Ustekinumab as an alternative treatment option for chronic pityriasis rubra pilaris.

Pityriasis rubra pilaris (PRP) is an exceptionally rare, chronic inflammatory dermatosis of unknown etiology. Patients classically present with small, follicular keratosis and salmon-colored plaques that begin at the head and neck and slowly progress to widespread erythroderma including the palms and soles. It is difficult to distinguish PRP from other inflammatory dermatoses; however, features that help aid in the diagnosis include 'islands' of spared skin, orangish hue and typical findings on biopsy. There are no specific guidelines on therapy and treatment options include corticosteroids, vitamin D analogs, retinoids, methotrexate, cyclosporine, azathioprine and tumor necrosis factor alpha antagonists. Unfortunately options are limited for patients when these drugs do not work. We report a case of chronic PRP, refractory to conventional treatment, successfully treated with ustekinumab monotherapy. The patient was treated with 90 mg subcutaneous ustekinumab injections and began to show improvement within only 8 weeks. Long-term control of the disease has been attained without any significant side effects. We report this case to show that ustekinumab can be used as an alternative treatment method for patients with chronic, unremitting PRP. Treatment response is remarkably rapid and the infrequent dosing leads to patient compliance and a significantly improved quality of life.