Psoriasis

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Images of Psoriasis

Overview

Psoriasis is a noncontagious, lifelong skin condition that affects about 2–3% of the population of the United States. People with psoriasis have thickened, red, and often scaly patches on their skin. Psoriasis is very likely to run in families, but it can also be triggered by certain situations, such as emotional stress, injury to the skin, infection, as well as taking certain medications. The exact cause of psoriasis is unknown, but it seems to be caused by errors in how the immune system functions.

Who's at risk?

Psoriasis can develop at any age, but it is usually diagnosed in those aged between 15 and 25 years. Thirty percent of people with psoriasis have a family member with psoriasis. The condition affects men and women fairly equally, with women tending to show signs at a younger age than men. As stated above, certain medications can trigger flares of psoriasis. These include beta blockers, NSAIDS (eg, ibuprofen, naproxen), lithium, antimalarial drugs, and oral steroid withdrawal. Approximately 10–30% of people with psoriasis also develop psoriatic arthritis, an inflammatory arthritis that causes painful, swollen joints.

Signs and Symptoms

The typical lesions of psoriasis are red, raised patches that often have a silver or grey scale on top of them. These patches are frequently seen on the elbows, knees, back, buttocks, and scalp, and they are usually seen on both sides of the body. Areas of rubbing or friction are particularly likely to develop psoriasis lesions. Most people also experience itching, but some may not. 

Psoriasis can be graded as:

  • Mild – Few, scattered, small areas of involvement (about two-thirds of people have mild disease)
  • Moderate – More widespread disease affecting larger areas, sometimes affecting the joints
  • Severe – Most of the skin surface is affected, sometimes affecting the joints

The nails may also be affected in psoriasis. There may be tiny pits or indentations, yellow-brown spots, and lifting up of the nail from the finger underneath (onycholysis).

Self-Care Guidelines

Because psoriasis is a lifelong condition for which there is currently no cure, the goal of therapy is to decrease the number of lesions and improve symptoms, such as itching and irritation.

  • Bathe daily to help remove scale and moisten the skin. Avoid harsh soaps; soap substitutes are milder for your skin.
  • Apply moisturizers to all scaly psoriasis patches after any water exposure or bathing. Heavier oil-based moisturizers help to retain water in the skin better than water-based moisturizers.
  • Apply hydrocortisone cream (0.5 or 1%), available over the counter, to help reduce itch and redness.
  • Use products with salicylic acid (shampoos, cleansers, and ointments) to help soften and remove heavy scale.
  • Small doses of natural sunlight may be helpful, such as 10–15 minutes 2 or 3 times a week. Avoid too much sun, however, and protect your healthy skin from sun exposure.

There is also an increased risk of nonmelanoma skin cancer and lymphoma in people with psoriasis. For this reason, monthly skin self-exams and regular visits to your doctor are important.

The National Psoriasis Foundation is a useful resource that has additional information on treating your psoriasis. Their Web site is http://www.psoriasis.org/.

When to Seek Medical Care

See your doctor if you have severe psoriasis or if self-care measures are not helpful.

Treatments Your Physician May Prescribe

There are many prescription-strength treatments that are helpful at controlling psoriasis. For mild or moderate cases, medicines applied directly to the skin (topical treatments) may be prescribed:

  • The mainstay of therapy for psoriasis is topical steroids, either in creams or ointment form. Higher-potency topical steroids are used for the body or scalp, and lower-potency topical steroids are best for the face and skinfold areas. Steroid solutions or liquids can be used on the scalp. Use should be limited to 1–4 weeks at a time because long-term use of steroids can lead to stretch marks (striae) and thinning of the skin.
  • Calcipotriene (Dovonex®) is a vitamin D derivative cream that works as well as steroids, and it is even more effective when combined with topical steroids.
  • Tazarotene (Tazorac®) is a vitamin A-based cream that may be prescribed. Women of childbearing age should be counseled to avoid pregnancy while using tazarotene because this treatment may cause birth defects.
  • Topical immunosuppressants such as tacrolimus (Prograf®) and pimecrolimus (Elidel®) may also be used, but they can cause skin burning and itching and are expensive. These treatments may possibly increase your risk for skin cancer and lymphoma.
  • Coal tar-based therapies and anthralin creams are sometimes used, but they are used less frequently than other treatments because they have an odor, cause skin irritation, and can stain clothing and because neither is any more effective than calcipotriene.

For more extensive psoriasis:

  • If a large percentage of your skin is affected, ultraviolet (UV) light therapies may be considered. These include UVB phototherapy and PUVA (psoralen [a photosensitizer] and UVA therapy). PUVA may increase your risk for non-melanoma skin cancers.
  • Oral medications may be used for extensive psoriasis, including acitretin (made from vitamin A), methotrexate, and cyclosporine. If you are prescribed any of these medicines, you will need to see your doctor regularly so he or she can monitor for possible side effects such as liver and kidney damage.
  • Biologics are the newest medicines to be used for psoriasis. These are proteins that treat psoriasis by blocking certain actions of the immune system. These medications include etanercept (Enbrel®), alefacept (Amevive®), and infliximab (Remicade®). These are very costly and may have serious side effects, including infection, immunosuppression, and cancer.

Trusted Links

MedlinePlus: Psoriasis
National Psoriasis Foundation

References

Bolognia, Jean L., ed. Dermatology, pp.125-146. New York: Mosby, 2003.

Freedberg, Irwin M., ed. Fitzpatrick's Dermatology in General Medicine. 6th ed. pp.407, 1393-1394. New York: McGraw-Hill, 2003.

Luba KM, Stulberg DL. Chronic plaque psoriasis. Am Fam Physician. 2006;73(4):636-644. PMID: 16506705.

Pardasani AG, Feldman SR, Clark AR. Treatment of psoriasis: an algorithm-based approach for primary care physicians. Am Fam Physician. 2000;61(3):725-733, 736. PMID: 10695585.