Drug-Induced Lupus Erythematosus After 14 Years of Carbamazepine Use in a Patient With Neuromyelitis Optica Spectrum Disorder: A Case Report.

BACKGROUND Carbamazepine (CBZ) is a common therapy for seizures, neuropathic pain, and painful tonic spasms following spinal cord disease; however, it is associated with rare autoimmune complications, including drug-induced lupus erythematosus (DILE). Diagnosis of DILE can be challenging, especially when onset occurs after a prolonged latency period. Neuromyelitis optica spectrum disorder (NMOSD), an autoimmune disease characterized by recurrent inflammation of the central nervous system, frequently coexists with other autoimmune disorders. This report describes a case of DILE in a 61-year-old woman with NMOSD involving the cervical and thoracic spinal cord after 14 years of CBZ therapy. CASE REPORT A 61-year-old woman with aquaporin-4-IgG-positive NMOSD involving the cervical and thoracic spinal cords had received CBZ for 14 years to control painful tonic spasms. She presented with fatigue, weight loss, intermittent fever, and pleural effusion. Laboratory testing showed a high antinuclear antibody titer (1: 640) and elevated anti-single-stranded DNA, anti-DNA, and anti-histone antibodies. Chest imaging demonstrated pleural effusion and pleural thickening; malignancy and infection were excluded. Discontinuation of CBZ led to resolution of symptoms, normalization of inflammatory markers, and a decline in lupus-related autoantibodies, confirming the diagnosis of DILE. No recurrence was observed during a 30-month follow-up period. CONCLUSIONS This report describes a rare delayed-onset autoimmune adverse effect of CBZ that developed 14 years after treatment initiation. It highlights the importance of clinical awareness of potential autoimmune associations, particularly when CBZ is used in patients with preexisting autoimmune disorders such as NMOSD.