Phantosmia

In addition, phantosmias or, in essence, olfactory hallucinations have been described in association with seizure activity, psychiatric illness, and Alzheimer's Disease.

Most often, phantosmias occur after trauma or URTI and consist of unpleasant odors occurring without being elicited through environmental odor sources.

Patients with phantosmia thought to be related to abnormal olfactory signal processing will often confirm a unilateral presentation to the distorted smell when asked.