Emerging Role of Biologic Drugs Targeting IL-17 and IL-23: Pityriasis Rubra Pilaris

Pityriasis rubra pilaris (PRP) is a rare, papulosquamous, inflammatory skin disease. PRP represents a therapeutic challenge. The rarity of this disease and its possible spontaneous remission makes the conduction and interpretation of therapeutic studies particularly difficult. Moreover, PRP not infrequently proves resistant to common topical and conventional systemic therapies. In this context, numerous biologic agents have been reported in PRP treatment. The aim of our manuscript was to review the current literature to evaluate the possible role of biologics targeting the IL17/23 axis in PRP management. Recent cases in the literature have highlighted the use of several promising drugs: IL-17 inhibitors, IL-23 inhibitors, and the IL-12/23p40 inhibitor ustekinumab. However, it should be noted that all these drugs are approved for moderate-to-severe plaque psoriasis and their use in PRP is off label. The treatment of PRP is based on clinical experience, case reports or case series reported in the literature, as randomized controlled trials are difficult to conduct due to the rarity of the condition. Despite data on the efficacy of drugs targeting IL-17 and IL-23 being promising, they are still limited. Certainly, further studies are desirable to better characterize PRP and establish shared guidelines.