Topical corticosteroids in plaque psoriasis: a systematic review of efficacy and treatment modalities.

International audienceINTRODUCTION: Topical steroids are used for more than 50 years to treat mild-to-moderate plaque psoriasis. The purpose of this systematic review was to evaluate the efficacy but also the optimal modalities of administration of topical corticosteroids in psoriasis i.e. influence of steroid potency on clinical response, putative impact of topical formulation, occlusion procedure, rate of application to control the initial response and the potential interest of a maintenance treatment to prolong psoriasis clearance. Material and METHODS: A systematic search was performed between 1980 and January 2011 in Medline, Embase and Cochrane databases (English and French language, adults), using the keywords 'psoriasis'/exp/mj AND 'corticosteroid'/exp/mj. To analyse response across studies, three levels of response were categorized depending on the data available in studies: percentage of patients who achieved more than 50%, 75% or 90% improvement of initial psoriasis severity. RESULTS: From an initial selection of 1269 references, 1166 references were excluded on reading the title or the abstract and 32 on reading the article and 71 were finally retained and analysed. Fifty randomized controlled trials (RCT) assessing topical steroids in the initial treatment of mild-to-severe psoriasis body plaque psoriasis were retained: 40 were parallel-group studies and 10 were within-patient studies. Treatment duration was mostly 4 weeks. Sample size varied from 30 to 1 603 patients. Outcome measures to assess efficacy were highly variable. A total of 30-90% patients across parallel group studies experienced more than 50% of initial mild-to-severe psoriasis improvement while from 7% to 85% experienced more than 75% improvement and from 5% to 85% experienced at least 90% of improvement. The success rate in the within-patient studies varied from 10% to 70%. Eighteen RCT were performed in scalp psoriasis: 16 were parallel-group and two were within-patient studies, with a treatment follow-up time from 2 weeks to 6 months, enrolling 42-1417 patients. A total from 40% to 75% patients across studies experienced more than 75% of initial scalp psoriasis improvement and from 43% to 90% experienced more than 90% initial psoriasis improvement. Only three RCT studies evaluated topical steroids as a maintenance treatment for body psoriasis and one for scalp lesions. Despite heterogeneity in treatment schedule, topical steroid intermittent maintenance treatment was shown to prolong remission. The literature analysis did not provide with high evidence-based quality data on the role of formulation, topical steroid potency, number of applications per day to obtain the highest rate of success excepting occlusion dressing which provided with additional benefit. CONCLUSION: The clinical development of topical steroids in psoriasis did not follow state of the art modern methodology. Treatment success appears to be highly variable across studies. Maintenance intermittent treatment appears to be useful to prolong remission. Recommendations concerning topical steroids treatment modalities in plaque psoriasis should be mostly based on expert opinion