Topical therapies show promise for Psoriasis

Mar 6 2006

Psoriasis, a chronic skin condition characterized by thick, red, scaly patches that itch and bleed, not only makes the activities of daily life difficult, but also can affect a person's emotional well being.

Psoriasis affects more than 4.5 million adults in the United States with a large percentage of those patients living with mild or localized psoriasis, which in no way lessens the burden of this challenging skin condition. While new biologic treatments are available for patients with severe psoriasis, those with less severe psoriasis rely on topical therapies to manage their disease. In addition, some topical therapies that are approved for treating other skin conditions may be effective for the treatment of less severe psoriasis.

Speaking at the 64th Annual Meeting of the American Academy of Dermatology, dermatologist Linda Stein Gold, M.D., director of dermatology clinical research at the Henry Ford Health System in West Bloomfield, Mich., spoke about myths and misconceptions about the use of topical corticosteroids and some new topical treatment options for psoriasis.

"Topical treatments, such as corticosteroids, are considered the first line of treatment," said Dr. Stein Gold. "With the emergence of several new therapies, more people with psoriasis are experiencing substantial improvements and reporting a greatly enhanced quality of life."

Recent research has shown that calcineurin inhibitors (TCIs), such as tacrolimus ointment and pimecrolimus cream, may be effective in treating psoriasis, although they are currently only approved by the U.S. Food and Drug Administration (FDA) for the treatment of atopic dermatitis, another chronic skin condition in which the skin becomes itchy, dry and inflamed. TCIs interfere with the activation of T-cells, a type of white blood cell responsible for triggering immune responses that contribute to the development of skin conditions such as atopic dermatitis and psoriasis.

"In clinical trials, pimecrolimus and tacrolimus showed promise in treating facial psoriasis and inverse psoriasis, which is characterized by smooth, red lesions in the skin folds," stated Dr. Stein Gold. "Tacrolimus in the gel form is currently in clinical trials for the treatment of body psoriasis. Side effects tend to be mild and include minor itching and a sensation of warmth after application."

Another new topical medication that has been approved by the FDA to treat moderate to severe plaque psoriasis is clobetasol propionate spray. In spray form, clobetasol propionate penetrates the skin easily to diminish the psoriasis plaques and minimize inflammation. In a recent study, patients using the clobetasol propionate spray over a four-week period saw a marked decrease in their disease severity, with most patients considering their psoriasis clear or almost clear by week four. In follow-up interviews after the completion of the study, the greatest proportion of patients still considered their psoriasis to be clear or almost clear.

"Patients like the spray because it is easy to use and not as messy as other topical medications," explained Dr. Stein Gold. "That is important because patients who like using a product will be more inclined to consistently use the treatment as directed, which will lead to more rapid results."

Combinations with topical corticosteroids also are effective for the treatment of psoriasis. A combination of calcipotriene and betamethasone dipropionate, a vitamin D analogue and a potent corticosteroid, was recently approved by the FDA in an ointment form for the treatment of psoriasis.

In a recent study of patients using the combination once daily, more than 80 percent of patients with mild to localized psoriasis reported reaching a Psoriasis Activity and Severity Index (PASI) score of 50 or better after four weeks, which means that this measure of psoriasis severity improved by 50 percent from the start of the study. The PASI is the standard measurement tool to determine what percentage of the body is affected by psoriasis and how severe a patient's psoriasis is at any given time. In addition, many patients with severe psoriasis who participated in the study reported a reduction in PASI score of more than 70 percent.

Corticosteroids are the most frequently prescribed treatment for mild to moderate psoriasis because they decrease the rate at which skin cells grow and reduce inflammation, thereby also relieving the itch that often accompanies psoriasis. Topical corticosteroids vary in potency -- from extremely mild to very strong -- and come in several forms, including lotions and ointments. Topical corticosteroids are usually prescribed for a select purpose for a limited period of time due to potential side effects.

Two of the more serious side effects regarding the use of corticosteroids are adrenal suppression, where the adrenal glands would become unable to regulate hormones being released in the body; and tachyphylaxis, where the body develops immunity to a certain treatment regimen. Whether or not tachyphylaxis really occurs is controversial in many medical circles. "The most important ways to allay patients' concerns about using corticosteroids and to prevent conditions like these from arising, are to educate patients about the importance of using these medications as prescribed and to encourage them to talk with their dermatologist if they have any questions," said Dr. Stein Gold.

"The latest developments in psoriasis therapies are really a positive step forward in finding innovative ways to treat this chronic skin condition," said Dr. Stein Gold. "As more and more research is being conducted in this area, I'm confident that dermatologists can help more psoriasis patients than ever before find the best therapy available for their condition."