Carbamazepine-Induced Systemic Lupus Erythematosus in a Patient With Idiopathic Trigeminal Neuralgia: A Case Report.

A 50-year-old woman presented with a mandibular second molar and facial pain and was diagnosed with idiopathic trigeminal neuralgia. Carbamazepine (CBZ) was initiated at 300 mg/day, successfully relieving the pain. However, on the 8th day of CBZ treatment, the patient developed symptoms resembling those of systemic lupus erythematosus with malaise, nausea, and facial erythema. CBZ was immediately discontinued. Subsequently, she experienced numbness in both lower limbs and mild fever, which resolved within a few days. Laboratory tests revealed leukopenia (2.8 × 10/μL), elevated C-reactive protein levels (0.46 mg/dL), and the presence of antinuclear antibodies (ANA) and anti-Sjögren's syndrome-related antigen A antibodies. The clinical course suggested CBZ-induced drug-induced lupus erythematosus (DILE). This case highlights the possibility of DILE onset even after short-term CBZ treatment, the importance of prompt discontinuation of the causative drug in patients suspected of DILE, and the conduct of ANA testing in diagnosing DILE.