Pityriasis rubra pilaris (PRP) is a rare chronic inflammatory dermatosis. Treatment is challenging and mostly based on scarce empirical evidence from large case series.

To investigate patient characteristics and therapy outcomes in patients with PRP.

In this retrospective study, patients with PRP treated at the Department of Dermatology, University Medical Center Göttingen, between 01/2005 and 10/2018, were analysed according to patient and disease characteristics and treatment experience.

PRP was diagnosed in 28 patients with a mean age of 57.3 years at onset; 20 were men (71.4%) and eight women (28.6%). Of all the patients, 89.3% had comorbid diseases; metabolic disorders were particularly frequent. Seventy-eight treatment courses were identified with acitretin as the most common therapy (28.2%). Excellent response was noted in 71.4% of treatment courses with methotrexate, followed by cyclosporine (27.3%) and acitretin (19.0%). Among biologics, ustekinumab (excellentresponse: 75.0%) and infliximab (50.0%) were particularly effective.

This study is one of the few comprehensive larger case series of patients with PRP. Acitretin may be effective, particularly for type I PRP, and other retinoids, methotrexate or cyclosporine might also be considered early in the therapeutic algorithm. Moreover, our data adds to the growing evidence that biologics are effective and safe for the treatment of PRP.