Treatments for Psoriasis

Doctors generally treat psoriasis in a "1-2-3" step approach, based on:

• the severity of the disease

• how much skin is involved

• the type of psoriasis

• how the individual responds to initial treatments.

In step 1, medicines are applied to the skin (topical treatment). Step 2 focuses on light treatments (phototherapy). Step 3 involves taking medicines internally, by mouth (orally) or injection.

Over time, affected skin can become resistant to certain treatments. Also, a treatment that works very well in one person may have little effect in another. Thus, doctors commonly use a trial-and-error approach to find a treatment that works. They may switch treatments periodically (for example, every 12 to 24 months) as needed. A combination of therapies often can be more effective than a single therapy.

Newer, more effective drug treatments for both psoriasis and psoriatic arthritis are becoming available. Recent research has led to a better understanding of how the immune system triggers these diseases. In January 2002, the Food and Drug Administration (FDA) approved the new drug etanercept (Enbrel) to treat psoriatic arthritis. Etanercept had previously been approved for treatment of rheumatoid arthritis (RA). While not yet approved by the FDA to treat psoriasis, some studies have shown that the drug may be helpful to many people with psoriasis. Etanercept and similar drugs, such as infliximab (Remicade), block the action of a cytokine called tumor necrosis factor alpha (TNF-alpha). Cytokines help set off the inflammation seen in psoriasis. Other drugs in development act by blocking the inflammatory process in other ways. While these new drugs have exciting potential for persons with psoriasis, they may also have serious side effects.

Topical treatment for psoriasis

Treatments applied directly to the skin sometimes work well to clear psoriasis.

• Corticosteroids are available in different strengths and are usually applied twice a day. Short-term treatment often can improve but not completely clear psoriasis. Long-term use or overuse of stronger products can worsen the psoriasis, thin the skin, and lead to internal side effects and resistance to the treatment's benefits.

• Calcipotriene is a synthetic form of vitamin D3. (It is not the same as vitamin D supplements.) Applying calcipotriene ointment twice a day controls excessive production of skin cells. It is not recommended for the face or genitals.

• Coal tar can be applied to the skin, used in a bath solution, or used on the scalp as a shampoo. It is available in different strengths. It has a number of drawbacks including being messy, having a strong odor, and causing staining of skin and clothing.

• Anthralin is used as an ointment, cream, or paste to treat psoriasis lesions. However, this treatment often fails to adequately clear lesions and has other drawbacks.

• Tazarotene is a topical retinoid. It is a fast-drying, clear gel applied to the skin. It does not act as quickly as topical steroids, but it has fewer side effects. Women of childbearing age should use birth control when using it.

• Salicylic acid can help remove scales. It is most effective when combined with topical steroids, anthralin, or coal tar.

• Bath solutions and moisturizers help some people.

Phototherapy for psoriasis

Ultraviolet (UV) light from the sun causes activated T cells in the skin to die (apoptosis). This reduces inflammation and slows the overgrowth of skin cells that causes scaling. Daily, short, nonburning exposure to sunlight clears or improves psoriasis in many people. More controlled forms of artificial light treatment include:

• Ultraviolet B (UVB) phototherapy. Some artificial sources of UVB light are similar to sunlight. Narrowband UVB treatment is superior to broadband UVB, but burns can be more severe and last longer than with broadband UVB. Some doctors will start with UVB treatments instead of topical agents. UVB phototherapy can also help treat widespread psoriasis and lesions that resist topical treatment. You can use a light panel or light box at the doctor's office or at home.

• Psoralen plus ultraviolet A (PUVA) phototherapy. This treatment combines oral or topical use of a medicine called psoralen with exposure to ultraviolet A (UVA) light. Psoralen makes the body more sensitive to this light. PUVA is normally used when more than 10 percent of the skin is affected or when rapid clearing is needed. While more effective than UVB phototherapy, long-term treatment can increase the risk of skin cancers.

Light therapy is now being combined with other therapies, such as the retinoid-like acitretin. Other combinations use UVB plus coal tar and anthralin-salicylic acid paste or PUBA with oral retinoids and hydroxyurea.

Systemic treatment for psoriasis

Doctors sometimes prescribe medicines that are taken internally for more severe forms of psoriasis, particularly when more than 10 percent of the body is involved.

• Methotrexate slows cell production by suppressing the immune system. It can cause liver damage or other side effects. As a precaution, doctors do not prescribe it for people with long-term liver disease or anemia. Pregnant women and women who are planning to get pregnant should not use methotrexate.

• Cyclosporine also suppresses the immune system. It may provide quick relief of symptoms, but it usually works only while it's being taken. Cyclosporine has a number of side effects. Women who are pregnant or breast-feeding should not use it.

• Hydroxyurea is less toxic but also less effective than methotrexate or cyclosporine. It is sometimes combined with PUVA or UVB. It also has side effects and must be avoided by pregnant women or those who are planning to become pregnant.

• Retinoids have vitamin A-like properties. They may help severe cases of psoriasis that do not respond to other therapies. Because it can cause birth defects, women taking it must protect themselves from pregnancy beginning 1 month before through 3 years after treatment. Most people have a return of psoriasis after the treatment is stopped.

• Antibiotics are used when an infection triggers the outbreak of psoriasis.