Interferential current is effective in palmar psoriasis: an open prospective trial

Interferential current (LFC) has been shown to improve psoriasis in a small case series. So far no formal clinical trial had been conducted. As IFC is associated with slight prickling sensations a blinded study design was not feasible. Therefore, an open type prospective study was conducted with the assumption of 18% spontaneous remission rate. A response rate of 50% or le ss was judged as indicating no effect (hypothetical control), while 80% or more was considered as success (alternative hypothesis). In this "quasi-con trolled" study 12 patients with therapy resistant palmar psoriasis received local treatment with IFC during a 12 week period. Treatment was performed at low current density in two daily sessions, each of 6 minutes duration. E rythema, scaling, induration, fissures and pustules were recorded in separa te scores every 4 weeks. Response of a patient was judged positive when the total score of these criteria was reduced at least by two points at the en d of treatment. After 12 weeks of treatment, 11 of 12 patients were cured o r showed marked remission with the median overall score reduced by 4 points . An interim analysis was performed in order to decide whether the results had already reached significance (alpha < 0.05). The analysis revealed a st atistically significant response rate of 90% (95% confidence interval 62-99 %). These results are highly encouraging and should focus attention on this new therapy modality, which, in contrast to other treatments is not associ ated with side effects and discomfort.