Reduced sense of smell can have various causes, ranging in severity from 'worrying' to 'generally fatal'. Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.
Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms. In order to diagnose reduced sense of smell, we could:
Cause | Probability | Status |
---|---|---|
Schizophrenia | 96% | Confirm |
Cigarette Smoke Damage | 22% | Unlikely |
Vitamin A Need | 19% | Unlikely |
Nasal Polyps | 3% | Ruled out |
Sarcoidosis | 3% | Ruled out |
Premature Aging | 2% | Ruled out |
Megaloblastic Anemia | 2% | Ruled out |
Parkinson's Disease | 2% | Ruled out |
Has your sense of smell declined within the past few years, for reasons other than nasal congestion?
Possible responses:
→ Don't know→ No, my sense of smell has remained about the same → Yes, but it is due to ongoing nasal congestion → Yes, it is somewhat worse now → Yes, it is a lot worse now |
Reduction of the sense of smell has been identified as an early sign of Alzheimer's disease since the 1970s.
Specifically, tumors of the frontal lobe.
Intranasal drug use can cause a loss of the sense of smell.
Toxins – especially acrylates, methacrylates and cadmium – can cause a reduction in the sense of smell.
[Kieff, D; Boey, H; Schaefer, P; Goodman, M; Joseph, M (1997). "Isolated neurosarcoidosis presenting as anosmia and visual changes". Otolaryngology – Head and Neck Surgery 117 (6): pp183-6]
[Rupp, Claudia I.; Fleischhacker, W. Wolfgang; Kemmler, Georg; Kremser, Christian; Bilder, Robert M.; Mechtcheriakov, Sergei; Szeszko, Philip R.; Walch, Thomas et al (2005). "Olfactory functions and volumetric measures of orbitofrontal and limbic regions in schizophrenia". Schizophrenia Research 74 (2-3): pp149-61]
Zinc deficiency is rare in the developed world, but it can cause impaired sense of smell or taste.