A decrease or loss of smell can occur from a number of causes. Sometimes the patient may not be aware of the loss or its impact.


Evaluation of the patient should include questions about:

(1) the quality of smell in the past

(2) the extent of loss in the sense of smell

(3) what can and cannot be smelled

(4) transient versus permanent loss

(5) past occupational and medical history


Differential diagnosis of a loss of smell includes:

(1) advancing age

(2) Parkinson's or Alzheimer's disease

(3) significant occupational exposure to chemicals, smoke or dust

(4) smoking

(5) allergic or nonallerigc rhinosinusitis with or without nasal polyps

(6) acute viral infection

(7) head and/or nasal trauma

(8) medications (see previous section)

(9) epilepsy

(10) deviated nasal septum

(11) stroke

(12) cancer therapy (chemoradiation)

(13) facial, nasal or cranial surgery

(14) diabetes mellitus


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