Dupilumab-Induced Generalized Lichen Planus: A Case Report

Hui-shang Feng,1,2 Chuang Zhang,3 Yang Guo,1 Yuan-ning Jia,1 Ye Zhai,1 Xiao-ran Zheng,1 Tai Zhang,4 Bao-chen Zhu,4 Wan-tong Zhang,5 Guo-dong Hua4 1Department of Dermatology, Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, People’s Republic of China; 2Second Clinical Medical School, Beijing University of Chinese Medicine, Beijing, People’s Republic of China; 3Department of Dermatology, Peking University First Hospital, Beijing, People’s Republic of China; 4Department of Pharmacy, Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, People’s Republic of China; 5Institute of Clinical Pharmacology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, People’s Republic of ChinaCorrespondence: Bao-chen Zhu, Department of Pharmacy, Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, 100700, People’s Republic of China, Email [email protected] Wan-tong Zhang, Institute of Clinical Pharmacology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, 100091, People’s Republic of China, Email [email protected]: Lichen planus (LP) is a chronic inflammatory skin disease of unknown cause. Common subtypes include generalized LP, linear LP, annular LP, and hypertrophic LP. Current clinical evidence suggests that lichen planus is a T-cell-mediated autoimmune disorder. Therefore, an increasing number of clinicians are opting for biologics or immunomodulators to manage lichen planus, but the reported evidence on their efficacy and safety remains limited.Case Summary: This case report describes a 32-year-old female with pre-existing localized lichen planus (LP) who developed generalized LP after IL-4Rα inhibitor dupilumab therapy. Following three dupilumab injections, progressive dissemination of pruritic pink-to-flesh-coloured or light-brown papules to the trunk and limbs was observed. The lesions regressed upon dupilumab discontinuation and pharmacological intervention. Diagnosis was confirmed by dermoscopy and histopathology.Conclusion: A temporal correlation and Naranjo adverse drug reaction score of 8 indicated dupilumab as the trigger, likely via Th1/Th2 immune deviation. This first-documented paradoxical reaction underscores dupilumab’s potential to trigger generalized LP through immune deviation.Plain Language Summary: What’s already known about this topic?Dupilumab is a well-established IL-4Rα inhibitor that safely improves multiple type-2 inflammatory diseases, and existing small series have documented its use either to treat lichen planus or to cause de-novo lichen planus when prescribed for other indications.Paradoxical worsening of lichen planus after dupilumab has not previously been reported.What does this study add?This report details the first documented case in which dupilumab, given to treat pre-existing localized lichen planus, precipitated generalized lichen planus after only three injections.It provides a high-certainty causality assessment (Naranjo score 8) and emphasizes the need for close monitoring for paradoxical immune deviation when dupilumab is used in patients with lichen planus.Keywords: lichen planus, IL-4Rα inhibitor, dupilumab, immune deviation, adverse drug reaction