Topical Medications:

Topical medications are those applied only to the surface of the body. They come in the following forms:

• Creams
• Foams
• Gels
• Lotions
• Occlusive tapes
• Ointments
• Shampoos
• Solutions
• Sprays

In general, topical treatments are the first line for mild-to-moderate psoriasis, but they may also be used, alone or in combination, with more powerful treatments for moderate-to-severe cases. Topical medicines rarely clear up symptoms completely, however.

Topical Corticosteroids

Topical corticosteroids are the mainstay of psoriasis treatment in the United States. They work for most patients. Such treatments:

• Decrease inflammation
• Block cell production
• Relieve itching

Corticosteroids are available in a wide range of strengths, and are generally given as follows:

• Less potent drugs are used for mild-to-moderate psoriasis.
• Stronger drugs are reserved for more severe disease.

In the past, topical steroids have been used twice a day. Studies are reporting, however, that certain drugs may work just as well if taken once a day. Most studies have evaluated high-potency steroids, but one study suggested that those of medium strength, such as triamcinolone (Aureocort, Tri-Adcortyl), may be equally beneficial as a once-daily treatment. However, corticosteroids used alone clear psoriasis in only 4 - 36% of patients.

Combination therapy. Combinations with other drugs are often needed. For example, an effective topical regimen uses the following drug combination for maintenance therapy:

• A high-potency steroid (such as halobetasol) on the weekend
• A vitamin D3 topical medication called calcipotriene, twice daily on weekdays

Side Effects. The more powerful the corticosteroid, the more effective it is. But it also has a higher risk for severe side effects. Side effects may include:

• Acne
• Burning
• Dilated (widened) blood vessels
• Dryness
• Irritation
• Loss of skin color
• Thinning of the skin; skin may become shiny, fragile, and easily cut

Loss of Effectiveness. In most cases, patients become tolerant to the effects of the drugs, and the drugs no longer work as they should. Some experts recommend using intermittent therapy (also called weekend or pulse therapy). This type of treatment involves applying a high-potency topical medication for 3 full days each week.

Coal Tar

Coal tar preparations have been used to treat psoriasis for about 100 years, although their use has declined with the introduction of topical vitamin D3-related medicines. Crude coal tar stops the action of enzymes that contribute to psoriasis, and helps prevent new cell production. Tar is often used in combination with other drugs and with ultraviolet B (UVB) phototherapy.

Side Effects. Preparations have the following drawbacks:

• Stains on clothing
• Skin irritation
• Sun sensitivity and increased risk of sunburn for up to 24 hours after use

Anthralin

Anthralin (Dritho-Scalp, Drithocreme, Micanol) slows skin cell reproduction and can produce remissions that last for months. It is recommended only for chronic or inactive psoriasis, not for acute or inflamed eruptions. People with kidney problems should use anthralin with caution.

As with tar, anthralin's use has also declined since the introduction of the topical vitamin D-related medicines, but newer formulations, such as Micanol, have made its use more tolerable. Micanol (Psoriatec) is an anthralin formulated in microcapsules, which dissolve and allow the drug to be delivered directly to the target skin areas. It is particularly useful for scalp psoriasis, and it is less likely to stain.

Side Effects. Anthralin may cause the following side effects:

• Skin irritation and burning
• Staining of clothes, hair, fabrics, plastics, and other household products

Patients should not use anthralin on their faces. Fair-skinned people should generally avoid it. Triethanolamine (CuraStain) is a chemical that can neutralize anthralin and help reduce irritation from short-contact anthralin treatment. It should be applied 1 or 2 minutes before washing off the anthralin. It is then reapplied after drying the skin.

Washing stained items with hypochlorite (Clorox) detergents can help remove stains. Many people use disposable gloves while applying the treatment to avoid staining their hands.

Application. Apply anthralin only to the psoriasis plaques. Rub the cream in well, and wipe off any excess. Wash off only with lukewarm water, not soap. Using hot water will trigger the staining action. A technique called short-contact anthralin therapy (SCAT), also called minute therapy, is useful for local areas of psoriasis. In such cases, anthralin is applied for only 10 minutes to an hour.

Topical Vitamin D3-Related Treatments

A topical form of vitamin D3, calcipotriene (Dovonex) is proving to be both safe and effective. It is now available in a foam preparation, which makes using it even easier. Several other topical vitamin D3-related drugs showing promise include maxacalcitol (Oxarol), tacalcitol, and calcitriol (Silkis).

Calcipotriene appears to:

• Block skin cell reproduction
• Enhance the maturity of keratinocytes (the impaired skin cells in psoriasis)
• Act as an anti-inflammatory

It works just as well as moderate topical corticosteroids, short-term anthralin, and coal tar in improving mild-to-moderate plaque psoriasis. Unlike with steroids, patients do not develop thinning of the skin or tolerance to the drug.

Using the drug in combination with other topical and systemic treatments may improve its effectiveness. Calcipotriene doesn't work as well as the highest potency corticosteroids, but products or regimens that combine both medications are proving to be more effective than either one alone. Taclonex, an ointment containing both calcipotriol and betamethasone, was approved by the U.S. Food and Drug Administration (FDA) in January 2006 for the treatment of adults with psoriasis. Studies show the combination works better than either drug alone.

Combining vitamin D ointments with systemic medicines, notably methotrexate, acitretin, or cyclosporine, increases its effectiveness. Because combining medications allows patients to use lower doses of both medications, it reduces side effects.

Studies also report success in some patients who use vitamin D ointments in combination with phototherapy treatment.

Side Effects. Calcipotriene may cause the following side effects:

• A possible lowering of vitamin D levels, which may affect bone growth in some children
• A possible increase in blood calcium levels (seen in some people who apply calcipotriene to large areas)
• Skin irritation in about 20% of patients, particularly on the face and in skin folds

Calcipotriene appears to cause greater skin irritation than potent corticosteroids. Diluting the drug with petrolatum or applying topical corticosteroids to sensitive areas may prevent this problem.

Topical Retinoids

Retinoids are related to vitamin A. They are used for various skin disorders. Tazarotene (Tazorac) was the first topical retinoid found to be effective for mild-to-moderate psoriasis. It is available in cream or gel form.

Unlike with steroids, patients do not develop thinning of the skin or tolerance to the drug. Only a very small amount is needed on each lesion. It can be used on the scalp and nails, but it is not recommended for the genital areas or around the eyes. The gel should be used on only 20% of the body at any time; the cream on up to 35% of the body.

Combining topical retinoids with other psoriasis treatments, such as topical steroids, works better than using the drug by itself.

Side Effects. Tazarotene may cause dryness and irritation of healthy skin. Applying zinc oxide and moisturizer around the treated area can protect the healthy skin.

At levels high enough to be effective for psoriasis, tazarotene can cause severe skin irritation on treated areas. This medicine is usually used in combination with other treatments, allowing a lower dose. Mixing the drug in equal amounts with petroleum jelly (Vaseline) at first, and then gradually increasing the amount of tazarotene may help the skin areas become less sensitive. The skin can become very red while it is actually improving.

Vitamin A derivatives (drugs related to vitamin A) have been associated with birth defects and should not be used by women who are pregnant, who wish to conceive, or who are nursing.

Salicylic Acid

Salicylic acid applied to the skin helps remove scaly plaque and enhance the actions of other medications. It should not be used to cover wide areas of the body, because it can cause nausea and ringing in the ears. Combinations with high-potency steroids, such as mometasone furoate (Combisor), clobetasol propionate, and betamethasone, are proving to be very helpful. Only Combisor is available in the United States.

Occlusive Tapes

Watertight (occlusive) tapes or wrappings may help heal psoriasis. Occlusive tapes are particularly useful for psoriatic cuts on the palms and soles. In such cases, the tape should be applied across the cuts until they heal.

Occlusive tapes retain sweat, which helps restore moisture to the outer skin layer and prevent scaling. They also protect against abrasion and irritation.

High-Potency Corticosteroid Tapes. Applying a corticosteroid beneath an occlusive tape, or using a tape that already has a potent corticosteroid (Cordran Tape) such as flurandrenolide may be especially beneficial. Studies are showing that high-potency corticosteroid-containing tapes are more effective than high-potency corticosteroid ointments alone.

However, the tapes are expensive and are associated with a high rate of skin irritation, increased secondary infections, and a greater chance of symptoms returning after treatment is stopped. Infection risk may be reduced by changing tapes every 12 hours.

The use of corticosteroids under occlusive tapes on large areas of psoriasis also increases the risk for adrenal insufficiency, a sometimes dangerous condition that occurs because the body loses its ability to produce natural steroids. Children are especially vulnerable to this effect.

Other Medications with Occlusive Tapes or Wrappings. The tapes may be used in combination with other medications, such as fluorouracil. Occlusive wrappings are not usually used with tazarotene (Tazorac), and should never be used without a doctor's recommendation.

Investigational Medications

Numerous topical medications are under investigation. One such medication, tacrolimus (Protopic), is an immunosuppressant that is proving to be useful in allergic skin disorders and is being studied for psoriasis. Studies have been mixed on its benefits, although new delivery methods may make it more effective. It may prove to be safe for sensitive areas, such as the face. Pimecrolimus (Elidel), a similar medication, is also being studied. In patients with psoriasis of the face, a 1% pimecrolimus cream applied twice a day may significantly improve symptoms.