Bullous lichen planus and anti-programmed cell death-1 therapy: Case report and literature review.

BACKGROUND: Cutaneous adverse effects of immunotherapies are being seen with increasing frequency in general practice. While anti-PD1 lichenoid reactions are well known, only a few cases of bullous lichen planus have so far been reported in the medical literature. Herein we described a case of secondary bullous lichen planus associated with nivolumab and we present a systematic review of all anti-P1-induced cases reported in the literature. PATIENTS AND METHODS: Three months after beginning treatment with nivolumab for metastatic clear-cell renal carcinoma, a 68-year-old man presented pruritic purplish papules on his limbs that subsequently became bullous. Clinical-histological correlation led us to a diagnosis of secondary bullous lichen planus induced by nivolumab. Systemic steroids and withdrawal of immunotherapy resulted in clinical improvement. REVIEW OF THE LITERATURE: Our systematic review revealed 20 cases of lichen planus induced by anti-PD1 (nivolumab and pembrolizumab) published between 2016 and 2018, 6 of which were of the bullous form. Treatment and maintenance or discontinuation of anti-PD1 were dependent on severity. DISCUSSION: Bullous lichen planus has been reported only rarely in the context of nivolumab therapy. The timeline for development of cutaneous adverse reactions under anti-PD1 immunotherapy may last weeks or months and regular monitoring is required. Withdrawal of immunotherapy should only be considered where the outcome under systemic corticosteroids is unfavourable.