Psoriasis - Topical Medications

Side Effects. Tazarotene can cause dryness and irritation, including on normal skin. Applying zinc oxide around the treated area can protect the healthy skin. Using a moisturizer can help reduce dryness. At levels high enough to be effective for psoriasis, tazarotene can cause severe skin irritation. This agent, then, is usually used in combination with other treatments, therefore allowing a lower dose. Mixing the drug in equal amounts with petroleum jelly (Vaseline) initially and then gradually increasing the amount of tazarotene may help the skin areas become less sensitive. It should be noted that the skin can become very red while it is actually improving.

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Vitamin A derivatives have been associated with birth defects, and the drug should not be used by women who are pregnant, who wish to conceive, or who are nursing.

Combinations. Combinations, such as with topical steroids or phototherapy, are more effective than the use of the agent alone. Unlike vitamin D3, phototherapy with either UVA or UVB inactivates this agent, although there is a higher risk for sunburn.

Salicylic Acid

Topical salicylic acid (the active ingredient in aspirin) is useful for removing scaly plaque and enhancing other agents. It should not be used to cover wide areas of the body, since 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 US.

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 one already impregnated with a potent corticosteroid (Cordran Tape), such as flurandrenolide, may be especially beneficial. Studies are showing that high-potency corticosteroid-impregnated tapes are more effective than using high-potency corticosteroid ointments alone. The downsides are the following:

The corticosteroid-impregnated tape is expensive.
It produces a higher incidence of skin irritation than the ointment alone.
It produces more pronounced rebound effects than the ointment (a relapse of symptoms after stopping treatment).
Steroid-impregnated tapes increase the risk for secondary infections, which may be prevented by changing the tapes every 12 hours.

The use of corticosteroids under occlusive materials on large areas of psoriasis 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 susceptible.

Other Medicationswith Occlusive Tapes or Wrappings. One study applied a cream containing fluorouracil underneath an occlusive tape. The dressing was applied two or three times a week for an average of about 16 weeks and resulted in 90% clearing in 11 out of 15 patients. Improvement persisted beyond three months in five patients.

Dovonex is also sometimes used with an occlusive wrapping. Occlusive wrappings are not usually used with Tazarotene (Tazorac) and should never be used without adoctor's recommendation.

Investigative Topical Agents

A number of topical agents are under investigation. One such agent, 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 agent, is also being studied.