Phantosmia, aka Phantom Smell, is smelling an odor that is not really there. Phantosmia is often the first sign of Superficial Siderosis sense of smell problems.

Olfactory receptors in your brain transform the chemical signatures of odors 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 triggers neurons to send messages to your brain. Your olfactory nerve, aka the first cranial nerve, carries these signals directly to the frontal lobe.

Our brain categorizes odors into two categories: good and bad. Good smells activate serotonergic systems to release oxytocin. We feel good, happy, and satisfied. Bad smells activate the dopaminergic system, norepinergic system, and epinergic system. These systems kick in our fight-or-flight reaction. We feel bad, scared and repulsed.

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



Updated: June 16, 2018

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
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