Topical Treatments
Topical medications are applied directly to the affected skin. They can control many mild cases.
Corticosteroids (cortisone and many others) have long been used to treat psoriasis. They clear the skin for a limited time. Corticosteroids are available in creams, ointments, lotions, oils, shampoos, and foams, which are convenient for scalp treatments or other special applications. Potential side effects are mainly skin thinning and irritation.
NOTE: Physicians may also give corticosteroids in low-dose injections or pills. But long-term use of injected or oral corticosteroids (not external forms) can cause severe side effects, as can abruptly stopping their use. Both must be discontinued gradually.
Retinoids are prescription vitamin A-like gels and creams, such as tazarotene (Tazorac and Avage), that slow the rate of skin-cell growth. They have fewer side effects than corticosteroids but are slower acting. Improvement usually begins within 2 months. Women who may become pregnant or plan to become pregnant within 3 years should not use retinoids in any form.
Prescription forms of vitamin D3 can be used in small amounts when psoriasis affects less than 20% of the body's surface. These drugs, such as calcipotriene (Dovonex) and calcitriol (Vectical), slow the rate of skin-cell growth and are very different from the regular vitamin D supplements you can buy in any drugstore.
Today, combinations of vitamin D3 drugs and corticosteroids are widely considered the most effective treatments for mild to moderate psoriasis.
Anthralin is a cream that slows the production of skin cells (brand names include Psoriatec, Drithocreme, and Zithranol-RR). It tends to work when other treatments haven't, but it doesn't always remove skin lesions completely. Also, it needs to be handled carefully, as it can stain skin, hair, nails, bedding, sinks, and bathtubs (Dritho-Scalp is a shampoo form).
Coal tar treatments for psoriasis have been used for at least a century, and, yes, they're derived from coal. Available in creams, gels, soaps, shampoos, bath solutions, and more, coal tar's benefits are long lasting, and it has fewer side effects than corticosteroids. The drawbacks: It smells bad, stains the skin (light-colored hair, too), and makes skin sensitive to sunlight.
Although coal tar contains carcinogens, the FDA considers the level of exposure not significant enough to increase the risk of cancer over time.
Salicylic acid can be combined with other topical treatments (coal tar, cortisone, or anthralin) to help remove scales and dead skin.
Topical immunomodulators (TIMs), such as tacrolimus ointment (Protopic) and pimecrolimus cream (Elidel), are eczema drugs sometimes used for psoriasis and may be useful for sensitive, thin-skinned areas, such as the face, or in skin-fold areas (under the breasts, in the groin). But these drugs are still considered investigational for psoriasis, and they can interact with a long list of medications and vaccines, which limits their use.
