Management of Persistent Loss of Taste and Smell Following COVID-19
Olfactory training should be initiated immediately and continued for at least 3-6 months as the primary treatment for persistent post-COVID taste and smell loss. 1, 2
Initial Assessment and Diagnosis
Obtain objective testing rather than relying on patient self-report, as patients commonly underestimate their impairment severity—objective testing reveals dysfunction in 98.3% of patients even when only 35% report symptoms. 3, 2
- Perform validated psychophysical testing using UPSIT (University of Pennsylvania Smell Identification Test) or Sniffin'Sticks, which take 4-25 minutes to administer and have high test-retest reliability. 1, 2
- Conduct rigid nasal endoscopy to differentiate between conductive (nasal obstruction) and sensorineural causes. 2
- Document temporal relationship to COVID-19 infection, associated nasal symptoms (though traditional congestion/rhinorrhea are often absent in COVID-19), and predisposing factors like nasal polyps or asthma. 3, 2
Key clinical distinction: Most "taste loss" actually reflects loss of retronasal olfaction (flavor perception) rather than true taste dysfunction. 3
Primary Treatment Approach
Start olfactory training immediately upon diagnosis and continue for a minimum of 3-6 months. 1, 2
- Direct patients to validated resources for proper technique, such as www.fifthsense.org.uk. 2
- This is the only intervention with consistent guideline support for post-viral olfactory dysfunction. 4
Additional Treatment Considerations
Topical corticosteroids combined with olfactory training showed no significant benefit over olfactory training alone in the highest quality RCT (62% vs 52% recovery, p=0.31), so routine use is not recommended. 4
Intranasal insulin showed significantly higher olfactory detection scores (p=0.0163) in one small RCT, but this requires further validation before routine recommendation. 4
Refer to a registered dietitian for counseling on flavor enhancement, additional seasoning, avoiding unpleasant foods, and expanding dietary options to maintain nutrition. 1, 2
Expected Recovery Timeline
Most patients recover within 1-2 months, but recovery is variable and some develop permanent dysfunction:
- 73% improve within 7-14 days of onset. 3
- 44-73% recover within the first month. 1, 2
- 88% recover by 2 months (median 11.5 days). 5
- However, 15.6% still have ongoing smell loss and 8% have ongoing taste loss at 12-14 months. 6
- 43.1% develop parosmia (distorted smell) at median 2.5 months after initial loss. 7
Follow-Up Protocol
Re-evaluate at 1 month, 3 months, and 6 months after initiating treatment with repeat objective psychophysical testing to document changes. 1, 2
Refer to an otolaryngologist or specialized smell/taste clinic if no improvement occurs after 3-6 months of olfactory training. 1, 2
When to Order Advanced Imaging
Order CT and MRI of skull base and brain only when psychophysical testing severity does not correlate with endoscopic findings, raising suspicion for occult sinonasal or skull base tumor—not routinely indicated when there is clear temporal relationship to viral infection. 1, 2
Critical Safety Counseling
Address safety concerns related to inability to detect spoiled food, gas leaks, or smoke, as these pose real-world risks to patients with persistent chemosensory dysfunction. 1
Common Pitfalls to Avoid
- Do not rely on patient self-assessment of severity—objective testing is mandatory. 3, 2
- Do not assume taste loss is true gustatory dysfunction—it is usually retronasal olfactory loss. 3
- Do not order unnecessary neuroimaging when there is clear temporal relationship to COVID-19 infection. 1
- Do not assume recovery patterns are uniform—different taste qualities and chemesthetic sensations (like oral burn from spicy foods) recover at different rates and may be dyssynchronous. 8