What is the treatment for COVID-19-related loss of smell (anosmia)?

Treatment for COVID-19-Related Loss of Smell (Anosmia)

Due to its simplicity and safety, olfactory training should be recommended as the primary treatment for all patients with COVID-19-related loss of smell persisting beyond 2 weeks. 1

Understanding COVID-19 Anosmia

COVID-19-related anosmia is a common symptom affecting approximately 53% of infected individuals. It may occur as an isolated symptom, an early presenting symptom, or part of mild flu-like symptoms. The pathophysiology likely involves:

• Inflammation of the olfactory cleft
• Damage to the olfactory epithelium
• Possible involvement of the olfactory central nervous system
• Loss of cilia of the olfactory sensory neurons

Treatment Algorithm

First-line Treatment:

• Olfactory training: Recommended for all patients with persistent loss of smell beyond 2 weeks 1, 2
  • Involves repeated exposure to different odors (typically 4 distinct scents)
  • Should be performed twice daily for at least 12 weeks
  • All 11 studies evaluating olfactory training showed benefit of the intervention 1

Optional Treatments (individualized basis):

1. Intranasal corticosteroids:

   • May be considered on an individual basis 1, 2
   • However, evidence shows no superiority over olfactory training alone 3
   • A randomized controlled trial of 100 patients found mometasone furoate nasal spray with olfactory training showed no significant difference compared to olfactory training alone 3

2. Oral corticosteroids:

   • May be considered on an individual basis 2
   • Limited evidence for effectiveness
   • Should be used cautiously due to potential side effects

3. Omega-3 supplements:

   • May be considered on an individual basis 2
   • Limited evidence for effectiveness

Not Recommended:

• Alpha-lipoic acid: Not recommended based on consensus guidelines 2

Patient Education and Expectations

• Discuss the likelihood of spontaneous recovery with patients 1

  • Most patients recover fully or partially within 6 months 4
  • Recovery time varies significantly between individuals
  • Approximately 44% of patients may have at least one other ongoing symptom at 6 months 4

• Inform about potential development of parosmia (distorted smell perception)

  • Occurs in approximately 43% of patients
  • Typically develops around 2.5 months after initial smell loss 4

Special Considerations

• Smoking cessation: Should be recommended for all patients with anosmia, although the direct benefit for COVID-19 anosmia is not clearly established 1

• Monitoring for other symptoms: Fatigue is the most common persistent symptom accompanying anosmia 4

When to Refer

• Consider referral to an otolaryngologist if:
  • No improvement after 3 months of olfactory training
  • Symptoms worsen despite treatment
  • Unilateral symptoms or other concerning features suggesting alternative diagnoses

Important Caveats

• Most interventions for COVID-19-related anosmia have limited high-quality evidence
• Physicians should emphasize that many patients recover spontaneously over time
• Other interventions beyond olfactory training should generally be reserved for clinical trials 1
• The prevalence of anosmia varies among age categories and between sexes 5

By following this approach, clinicians can provide evidence-based management for patients with COVID-19-related anosmia while acknowledging the limitations of current treatment options.