Combinations of classical time-honoured topicals in plaque psoriasis: a systematic review

Despite the availability of newer topical treatments, classical topical treatments for chronic plaque psoriasis still have an important position for selected patient populations. The vast majority of patients are treated with a combination of topicals. The question arises: what is the evidence behind these approaches?

To systematically review all available literature on efficacy and safety of combinations of classical topical treatments in chronic plaque psoriasis, including all combinations with dithranol, coal tar and penetration enhancers, and ultimately, to propose recommendations for combination treatment.

Standardized literature searches in PubMed, EMBASE and the Cochrane Controlled Clinical Trial Register, and allocation of the degree of evidence was carried out.

In total 2918 publications on topical combination therapy were revealed, of which 48 articles on combinations of classical treatments. In this article, the results concerning the 19 included publications are stated. The majority of combination regimens is at least as effective as monotherapies, and is generally well tolerated.

Methods of classical treatments are not standardized and different protocols in different treatment settings are used. Therefore the interpretation of study results cannot be generalized. Most evidence was found to recommend the use of a combination regimen of topical corticosteroids and salicylic acid, above monotherapy with either component. Also, the combinations of dithranol with superpotent corticosteroids or with coal tar may be preferred above both monotherapies. In case first-line treatments and systemic therapies are not effective or contraindicated, combinations of classical topicals may provide an important opportunity.