Background  Unclear instructions probably contribute to the suboptimal efficacy and adherence to topical agents in psoriasis.

Objectives  To analyse the quality of prescriptions for topical therapy in psoriasis and to determine factors associated with high-quality prescription writing.

Methods  We made a systematic analysis of 767 topical prescriptions written by dermatologists and general practitioners (GPs). The following parameters were recorded: writing mode (electronic vs. hand written), indication of formulation, frequency of administration, duration of treatment, indication of areas to be treated, and indication of amount of product to be used. We considered prescriptions of high quality to be those including at least four of the five prospectively defined quality parameters.

Results  Only 35·7% of prescriptions fulfilled the definition of a high-quality prescription. Quality of prescription writing was significantly influenced by two factors: electronic writing [odds ratio (OR) 3·04, 95% confidence interval (CI) 2·2–4·21; < 10−4] and specialty of the prescriber, dermatologists writing higher quality prescriptions compared with GPs (OR 1·61, 95% CI 1·54–2·14; < 10−4).

Conclusions  Almost two-thirds of topical prescriptions are not adequately written and do not include the required information to help patients manage their topical treatment in psoriasis correctly. The quality of topical prescriptions could be improved by making the use of electronic prescriptions widespread and by the development of aids for easy evaluation of the right amount of topical treatment to be applied according to body surface area involved.