Phantosmia (Phantom Smell)


Phantosmia is the term that describes olfactory hallucinations also known as phantom smells. People will often report smelling a burnt, oily, or metallic odor that is not there and is one of the earliest mystery symptoms of Superficial Siderosis pre-diagnosis. Olfactory receptors in your brain transform the chemical signatures of scents into electrical signals (as opposed to physical nerve signals). An odor molecule binds to the olfactory receptors in the nasal mucosa that line your nostrils. This binding action triggers neurons to send messages to your brain. Your olfactory nerve(first cranial nerve) carries these signals directly to the frontal lobe.

Our brain categorizes odors into two categories: good and bad. Pleasant smells activate serotonergic systems to release oxytocin allowing us to feel good, happy, and satisfied. Foul smells activate the dopaminergic system, norepinergic system, and epinergic system. These systems kick in a fight-or-flight reaction causing a person to feel repulsed, bad, or upset.

This disorder is similar to tinnitus. A large percentage of Superficial Siderosis patients who experience phantosmia progress to anosmia.


Updated: October 31, 2020

Sources: Superficial siderosis is a rare neurologic disease characterized by progressive sensorineural hearing loss, cerebellar ataxia, pyramidal signs, and neuroimaging findings revealing hemosiderin deposits in the spinal and cranial leptomeninges and subpial layer. The disease progresses slowly, and patients may present with mild cognitive impairment, nystagmus, dysmetria, spasticity, dysdiadochokinesia, dysarthria, hyperreflexia, and Babinski signs. Additional features reported include dementia, urinary incontinence, anosmia, ageusia, and anisocoria. Superficial siderosis MedGen UID: 831707 •Concept ID: CN226971 •Finding Orphanet: ORPHA247245
Living With SuperficialSiderosis Website PubMed Reference Library 
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