Loss of Smell (Anosmia)

Loss of smell can be an early prodromal marker for Parkinson's disease (preceding motor symptoms by 5-10 years), post-viral anosmia, or nasal pathology. Smell testing is now part of Parkinson's screening.

Body System: Neurological

Related Diseases

• Parkinson's Disease — Anosmia/hyposmia affects 90% of PD patients and precedes motor symptoms by 5-10 years. It reflects alpha-synuclein pathology in the olfactory bulb.
• Alzheimer's Disease — Smell identification deficits correlate with entorhinal cortex atrophy and predict conversion from MCI to AD.

Related Compounds

• Ambroxol
• Lion's Mane

Frequently Asked Questions

Is loss of smell an early sign of Parkinson's?

Yes — hyposmia is present in 90% of PD patients and is now recognized as a key prodromal marker. The UPSIT (University of Pennsylvania Smell Identification Test) is used in research to identify at-risk individuals. Combined with REM behavior disorder and constipation, anosmia identifies individuals with >80% probability of developing PD within 10 years.