skin folds, such as the underarm area, groin, buttock, breast, and genital folds. This form may present as thin pink plaques without scale.
  • 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.
  • 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.

How can I know if I have psoriasis?

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.

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 relates 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 buildup 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 (for example, cuts, scrapes, or surgery)
  • Emotional stress
  • Streptococcal and other infections
  • Certain prescription medicines (for example, lithium, and certain beta blockers)

How is psoriasis treated?

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.

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
  • Vitamin A or retinoid creams

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).
  • Methotrexate (a medicine taken by the mouth; methotrexate can cause liver disease, so its use is limited to severe cases and is carefully watched with blood tests and sometimes liver biopsies).
  • Retinoids (a special form of vitamin A-related drugs, retinoids can cause serious side effects, including birth defects)
  • 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 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.

Can psoriasis be cured?

Psoriasis cannot be cured, but treatment greatly reduces symptoms, even in severe cases.

Tips for improving psoriasis in addition to prescription medicines:

  • Use moisturizer
  • Avoid using harsh soaps
  • Apply oil or moisturizer after bathing
  • Use a tar or salicylic acid shampoo for scale on scalp

© Copyright 2017 Cleveland Clinic Abu Dhabi. All rights reserved.

This information is provided by Cleveland Clinic Abu Dhabi, part of Mubadala Healthcare, 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.

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