• Phantosmia;
  • hallucination;
  • olfaction;
  • smell


Objectives/Hypothesis Idiopathic olfactory hallucination is a rare condition. We report two cases of idiopathic olfactory hallucination and a review of the literature that relates to this condition.

Study Design A retrospective case study of two patients with idiopathic olfactory hallucination.

Methods Records of two patients were retrospectively reviewed.

Results The diagnosis of idiopathic olfactory hallucination was confirmed after excluding any intranasal disease or any central nervous system disorder discernible by an electroencephalogram and magnetic resonance imaging. Both patients were successfully treated with sodium valproate. One patient stopped taking sodium valproate because of side effects, only for the symptoms to return, but these were then controlled by phenytoin sodium. The mean patient follow-up time was 3 years 5 months.

Conclusions The symptoms of some cases of idiopathic olfactory hallucination may be controlled by sodium valproate or phenytoin sodium. We hypothesize that this disorder may be a central phenomenon attributable to reverberating circuits.