BACKGROUND: Harlequin syndrome (HS) is a rare clinical manifestation characterized by unilateral sweating and flushing of the face, neck, upper chest, and/or arm, which results from a dysfunction of the autonomic nervous system. Symptoms may worsen with heat, stress, strenuous exercise, or emotional reactions. The syndrome is also associated with traumatic or vascular injuries, tumors, or complications from medical procedures, such as radiofrequency ablation (RFA), surgery, intravenous cannulation, among others.

CASE REPORT: A 41-year-old woman with trigeminal neuralgia of the right maxillary and mandibular branches underwent RFA treatment. While the pain resolved completely following the procedure, the patient developed hemifacial flushing and mild sweating (HS). The facial flushing was successfully treated using botulinum neurotoxin type A injections (100 units), with an 80% improvement. A brain magnetic resonance imaging was ordered, which revealed no significant abnormalities that could account for the patient’s clinical signs and symptoms.

CONCLUSIONS: This case underscores the importance of a multidisciplinary follow-up approach for the identification and management of autonomic nervous system complications after ablative procedures of the trigeminal ganglion.

KEYWORDS: Harlequin syndrome, ablation, botulinum neurotoxin type A, radiofrequency, trigeminal neuralgia