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.

The COVID-19 pandemic has encouraged the rapid development and licensing of vaccines against SARS-CoV-2. Currently, numerous vaccines are available on a global scale and are based on different mechanisms of action, including mRNA technology, viral vectors, inactive viruses, and subunit particles. Mass vaccination conducted worldwide has highlighted the potential development of side effects, including ones with skin involvement. This review synthesizes data from 62 manuscripts, reporting a total of 142 cases of autoimmune blistering skin diseases (AIBDs) following COVID-19 vaccination, comprising 59 cases of pemphigus and 83 cases of bullous pemphigoid. Among the 83 bullous pemphigoid cases, 78 were BP, with additional cases including 2 oral mucous membrane pemphigoid, 1 pemphigoid gestationis, 1 anti-p200 BP, and 1 dyshidrosiform BP. The mean age of affected individuals was 72 ± 12.7 years, with an average symptom onset of 11 ± 10.8 days post-vaccination. Notably, 59% of cases followed vaccination with BNT162b2 (Pfizer-BioNTech), 51.8% were new diagnoses, and 45.8% occurred after the second dose. The purpose of our review is to analyze the cases of pemphigus and bullous pemphigoid associated with COVID-19 vaccination and to investigate the pathogenetic mechanisms underlying the new development or flare-up of these diseases in association with vaccination. Our results show that the association between COVID-19 vaccines and AIBDs is a possible event.