Abstract: Objective: To evaluate the efficacy and safety of biological agents or small molecular targeted drugs in the treatment of refractory pityriasis rubra pilaris(PRP). Methods: A retrospective analysis was conducted on the clinical data of PRP patients who visited our hospital from January 2020 to December 2023. All patients had received systematic treatment but the effect was not satisfactory. Therapeutic drugs in this study included secukinumab, tofacitinib citrate or apremilast treatment. The therapeutic effect was evaluated by the psoriasis Lesion Area and Severity Index (PASI) score. The onset time of treatment, the rate of reaching the target, the final improvement rate and adverse reactions were recorded. Results: A total of six patients were analyzed, among whom one was treated with secukinumab, two with tofacitinib citrate, one with apremilast, and two with apremilast combined with acitretin. At 4 weeks of treatment, 4 cases achieved PASI50. During the follow-up period of 32-54 weeks, 2 patients achieved PASI 90, 4 reached PASI 75. No serious adverse reactions occurred in all patients. Conclusions: Biological agents and small molecule targeted drugs have significant efficacy and good safety in the treatment of refractory PRP.

Key words: pityriasis rubra pilaris, secukinumab, tofacitinib, apremilast