Psoriasis is a common skin condition that causes skin redness and irritation. Most people with psoriasis have thick, red skin with flaky, silver-white patches called scales.

Psoriasis may affect you at any age, but it usually begins between the ages of 15 and 35. You can't spread this disorder to others, but it does seem to be passed down through families. We think it probably occurs when your immune system mistakes healthy cells for dangerous substances.

Skin cells grow deep in your skin, normally rising to the surface about once a month. But, in people with psoriasis, this process occurs too fast, usually happening in only about 2 weeks, and dead skin cells build up on your skin's surface. Many factors can trigger psoriasis, or make it more difficult to treat, including bacterial or viral infections, dry air or skin, injuries to your skin, some medications, stress, too much or too little sunlight, and even too much alcohol. In general, psoriasis may be very bad in people who have a weakened immune system.

Psoriasis can appear suddenly or it can appear slowly. Often, it goes away and then flares up again, time after time. If you have psoriasis, you'll probably have irritated patches of skin on your body, often on your elbows and knees. But it can show up anywhere on your body, even your scalp.

The skin patches may be itchy, dry and covered with silver, flaky scales. They may be pink in color and raised and thick.

So, what do you do about psoriasis?

Well, your doctor will need to look at your skin to make a diagnosis. Sometimes the doctor will take a skin sample, or a biopsy, to rule out other possible problems.

Your treatment will focus on controlling your symptoms and preventing infections. In general, you have three options: topical medications like lotions or creams, pills or injections that affect your whole body, and therapy that uses light to treat psoriasis. But most people tend to use creams or ointments they place directly on their skin.

Psoriasis is a life-long condition you can control with treatment. It may go away for a long time and then suddenly return. Fortunately, with the right treatment, it usually does not affect your general physical health.