assessment of anosmia in primary care

Last edited 03/2021 and last reviewed 03/2021

History (1,2)

• history of olfactory should include:
  • duration of symptoms
    • should evaluate how the disorder started, for example, suddenly, after a trauma or a (severe) cold, which then makes a post-traumatic disorder or a disorder after an upper respiratory tract infection (post-URTI), very likely
    • gradual onset and difficulties in recalling a triggering event also might suggest age-related, idiopathic disorder, or disorder due to a neurodegenerative disease
    • if the patient has difficulties recalling the exact moment the disorder began and describes olfactory fluctuations, sinonasal disorders are more likely (2)
    • patients suffering from neurodegenerative diseases also describe the smell loss as either 'gradually diminishing' or as 'gone' but rarely as fluctuating
  • taste disturbance
    • because individuals may respond differently to the olfactory impairment, it is importan to assess the impact of perceived and/or measured impairment on the patient's eating behaviors and nutritional status (2)
  • nasal discharge (mucous, purulent, cerebrospinal fluid)
  • preceding events (head trauma, recent upper respiratory tract infection/viral symptoms)
  • previous sinonasal surgery
  • use of recreational drugs (including alcohol and tobacco)
  • medication review - current and recent medication
  • chronic medical conditions (especially diabetes, renal or hepatic dysfunction, Alzheimer’s disease, and Parkinson's)
  • rhinological symptoms (facial pain/ pressure, epistaxis, nasal obstruction)
  • neurological symptoms (headaches, seizures)
  • social factors
    • loss of the ability to smell (unpleasant) odors can greatly impact personal hygiene
    • patients can exaggerate their personal hygiene, for example, by showering several times a day or excessive use of perfume or aftershave - a patient may consider that an olfactory impairment affects their relationship with their partner, friends, and family

Always consider red flag features

red-flag symptoms for olfactory dysfunction include (1):

• unilateral nasal symptoms
• bleeding
• crusting/scabbing within the nasal cavity
• cacosmia (perceived malodorous smell)
• orbital symptoms (swelling, visual symptoms, or ophthalmoplegia)
• severe frontal headaches
• frontal swelling
• the onset of new neurological/meningitic symptom

Examination in primary care

• general examination of undertaken of the external nose for signs of trauma and gross nasal deformity;
• examination of the entry to the nasal cavity may reveal nasal discharge, deviated nasal septum, nasal polyps or masses, foreign bodies, or signs rhinitis
• neurological examination is guided by the history
  • cranial nerve examination focusing on the optic nerve, trigeminal nerve, and facial nerve may be indicated; fundoscopy for signs of raised intracranial pressure
  • memory assessment and examination for signs of Parkinson's disease may be indicated

Reference:

• Deutsch PG et al. Anosmia: an evidence-based approach to diagnosis and management in primary care British Journal of General Practice 2021; 71: 135-138. DOI: https://doi.org/10.3399/bjgp21X715181
• Boesveldt S et al. Anosmia- A Clinical Review Chem Senses. 2017 Sep; 42(7): 513–523.