What is psoriasis?

Psoriasis is a chronic skin disorder, which means a skin condition that doesn’t go away. People with psoriasis have thick, pink or red patches of skin covered with white or silvery scales. The thick, scaly patches are called plaques.

Psoriasis usually starts in early adulthood, though it can begin later in life. People of any age, gender or race can get psoriasis. It can get better and worse throughout your life.

What part of the body does psoriasis affect?

The rash can show up anywhere. In most people, it covers only a few patches of skin. In severe cases, the plaques connect and cover a large area of the body. Psoriasis can make you uncomfortable, itchy and self-conscious.

Psoriasis tends to affect the:

  • Elbows and knees.
  • Face, scalp and inside the mouth.
  • Fingernails and toenails.
  • Genitals.
  • Lower back.
  • Palms and feet.

What does psoriasis look like?

At first, you’ll see small red bumps. The bumps grow, and scales form on top. The surface scales might shed easily, but the scales beneath them will stick together. If you scratch the rash, the scales may tear away from the skin, causing bleeding. As the rash continues to grow, lesions (larger areas of damage) can form.

What are other types of psoriasis?

Plaque psoriasis is the most common type. About 80% to 90% of people with psoriasis have plaque psoriasis.

Other, less common types of psoriasis include:

  • Inverse psoriasis appears in skin folds. It may look like thin pink plaques without scale.
  • Guttate psoriasis may appear after a sore throat caused by a streptococcal infection. It looks like small, red, drop-shaped scaly spots in children and young adults.
  • Pustular psoriasis has small, pus-filled bumps on top of the red patches or plaques.
  • Sebopsoriasis typically appears on the face and scalp as red bumps and plaques with greasy yellow scale. This type is a cross between psoriasis and seborrheic dermatitis.

Is psoriasis the same as eczema?

Psoriasis and eczema are two different skin conditions. They differ in where the disease appears on the body, how much it itches and how it looks. Eczema tends to appear more often behind the knees and inside the elbows. Eczema also causes more intense itching than psoriasis. Many people, especially children, can get both eczema and psoriasis.

How common is psoriasis?

Psoriasis affects millions of people. Approximately 3% of the U.S. population has psoriasis.

What causes psoriasis?

Psoriasis is an immune system problem. Your immune response overreacts, causing inflammation, which leads to new skin cells growing too fast.

Typically, new skin cells grow every 28 to 30 days. But in people with psoriasis, new cells grow and move to the skin surface every three to four days. The buildup of new cells replacing old cells creates the silvery scales of psoriasis.

Psoriasis runs in families. There may be a genetic component. Parents may pass it down to their children.

What causes psoriasis outbreaks?

Psoriasis outbreaks differ from person to person. No one knows exactly what causes flare-ups. Common psoriasis triggers may include:

  • Skin injury (cuts, scrapes or surgery).
  • Emotional stress.
  • Streptococcal or other infection that affects the immune system.
  • Certain prescription medications (such as lithium and beta blockers).
  • Cold weather, when people have less exposure to sunlight and humidity and more to hot, dry indoor air.

What are the symptoms of psoriasis?

In addition to red, scaly patches, symptoms of psoriasis include:

  • Itchiness.
  • Cracked, dry skin.
  • Scaly scalp.
  • Skin pain.
  • Nails that are pitted, cracked or crumbly.
  • Joint pain.

Is psoriasis contagious?

The rash is not contagious. You can’t get it from (or give it to) another person.

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