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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.
Topical steroids applied to the scalp were more effective and safer for treating psoriasis than topical vitamin D alone.
Using steroids in combination with vitamin D was statistically better than using a steroid alone, but the difference was not considered clinically important. The combination ointment costs almost £20 for 30g compared to a 30g tube of typical steroid ointment which costs about £4.
Scalp psoriasis is a common condition that can be itchy and embarrassing for many. A variety of topical lotions, solutions or gels are available to treat the condition, so this review of published research aimed to help doctors and patients find out which was the most effective and safest option.
This systematic review found 59 trials mainly of steroids or vitamin D, alone or in combination, lasting less than six months. Just over half were known to be sponsored by the manufacturers of the products. This could mean that the results may be biased towards the publication of positive results. Another limitation is that the results are relevant to short term, less than 6 month use only.
The results are in line with current NICE guidelines, which recommend topical steroids alone first-line in different formulations and, if that doesn’t work, a combination of steroid and vitamin D.
Why was this study needed?
Psoriasis is a common condition affecting around two in every 100 people in Western Europe and the US. The vast majority of people with psoriasis have it affect their scalp causing red patches of skin covered in thick silvery-white scales.
These scaly lesions are visible and can cause embarrassment. Scalp psoriasis can also be extremely itchy, although some people have no discomfort. In extreme cases it can cause hair loss, although this is usually only temporary.
Topical treatments (creams and ointments for the skin) such as corticosteroids (steroids) and vitamin D are usually the first treatments tried, but applying them to the scalp is difficult because of hair on the head. It is also not clear which works best.
This study aimed to help doctors and patients decide which of the wide variety of topical treatments available work best, and the type and frequency of any side effects.
What did this study do?
This Cochrane systematic review included 59 randomised controlled trials of 11,561 participants up to August 2015. All ages were included.
The main outcomes of interest were ‘clearance’ or ‘response’ of psoriasis as assessed by a doctor or the patient themselves using ratings of whether scalp lesions had improved or cleared up completely. Adverse events requiring stopping of treatment, such as allergic reactions, were also recorded.
Three main comparisons of topical treatments were made: topical steroid alone versus vitamin D alone; combination therapy (corticosteroid and vitamin D therapy) versus steroid alone; combination therapy versus vitamin D alone.
Trials concerning these three outcomes were rated as moderate or high quality, most lasted less than six months, and around half were carried out or sponsored by the manufacturer of the study medication. Sponsor involvement can bias results – in this case they can be more likely to find differences where there are none, or discover differences that are artificially large.
What did it find?
- Patient-rated treatment response using steroids alone was 48% better than those on vitamin D only (Relative Risk [RR], 1.48% 95%CI 1.28 to 1.72). This meant around five patients would need to be treated with steroids to achieve one extra patient who rates themselves as having “responded” to treatment. Steroids in combination with vitamin D were 13% better than vitamin D alone meaning around 13 people would need to be treated for one extra person to benefit in the same way – a difference not considered to be clinically important.
- Patients and doctors gave similar ratings of improvements.
- Participants who applied vitamin D alone stopped treatment more often because of adverse effects than those who applied a topical steroid alone or in combination with vitamin D. (RR 0.70, 95% CI 0.58 to 0.85).
What does current guidance say on this issue?
For initial treatment of scalp psoriasis, 2012 NICE psoriasis guidance recommends a potent corticosteroid applied as a lotion, solution or gel once daily for four weeks.
If the lesions don’t clear up or improve satisfactorily it recommends trying a different formulation for a further four weeks (e.g. switching from gel to a shampoo or mousse) with or without topical agents to rid difficult to remove scale. If response to treatment is still unsatisfactory, a combined product containing calcipotriol monohydrate (vitamin D) and betamethasone dipropionate (a steroid) can be used once daily for four weeks or vitamin D alone once daily up to eight weeks.
What are the implications?
The review suggests topical steroids alone or in combination with vitamin D are more effective and safer at treating scalp psoriasis than vitamin D alone.
We should be cautious of taking these findings at face value as some trials were industry sponsored. An additional 14 trials were identified but unavailable for inclusion in the analysis. There is the potential that industry sponsorship favours publishing of positive results rather than negative findings. For this review most comparisons contained fewer than ten studies and the authors say they were not able to statistically test for this bias.
Other types of topical treatments, such as coal tar, were included in the scope of the review but there was insufficient evidence found to draw any conclusions.
Citation and Funding
Schlager JG, Rosumeck S, Werner R. et al. Topical treatments for scalp psoriasis. Cochrane Database Syst Rev. 2016;(2):CD009687.
No funding information was provided for this study.
Bibliography
NICE. Psoriasis: assessment and management. CG153. London: National Institute of Health and Care Excellence; 2012.
PAPAA. Scalp psoriasis. St Albans: The Psoriasis and Psoriatic Arthritis Alliance; 2015.
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