Harlequin syndrome is a rare disease. It is probable that the unilateral facial sympathetic nerve dysfunction leads to contralateral facial flushing. A 47-year-old male presented left nasal stuffiness, left facial flushing and painful swelling every afternoon for half a year. Physical examination was unremarkable. The magnetic resonance image showed mucosal thickening of the left sinuses in the afternoon; however, the computed tomography of nasal cavities and sinuses did not show any abnormality when he was uneventful in the morning. Steroid nasal spray, antihistamine, and analgesic were recommended. One month later, the left nasal stuffiness and left facial painful swelling subsided; however, the left facial flushing recurred every afternoon over the following two years. Therefore, the recurrent unilateral facial flushing and the ipsilateral rhinosinusitis may attribute to harlequin syndrome and vasomotor rhinitis. Conservative treatment is recommended.