Am Fam Physician. 2010;81(5):596-598
Author disclosure: Nothing to disclose.
Clinical Scenario
A 45-year-old woman with a 20-year history of psoriasis presents with worsening symptoms. She has been using topical corticosteroids for two weeks after a flare-up and would like to know if there are other treatments available.
Clinical Question
What are effective topical treatments for chronic plaque psoriasis?
Evidence-Based Answer
Topical vitamin D analogues, corticosteroids, anthralin, and tazarotene (Tazorac) are all more effective than placebo (Strength of Recommendation [SOR] = A, based on consistent and good quality patient-oriented evidence). Vitamin D and high-potency corticosteroids were equally effective when compared head to head, but were more effective in combination than either product alone (SOR = A). Vitamin D was more effective than coal tar polytherapy (SOR = A). Corticosteroids had fewer local reactions compared with vitamin D (SOR = A).
Practice Pointers
In this Cochrane review, treatment duration of the trials ranged from one to 24 weeks, with a mean treatment duration of six weeks.1 A variety of treatments were found to be more effective than placebo in single studies, but the most robust findings were for topical vitamin D analogues and topical corticosteroids. Vitamin D was reviewed in 15 trials (n = 2,556) and was found to be more effective than placebo for all outcomes (standard mean difference [SMD] = −1.30 [SMD of −1 to −2 indicates moderate effectiveness]; 95% confidence interval [CI], −1.57 to −1.03). This overall effect varied greatly among the different studies, although twice daily dosing of calcipotriol (calcipotriene [Dovonex] in the United States) was more effective than once daily dosing, and occlusion of topical vitamin D can also enhance its effectiveness.
Potent (group II) and very potent (group I) topical corticosteroids were examined in 11 (n = 1,232) and five (n = 684) studies, respectively. They were superior to placebo on all outcome measures, with an SMD for the potent group of −1.09 (95% CI, −1.26 to −0.92) and an SMD for the very potent group of −1.42 (95% CI, −1.72 to −1.11). No statistically significant difference was noted between corticosteroids and vitamin D, but combined products performed better than either alone (SMD = −0.46; 95% CI, −0.60 to −0.3).
Another effective option was dithranol (anthralin in the United States), which inhibits energy production at the mitochondria, resulting in decreased DNA production in rapidly dividing psoriatic cells. It was more effective than placebo, with an SMD of −1.14 (95% CI, −2.22 to −0.06). Comparisons with vitamin D showed mixed results.
The topical retinoid tazarotene was more effective than placebo (SMD = −0.91; 95% CI, −1.16 to −0.67). No statistically significant difference was noted when tazarotene was compared with vitamin D. Coal tar polytherapy (combined with coconut oil and salicylic acid, or allantoin and hydrocortisone cream, or dithranol) was not as effective as vitamin D in head-to-head comparisons (SMD = −0.64; 95% CI, −1.07 to −0.21).
Factors affecting withdrawal from treatment included local and systemic adverse effects. However, vitamin D and potent corticosteroids had fewer withdrawals from treatment for any reason than placebo. Topical corticosteroids were slightly better tolerated than vitamin D, whereas dithranol was not as well tolerated.
Cochrane Abstract
Background: Chronic plaque psoriasis is the most common type of psoriasis and is characterized by redness, thickness, and scaling. First-line management of chronic plaque psoriasis is with topical treatments, including vitamin D analogues, topical corticosteroids, tar-based preparations, dithranol, salicylic acid, and topical retinoids.
Objectives: To compare the effectiveness, tolerability, and safety of topical treatments for chronic plaque psoriasis with placebo; to compare vitamin D analogues with other topical treatments.
Search Strategy: The Cochrane Skin Group's Trials Register was searched (December 2004). To update an unpublished 2002 review, the researchers also searched CENTRAL in the Cochrane Library (2005; Issue 1); Medline (to February 2005); EMBASE (to August 2005); Science Citation Index (to 2005); Biosis (to 2005); Dissertation Abstracts (all publication years); Inside Conferences (all publication years); SIGLE (to 2005); National Research Register (all projects with a start date of 2001 to 2005); and metaRegister of Current Controlled Trials.
Selection Criteria: Randomized trials comparing treatments with placebo or with vitamin D analogues in persons with chronic plaque psoriasis.
Data Collection and Analysis: One author extracted study data and assessed study quality. A second author checked these data. Researchers routinely contacted trial lists and companies for missing data. They extracted data on withdrawals and adverse effects.
Main Results: The review included 131 randomized controlled trials with 21,448 participants. Vitamin D was significantly more effective than placebo, although there was a wide variation in effect size, with the standardized mean difference (SMD) ranging from −0.82 (95% confidence interval [CI], −1.34 to −0.29) to −1.90 (95% CI, −2.09 to −1.71). With one exception, all corticosteroids performed better than placebo, with potent corticosteroids (SMD = −0.95; 95% CI, −1.11 to −0.80; I2 [heterogeneity statistic] = 61.1 percent; 17 studies; 2,386 participants) having smaller benefits than very potent corticosteroids (SMD = −1.29; 95% CI, −1.45 to −1.13; I2 = 53.2 percent; 11 studies; 1,571 participants). Dithranol and tazarotene performed better than placebo. Head-to-head comparisons of vitamin D against potent or very potent corticosteroids found no significant differences. However, combined treatment with vitamin D/corticosteroid performed significantly better than either vitamin D or corticosteroid alone. Vitamin D performed better than coal tar, but findings relative to dithranol were mixed. Potent corticosteroids were less likely than vitamin D to cause local adverse effects. No comparison of topical agents found a significant difference in systemic adverse effects.
Authors' Conclusions: Corticosteroids perform as well as vitamin D analogues and are associated with a lower incidence of local adverse effects. Further research is required to inform long-term maintenance treatment.
These summaries have been derived from Cochrane reviews published in the Cochrane Database of Systematic Reviews in the Cochrane Library. Their content has, as far as possible, been checked with the authors of the original reviews, but the summaries should not be regarded as an official product of the Cochrane Collaboration; minor editing changes have been made to the text (http://www.cochrane.org).
Although this review focuses on topical treatments for psoriasis, many patients who do not have localized disease will require systemic treatments, such as methotrexate, cyclosporine (Sandimmune), narrowband and broadband ultraviolet B, psoralen plus ultraviolet A, oral retinoids, and newer biologic agents.2 Because of its association with an increased risk of progressive multifocal leukoencephalopathy, efalizumab (formerly Raptiva) is no longer available in the United States, and it has a boxed warning on tumor necrosis factor due to increased risk of lymphoma and other cancers.3
