Response to intravenous lidocaine in a patient with SUNCT syndrome.

Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) syndrome represents a serious therapeutic and diagnostic challenge, since it is usually refractory to most drugs and lacks biological markers. Response to intravenous lidocaine administration has been reported in some patients while it has failed in others. We report a patient with SUNCT syndrome who showed a clear-cut and consistent response to intravenous lidocaine therapy, which proved superior to placebo in a single-blinded fashion. Intravenous lidocaine should be considered in all patients with SUNCT syndrome. Response to this therapy could represent a diagnostic tool.