Psoriasis

Treatment of Severe Scalp Psoriasis: From the Medical Board of the National Psoriasis Foundation
Chan CS, Van Voorhees AS, Lebwohl MG, et al
J Am Acad Dermatol. 2009;60:962-971

A task force of the National Psoriasis Foundation Medical Board has written a consensus statement on therapy for scalp psoriasis. A MEDLINE search for "scalp psoriasis" was performed and the results were graded on the basis of levels of evidence developed by Shekelle and colleagues.[1] Treatment recommendations within the consensus statement are divided into first- and second-line options, and first-line treatment options are further divided into those that are appropriate for short-term vs long-term use.

The recommended first-line, short-term therapy for scalp psoriasis is topical corticosteroids, which have been the mainstay in the treatment of scalp psoriasis for years. The lowest-strength agent that is efficacious is preferred, although in general high-potency agents can be used safely. A limited number of head-to-head studies have demonstrated the superior efficacy of topical corticosteroids in scalp psoriasis compared with other topical agents. However, the major limitation of these agents is that superpotent topical corticosteroids are approved by the US Food and Drug Administration (FDA) for a maximum of 4 weeks of consecutive use due to the risk for skin atrophy, striae, and telangiectasias. No studies exist supporting the safety of these agents for use on the scalp beyond this time period. Because steroid-sparing medications are associated with fewer long-term risks, agents such as calcipotriene/calcipotriol, salicylic acid, dithranol/anthralin, coal tar, and topical retinoids (ie, tazarotene) are recommended as first-line, long-term therapy for scalp psoriasis. Combination therapy with the aforementioned topical agents has advantages over monotherapy because of enhanced efficacy with minimized toxicity and side effects.

All other treatment options for scalp psoriasis were based on anecdotal evidence. Alternative first-line treatment options include intralesional corticosteroids, which should be used only for localized scalp disease due to the increased risk for side effects associated with this method of administration. Alternative second-line treatment options include phototherapy and systemic medications. Although phototherapy is an effective treatment for nonscalp psoriasis, this modality is difficult to use on the scalp due to the presence of hair, which blocks the adequate penetration of ultraviolet light. To date, no studies exist that have specifically evaluated systemic treatments for scalp psoriasis. However, on the basis of the known efficacy of systemic agents in plaque psoriasis, a therapeutic trial of these agents can be considered when scalp psoriasis has not responded adequately to the aforementioned topical therapies.

Viewpoint
The scalp is the most common area of psoriasis involvement and one of the most difficult to treat. Scalp involvement occurs in approximately 79% of psoriasis patients[2] and historically has been treated with low-potency topical steroids. FDA safety labeling limits the consecutive use of superpotent topical corticosteroids to 4 weeks. However, despite the lack of clinical trial data supporting the use of these agents for more than 4weeks, most -- if not all -- clinicians use long-term dosing of topical corticosteroids in the treatment of scalp psoriasis, especially corticosteroids of less than super potency. Underused options are coal tar, anthralin, and salicylic acid. Coal tar and anthralin are safe and effective for long-term use but often stain hair and may have a distinct, pungent smell. Salicylic acid is effective for the removal of thick scale, which allows for better penetration of other topical agents, rendering them more efficacious. Combination treatment regimens using topical steroids and topical nonsteroidal treatments can minimize or avoid the risk for steroid side effects. Because scalp skin is quite thick, some of the common side effects of topical steroids, such as atrophy, striae, and telangiectasias, are virtually never seen on the scalp. Consequently, the main safety concern with the use of topical steroids on the scalp is adrenal suppression, especially during long-term use of superpotent topical steroids. To minimize such risk, we recommend intermittent use of regimens with potent agents, such as the one we use with clobetasol propionate spray: 2-4 weeks on, followed by 2-4 weeks off, then back to 2-4 weeks on, if necessary, and so on. Used in this way, it is unlikely that the adrenal suppression encountered will be anything more than transient physiologic adrenal suppression rather than pathologic adrenal suppression leading to clinically relevant adrenal insufficiency.

References
Shekelle PG, Woolf SH, Eccles M, Grimshaw J. Clinical guidelines: developing guidelines. BMJ. 1999;318:593-596.
Van de Kerkhof PC, Steegers-Theunissen RP, Kuipers MV. Evaluation of topical drug treatment in psoriasis. Dermatology. 1998;197:31-36. Abstract

Guidelines of Care for the Management of Psoriasis and Psoriatic Arthritis. Section 3. Guidelines of Care for the Management and Treatment of Psoriasis With Topical Therapies
Menter A, Korman NJ, Elmets CA, et al
J Am Acad Dermatol. 2009;60:643-659

A work group of experts in psoriasis is formulating consensus guidelines for the management of psoriasis and psoriatic arthritis. The individual sections of these guidelines focus on different aspects of psoriasis management. Section 3 pertains to the management of psoriasis with topical therapies. It discusses the efficacy and safety of corticosteroids, vitamin D analogs, tazarotene, tacrolimus, pimecrolimus, emollients, salicylic acid, anthralin, and coal tar. Combination therapies are also evaluated.

Data were obtained using an evidence-based model via search of the MEDLINE database from 1960 to 2008. The evaluation of evidence was based on the 3-point numeric grading scale of the Strength of Recommendation Taxonomy used in primary care journals: I = good-quality patient-oriented evidence; II = limited-quality patient-oriented evidence; and III = other evidence, including consensus guidelines, opinion, or case studies.[1] Clinical recommendations were then formulated using the following scale: A = recommendation based on consistent and good-quality evidence; B = recommendation based on inconsistent or limited-quality patient-oriented evidence; C = recommendation based on consensus, opinion, or case studies.

Ultimately, the work group formulated recommendations for the practical clinical use of each of the topical agents and commented on the following aspects: indications, dosing, efficacy, contraindications/adverse reactions, pregnancy/nursing use, and pediatric use. The document is too complex to summarize in this review, but the reader is referred to the especially helpful tables in the article that summarize treatments, strength of recommendation, level of evidence, and supporting references.

Viewpoint
Psoriasis affects approximately 2% of the population, and clinicians need to become familiar with the treatment of this cutaneous disease. The expanding arsenal of agents used to treat this often complex condition is growing constantly. This set of guidelines, presented in an evidence-based approach by top psoriasis experts, is crucial to the care of people with psoriasis. In our opinion, every clinician who treats psoriasis should use this document. Although not every patient presents a straightforward case, these guidelines should be used as a starting point for the creation of treatment regimens based on each patient's unique disease parameters. In our clinical practice, these guidelines are not only an extremely useful reference for patient care but also an essential "textbook" for the education of medical students, residents, and fellows who are attempting to become familiar with the management of psoriasis patients.

Reference
Ebell MH, Siwek J, Weiss BD, et al. Simplifying the language of evidence to improve patient care: strength of recommendation taxonomy (SORT): a patient-centered approach to grading evidence in medical literature. J Fam Pract. 2004;53:111-120. Abstract

Cochrane Review: Topical Treatments for Chronic Plaque Psoriasis
Mason AR, Mason J, Cork M, Dooley G, Edwards G
Cochrane Database Syst Rev. 2009;(2):CD005028. DOI: 10.1002/14651858.CD005028.pub2.

The Cochrane Collaboration is an independent organization that produces quarterly systematic reviews of healthcare interventions called Cochrane Reviews. These reviews seek to address the effectiveness and appropriateness of disease-related treatment regimens in a comprehensive, unbiased, and scientifically validated manner. The purpose is to facilitate the choices made by healthcare providers and policy makers regarding the care of patients. This recent Cochrane Review focuses on topical treatments for plaque psoriasis with 2 goals in mind: (1) to compare the effectiveness, tolerability, and safety of topical treatments for chronic plaque psoriasis with placebo; and (2) to compare vitamin D analogs with other topical treatments.

Results of 13 randomized controlled trials with a total of 21,448 study participants revealed the following regarding the topical treatments for plaque psoriasis:

Vitamin D agents, corticosteroids, anthralin, and tazarotene were each more effective than placebo;
Head-to-head comparisons of vitamin D agents vs potent/very potent corticosteroids showed no statistically significant efficacy differences;
The combination of a vitamin D agent and a steroid was more efficacious than either agent alone;
Vitamin D agents were superior to coal tar;
Vitamin D agents were more effective with occlusion and/or twice-daily application;
Potent corticosteroids were less likely than vitamin D agents to cause local adverse events such as skin irritation; and
There was no difference in frequency of systemic adverse events between placebo and all other topical agents (although the Cochrane authors pointed out that this may be due to absence of evidence rather than evidence of absence).
Viewpoint
The authors recommend that practicing dermatologists become acquainted with the Cochrane Library as a source of sound scientific information for treatment decisions. The discerning reader has the opportunity to appraise the actual data used by the authors to draw conclusions on treatment regimens by reviewing the full document version, while the more time-constrained reader can quickly peruse the summary section for a brief overview.

A quick search for Cochrane Reviews on psoriasis revealed 6 related articles. With the advent of biologic agents, it is impressive that the Cochrane reviewers chose to focus on the use of topical agents in the treatment of psoriasis. Because the majority of psoriasis patients have localized involvement, topical agents are and should remain the first-line agents of choice in most psoriasis cases and will continue to be a mainstay of treatment, except for those with generalized disease.

The obvious limitation of this document is that the information cannot be generalized to long-term maintenance therapy because the studies of these topical agents were, on average, only 6 weeks in duration. One-year safety and efficacy data are available only for vitamin D analogs (calcipotriene cream, calcipotriene plus betamethasone dipropionate ointment, and calcitriol ointment). The results showed that these agents are safe and effective for up to 1 year, and clinical practice suggests that they are safe and effective for even longer use. More long-term studies are needed, especially for agents that are not vitamin D analogs.

Abstract

This activity is supported by an independent educational grant from Galderma.