Topical Treatments for Psoriasis

For most people with mild psoriasis, therapy begins with topical treatments. These are medicines in creams or ointments that are applied to the skin and scalp. There are a number of different approaches possible. It may take some time to find the one that works best for you.

Here are some of the most common topical treatments.

Corticosteroids, or steroids, are the most commonly prescribed medicine for psoriasis. They are often used to treat mild to moderate cases. They mimic some of the properties of naturally occurring hormones. They work by reducing inflammation and slowing the growth and build-up of skin cells. They come in all sorts of forms: creams, ointments, lotions, and foam, among others.

Topical corticosteroids come in different strengths designed for use on different parts of the body. Stronger potency steroids might be necessary for tough to treat patches of psoriasis on the elbows or knees. Weaker formulas are good for more sensitive skin on the face or groin. Directions for use vary depending on the particular medication. You will probably have to apply it once or twice a day. Your doctor may recommend that you try occlusion, which means applying the steroid cream and then wrapping the area with tape or plastic to increase the effect.

Steroids can cause side effects, such as thinning of the skin, changes in the skin color, bruising, and dilated blood vessels. Occlusion may increase these side effects. If you stop using steroids suddenly -- without gradually reducing the dose -- you may have a flare-up of psoriasis. If steroids are used on too much of the body, it's possible to develop more serious health problems.

Although steroids may work very well at first, your psoriasis may become resistant to them over time. Your doctor will probably only recommend them for short-term use. Topical corticosteroids are now often used in combination with Dovonex or Tazorac. In some cases, steroids may be injected instead of applied to the surface of the skin.

Vitamin D analogues. Dovonex (calcipotriene) is a form of Vitamin D that is sold as a cream, ointment or solution. It treats psoriasis by slowing down the growth of your skin, and it's safer than steroids for long-term use. Because Dovonex can irritate the skin, it should only be used in small amounts. Be careful not to get it on the healthy skin surrounding the psoriatic plaques. Your doctor will probably tell you to apply it twice a day. Dovonex is toxic if ingested, so keep it away from pets and children. You may use Dovonex together with a corticosteroid. Be careful with any medications that you use along with Dovonex. Some topical medicines, like salicylic acid, can stop it from working.

Other new vitamin D analogues are being studied for people with psoriasis. Several have been approved in other counties. They may become available in the U.S. in the future.

• Tazorac (tazarotene) and other retinoids are gels or creams derived from vitamin A. Retinoids come in different strengths to treat different types of psoriasis in different locations, including the scalp and nails. Usually, you would apply a small dab to each lesion once a day, before bed. Tazorac is often combined with steroid treatment. Women who are pregnant or who might become pregnant should probably not use topical retinoids.
• Anthralin (Drithocreme, Micanol, and others) is an effective medication for psoriasis that has been used for almost a century. It was originally derived from the bark of the araroba tree. Anthralin works by affecting the growth of skin cells in patches of psoriasis. It also reduces inflammation. The advantages of anthralin are that it works well, especially on hard to treat plaques, and causes no serious side effects. The disadvantages are that it can irritate the skin and stains everything, including clothing, sheets, and even skin. Because of its drawbacks, it's often reserved for cases where other treatments haven't worked.
• Coal tar has been a topical treatment for psoriasis since the nineteenth century. It's sold in many different forms, both with and without prescription, with strengths ranging from 0.5% to 5%. Tar shampoos are often helpful in treating psoriasis of the scalp. Other forms of coal tar can be applied to the skin. Coal tar has a reputation for being messy and smelly, which is unfortunately deserved. It can also stain clothing and irritate the skin. However, coal tar products that are on the market now are much easier to use than they once were. Follow the directions carefully. Some studies have shown that the chemicals in coal tar are cancerous, but this is only true at very high doses. It's safe to use coal tar if you follow your doctor's instructions.
• Salicylic acid is used to remove the scales that appear on patches of psoriasis. It's sold in lotions, gels, soaps and shampoos. Salicylic acid is especially useful in combination with other topical treatments. By removing the flakes of dead skin, salicylic acid allows these other medications to better penetrate the lesions. However, use salicylic acid sparingly. Putting too much on your body at once can be toxic.
• Moisturizers and lotions sold over the counter can keep your skin moist and help control flare-ups in mild cases of psoriasis. In general, the greasier lotions that trap moisture in your skin work better.

Calcineurin inhibitors. Tacrolimus and pimecrolimus can also be used to treat psoriasis. They are generally well tolerated. However, in 2006 a black box warning was placed on the prescribing information for these drugs because of a possible link between these medications and cases of lymphoma and skin cancer.