Abstract
BACKGROUND: Trigeminal autonomic cephalalgias (TACs) are characterized by unilateral headache with cranial autonomic symptoms. Sudden subtype changes may suggest secondary causes. CASE PRESENTATION: A 66-year-old woman presented with a rapid shift from paroxysmal hemicrania to SUNCT. Varicella zoster virus (VZV) reactivation was confirmed by CSF analysis and aqueous humor PCR. Ocular involvement included panuveitis and papillitis. Symptoms resolved after 14 days of intravenous acyclovir. CONCLUSION: Rapid TACs subtype transformation should prompt evaluation for secondary causes. Early diagnosis of VZV can lead to favorable outcomes.