Dermatitis bullosa caused by the immune checkpoint inhibitor camrelizumab: A case report
Authors: Jiang Yuan-Jing , Wu Lu , Yang Xiao , Pu Yu , Ning Bing-Jie , Peng Na , Zhu Xiao-Ju 
Published: December 2024

BACKGROUND
Since the advent of the 20th century, alongside the progression of medical science and technological advancements, immunotherapy has emerged as a pivotal therapeutic approach for tumor patients subsequent to undergoing radiotherapy and chemotherapy. Arimab (camrelizumab), a flagship drug in the realm of immunotherapy, functions as a monoclonal antibody specifically targeting the programmed death protein 1 (PD-1). This drug engages with the human PD-1 receptor, effectively inhibiting the PD-1/programmed death ligand 1 signaling pathway. This inhibition results in the restoration of T cell activity and the induction of an anti-tumour response. However, it is noteworthy that such interference could lead to immune-related adverse events resembling autoimmune reactions. The growing availability and clinical use of immune checkpoint inhibitors have raised significant clinical concerns regarding their safety. Numerous instances of immune-related adverse reactions and the associated management strategies have been extensively reported. Timely identification and diagnosis, coupled with multidisciplinary consultation and the prompt administration of immunosuppressants, can effectively address severe immune-related adverse reactions.
CASE SUMMARY
Arimab (camrelizumab), a monoclonal antibody targeting programmed death protein 1 (PD-1), disrupts the PD-1/ programmed death ligand 1 (PD-L1) interaction, reactivating T cell function and triggering anti-tumor immunity. However, this disruption may trigger immune-mediated adverse events akin to autoimmune disorders. Approximately 2.8% of such events manifest as immune-related dermatologic reactions, with 0.7% classified as grade 3, which are infrequently documented. Here, this study describes a case of grade 3 bullous dermatitis occurring 15 days after initiating camrelizumab therapy. The patient, a 67-year-old male with oesophageal squamous cell carcinoma, received camrelizumab plus paclitaxel alongside chemotherapy and radiotherapy in early 2022. Due to disease progression, maintenance monotherapy with camrelizumab (200 mg) commenced in June 2022. On the fourth cycle, 15 days into treatment, the patient presented with an immune-checkpoint inhibitor-related rash, despite unremarkable test results. Dermatology and pharmacy consultations were conducted, leading to glucocorticoid therapy, topical interventions, and supportive care. Gastric mucosal protection, nutritional supplementation, and other adjunctive treatments were also provided. The patient's symptoms resolved within 15 days post-discharge, resulting in discontinuation of camrelizumab. Like other PD-1 inhibitors, camrelizumab is associated with immune-mediated dermatitis. Thus, optimal management of these events requires a multidisciplinary approach, vigilant monitoring, regular evaluations, prompt glucocorticoid administration, and specialized dermatologic care.
CONCLUSION
The increasing adoption of immune checkpoint inhibitors in clinical practice has prompted substantial concerns about their safety profile. A wide range of immune-related adverse events and corresponding management strategies have been well-documented. Early recognition and accurate diagnosis, combined with interdisciplinary collaboration and swift initiation of immunosuppressive therapy, are essential in managing severe immune-related adverse reactions effectively. This report details the treatment trajectory and outcome of a case involving immune-related cutaneous adverse reactions, providing pertinent clinical insights for future cases.