Abstract and Introduction
Background Chronic plaque psoriasis is the most common type of psoriasis and is characterized by redness, thickness and scaling. First-line management is with topical treatments.
Objectives Our objective was to establish the effectiveness, tolerability and safety of topical treatments for people with chronic plaque psoriasis of the scalp, assessing placebo-controlled trials of all treatments and head-to-head trials that assessed vitamin D analogues.
Methods As part of a Cochrane review of topical treatments for psoriasis, we systematically searched electronic databases for randomized controlled trials. The review included 26 randomized controlled trials of treatments for psoriasis of the scalp with 8020 participants. Trials used several measures to assess changes in psoriasis severity: these were combined using the standardized mean difference metric and interpreted by reporting as a six-point global improvement score.
Results On effectiveness grounds, very potent or potent steroid treatments should be preferred to vitamin D3 analogue with approximately an average 10% additional improvement on a six-point scale. Vitamin D3 analogue combined with potent steroid appears slightly more effective than potent steroid monotherapy (3% additional improvement on a six-point scale). Rates of withdrawal from treatment and adverse events in trials were generally low and similar to those for placebo. There remains uncertainty about the atrophic potential of corticosteroid treatments for scalp psoriasis.
Conclusions Corticosteroids are more effective than vitamin D analogues and similarly tolerated. However, further research is needed to inform long-term maintenance treatment and provide appropriate safety data.
Psoriasis is a chronic inflammatory skin disease with a prevalence ranging from 1–2% in the U.K. and northern European populations[1,2] down to 0·1–0·3% in the Far East and China. Chronic plaque psoriasis may be localized or widespread and accounts for 90% of psoriasis cases; it is characterized by red patches of thickened skin (plaques) covered in silver scales. Any area of the body may be affected, but the main areas are the knees, elbows, lower back and scalp. There is a wide spectrum of disease severity from a single plaque to involvement of more than 90% of the skin surface. Psoriasis can lead to social isolation, stigmatization and can adversely affect quality of daily life.[8–15] Psoriasis of the scalp affects up to 79% of people with chronic plaque psoriasis; the scalp is typically the first area of the body to be affected, and the frequency of involvement increases with the duration of the disease.
Disease progression is complex and appears to be influenced by many factors including local trauma, infections, certain drugs (such as beta-blockers, lithium, chloroquine and nonsteroidal anti-inflammatory drugs), the duration of antipsoriatic treatments, endocrine factors, sunlight, alcohol, smoking and stress. The skin lesions of psoriasis are characterized by cells multiplying too quickly (epidermal hyperproliferation), cells not maturing normally (abnormal keratinocyte differentiation) and the presence of cells which cause inflammation (a lymphocyte inflammatory infiltrate).[18–20] Psoriasis is now recognized as an immune-mediated disorder, with tumour necrosis factor-α, dendritic cells and T cells all contributing to its pathogenesis. A meta-analysis of three genome-wide association studies identified 15 new chromosomal susceptibility loci for psoriasis, bringing the total number of loci known to be associated with psoriasis to 36. Several of these loci are involved in the regulation of the skin's innate immune response. They provide confirmation of the role of several existing biologic therapies and provide new targets for drug development.
Topical treatments are the main therapy for psoriasis of the scalp, whatever the level of disease severity. They include vitamin D analogues, used alone or in combination with potent corticosteroids; potent and very potent corticosteroids; coal tar; and other treatments.[23,24] Scalp psoriasis is one of the most challenging forms of the disease to manage, because the presence of hair makes the use of ointments and cream-based products 'difficult and messy'. Lotions, shampoos, gels and sprays are all used as vehicles for active treatment.
This paper is based on a Cochrane review[26,27] most recently substantially amended in the Cochrane Library 2013, issue (3) (see https://www.thecochranelibrary.com). Cochrane reviews are regularly updated as new evidence emerges and in response to feedback; the Cochrane Library should be consulted for the full and most recent version of the review.
The objective was to compare the effectiveness, tolerability and safety of topical treatments for people with chronic plaque psoriasis of the scalp relative to placebo, and to compare vitamin D analogues head-to-head with other topical treatments.
The British Journal of Dermatology. 2013;169(3):519-527. © 2013 Blackwell Publishing