Primary care management of anosmia

Management (1,2):

• indications for referral to secondary care include patients with any 'red flag' symptoms or >6 weeks of olfactory dysfunction (1)
  • 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
  • however if the symptoms coincide with symptoms of COVID-19 infection
    • referral should be made after 3 months to allow spontaneous resolution
  • also where a patient has an atypical presentation or has not responded to initial treatment, this would be an indication for referral to secondary care

Treatment will depend on cause

• in primary care majority of causes related to a primary nasal pathology (e.g. chronic rhinosinusitis, allergic rhinitis, acute sinusitis)
  • intranasal corticosteroids added to disease-specific treatments are the mainstay of treatment
  • in cases of anosmia persisting for >2 weeks, a trial of intranasal corticosteroids should be instigated
    • can be augmented by a course of more potent steroid drops and nasal saline douching at the clinician's discretion
    • oral corticosteroids may lead to resolution of olfactory disturbance in chronic rhinosinusitis; also some possible improvement degree in post-viral anosmia (although the evidence is less strong in this case)
  • recommendations for management of COVID-19-associated anosmia (1)
    • consider a short course of high-dose oral steroids after 2 weeks for persistent symptoms, following resolution of other symptoms related to COVID-19
  • if anosmia is thought to be idiopathic or post-viral, there have been suggestions of various different dietary supplements
    • include zinc, alpha lipoic acid, vitamin a, and omega
    • evidence for their efficacy is poor and does not support their use
  • further imaging is via secondary care
    • in context of suspected cause e.g. MRI may be undertaken to exclude intracranial pathologies such as anterior cranial fossa tumours or demyelinating conditions
  • if no surgical treatment is required and there has been failure of medical management then referral a dedicated smell clinic for olfactory retraining is 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.