Romosozumab‐Associated Oral Lichenoid Drug Reaction in a Postmenopausal Woman: A Case Report

Oral lichenoid drug reactions (OLDRs) are uncommon adverse reactions associated with various medications, including monoclonal antibodies. Romosozumab, a humanized monoclonal antibody targeting sclerostin, has emerged as an effective treatment for osteoporosis due to its dual action of increasing bone formation and reducing bone resorption. However, its safety profile continues to be explored. This case report describes a rare instance of OLDRs associated with romosozumab therapy in a postmenopausal patient undergoing treatment for osteoporosis. The patient presented with symptomatic oral mucosal lesions characterized by white reticular striae, erythematous patches, and ulcerations, clinically and histologically consistent with OLDRs. The temporal association between the initiation of romosozumab therapy and lesion onset, together with complete remission following completion of the planned 12‐month treatment course, supports a probable association. This case highlights the importance of recognizing OLDRs as a potential adverse effect of romosozumab and underscores the need for clinicians to perform thorough oral examinations in patients reporting mucosal discomfort during treatment. Further research is necessary to elucidate the underlying mechanisms and incidence of this adverse reaction.