What is psoriasis?

Psoriasis (say "sor-eye-ah-sus") is a chronic skin condition that causes thick red marks that look like scales to form. The thick scaling is due to an increase in the number of skin cells. The cause of psoriasis starts with the immune system. T cells, a type of white blood cell, usually protect the body against infection and disease by attacking bacteria and viruses. However, when you have psoriasis, your T cells mistakenly attack your skin cells instead. Your body then produces other immune system responses, leading to swelling and rapid production of skin cells. Psoriasis tends to run in families and it usually appears between the ages of 10 and 45.

People who have psoriasis may experience periods of time without any symptoms. Other times, psoriasis will "flare up" (get worse). Certain things that can cause the psoriasis to get worse include:
  • Infections (such as strep throat and the common cold)
  • Diseases that weaken the immune system
  • Stress
  • Certain medicines (such as beta-blockers for high blood pressure and drugs used to prevent malaria)
  • Skin irritations
  • Cold weather
  • Smoking

What are the symptoms of psoriasis?

The symptoms of psoriasis may include:
  • Red, raised patches of scaly skin
  • Dry, cracked skin (that may also bleed at times)
  • Skin that burns, is itchy or sore
  • Thick, pitted fingernails
  • Pus-filled blisters on the red patches of skin (in more severe cases)
A person who has psoriasis may have red, scaly patches on the skin of the knees and elbows, although psoriasis may occur anywhere on the body (including the scalp, palms of the hands, soles of the feet, mouth and skin on the joints.

Is psoriasis contagious?

No, you cannot catch psoriasis from another person or give it to someone by touching them. You also cannot spread it to other parts of your body.

How is psoriasis treated?

There are various treatments for psoriasis. Your doctor will help you decide which one is best for you. Keeping your skin moisturized with an over-the-counter product is a good first step. Body lotion can help keep skin from getting too dry and cracking. It can also help remove some of the scales. Bathing daily in Epsom salts, Dead Sea salts, bath oil or oatmeal can calm redness and remove scales.

Prescription creams, ointments, lotions and gels (also called topical medicines) that you put on the affected areas are often used to treat psoriasis. To help the medicine, you might apply it and then cover the areas with plastic wrap (such as Saran Wrap). Options include corticosteroids, a type of vitamin D and pine tar. Special shampoos are used for psoriasis on the scalp.

In more severe cases of psoriasis, medicines are taken in pill form. These medicines can cause severe side effect, so your doctor may prescribe these for only a short period of time before returning to another type of treatment.

Sunlight can help psoriasis, but be careful not to stay in the sun too long, since a sunburn can actually make your psoriasis worse. Talk to your doctor about how to safely try sunlight exposure as a psoriasis treatment. Light therapy may be another option for treatment of psoriasis. With this treatment, the affected skin is exposed to controlled forms of artificial sunlight, usually after using Psoralen, a light-sensitizing medicine. This is called "PUVA" treatment. Talk to your doctor about this option.

Will psoriasis go away with treatment?

The scales of psoriasis should improve after you begin treatment. It may take 2 to 6 weeks for the affected areas of your skin to return to a more normal thickness, and the redness may take several months to improve. While psoriasis will typically improve with treatment, it may not ever completely go away. Sometimes, certain scaly spots will get better at the same time that other spots get worse.

After you've been using a certain type of medicine for awhile, your psoriasis may "get used to" the treatment. If this happens, your medicine may not be as effective as it once was. Your doctor may change your medicine. Sometimes you may need a stronger dose of medicine. Talk to your doctor if your psoriasis doesn't seem to be getting better with treatment.

More Information

For more information talk to your doctor.

Other Organizations


Written by editorial staff.

American Academy of Family Physicians

Reviewed/Updated: 10/08
Created: 07/95