Abstract Number: 48

Successful treatment of refractory type I pityriasis rubra pilaris with ustekinumab

N. Allen, A. Smith

Meeting: 2021 Dermcoll

Session Information

Date: -

Session Title: Poster Presentations

Session Time: -

Introduction: Pityriasis rubra pilaris (PRP) is a rare papu- losquamous disorder characterized by erythroderma, orange-red keratoderma and islands of sparing. There are
6 subtypes based on morphology, with the majority being type I adult PRP. Some cases go into spontaneous remission after 2–3 years. As PRP is a rare condition, there are not RCTs assessing treatment efficacy with treatment recom- mendations based on case reports and small case series.

Case: We report a case of treatment refractory PRP demonstrating initial complete response to ustekinumab. This case adds to the literature supporting biologic therapy in the setting of treatment resistant PRP.

A 70-year-old gentleman was referred to a tertiary hospital dermatology clinic for escalation of therapy in the setting of progressive erythroderma secondary to treatment refractory PRP. He was on 20 mg subcutaneous methotrexate at the time of presentation, having previously failed acitretin, ciclosporin and mycophenolate. Investigations for underly- ing malignancy, including CT-CAP were unremarkable. Screening investigations prior to biologic therapy revealed a positive Quantiferon gold. Accordingly, ustekinumab 45 mg was selected and commenced with concurrent isoniazid, in consultation with respiratory and infectious diseases teams. Tumour necrosis factor inhibitors (TNFi) were avoided due to the risk of reactivation of latent TB. Six months into treat- ment he has achieved complete clinical remission.

Conclusion: While TNF antagonists have the greatest evi- dence base for treatment resistant PRP, this case adds to the body of literature supporting IL12/23i in the setting of PRP, in instances where TNFi need to be avoided due to risk of infectious complications.