What is psoriasis?

• Psoriasis is a red and scaly chronic skin condition of unknown cause.

Psoriasis on the elbows

Who gets it?

• About 30% of people with psoriasis have a family history of the condition.

• It affects 1% to 2% of the world's population.

• Psoriasis most frequently begins in the second or third decade of life, but it can first be seen in infants or in elderly persons.

What causes it?

• The exact cause is unknown; however, we do know that psoriatic lesions (spots) result from an increase in epidermal cell division.

Psoriasis on the buttocks

What does it look like, and where on the body does psoriasis occur?

• Thickened, reddened, silvery or whitish, scaly patches can vary from only a few small bumps known as papules to larger plaques that cover large areas of the body.

• Psoriasis tends to be remarkably symmetric. (It tends to look almost the same on both sides of the body.)

• Fortunately, it usually spares the face.

• Psoriasis is most commonly located on the:

  • Large joints: elbows, knees, and knuckles.

  • Palms and soles.

  • Body folds: the underarms, under the breasts, the anus and genital region, and the groin. This body fold type of psoriasis is referred to as inverse psoriasis.

  • Trunk. Lesions may be small, guttate (teardrop-shaped), or large plaques.

  • Scalp and ears.

  • Nails. Involvement of nails is very common in patients with psoriasis.

Psoriasis on the scalp

What are its symptoms?

• Psoriasis generally is symptom-free but can become quite itchy and uncomfortable, particularly during acute flare-ups or when it involves the scalp or skin fold regions.

  • A person who has psoriasis is mainly concerned about the appearance of his or her skin.

  • Psoriatic arthritis occurs in about 7% of patients who have psoriasis.

Psoriasis affecting the nails

What makes it worse?

• Emotional stress, such as anxiety and depression, is believed to worsen psoriasis.

• Certain drugs and excess alcohol may also play roles.

What is the usual course of psoriasis?

• Psoriasis has an unpredictable, waxing and waning course. It has no known cure.

• In its mildest forms, psoriasis is an incidental finding. It may consist of nail pitting or mildly red, scaly patches on the elbows or knees.

• During episodes of physical illness or pregnancy, psoriasis may worsen or suddenly clear.

• The condition tends to improve during the summer and worsen during the colder times of the year. This fluctuation is probably a result of the positive influence of sunlight on psoriasis.

How is it diagnosed?

• Dermatologists can usually easily recognize it by simply examining the skin.

• Other helpful diagnostic features include family history of psoriasis.

• If necessary, other tests, such as a skin biopsy or fungal examinations, can be performed to rule out other conditions.

How is it treated?

• Topical corticosteroids. The use of a very potent topical steroid applied for a limited period, followed by a less-potent topical steroid for maintenance, has become a popular method for treating psoriasis.

• Topical vitamin D

  • Dovonex (calcipotriene ointment, cream, and solution) is often used in combination with topical steroids.

  • Taclonex combines vitamin D and a topical steroid.

• Topical immunomodulators such as Protopic ointment and Elidel cream are sometimes used to treat inverse psoriasis.

• Other topical treatments. Topical retinoids and topical tar preparations are less often used.

• Ultraviolet light therapy

  • Natural sunlight sometimes slows the growth of psoriasis. People with psoriasis all over their bodies may be treated with light boxes that expose most of their body to ultraviolet light.

  • Ultraviolet light therapy plus oral treatments is used when a person who has psoriasis is not responding to topical therapies or ultraviolet light treatment alone.

• Diets. Special diets do not seem to help in any way.

• Newer approaches to psoriasis therapy. There are many new biologic agents that are currently available for the treatment of psoriasis and psoriatic arthritis.

The National Psoriasis Foundation provides information about the latest treatments for psoriasis, educational pamphlets, and information about self-help and discussion groups (800-723-9166).