Can loss of smell and taste occur with a common cold or flu?

Loss of Smell and Taste in Common Cold and Flu

Yes, loss of smell and taste can occur with common cold and flu, though it is more commonly associated with COVID-19 infection. While olfactory dysfunction is reported in approximately 11% of viral upper respiratory infections, it is much more prevalent and pronounced in COVID-19 cases 1.

Prevalence and Characteristics in Different Respiratory Infections

• Loss of smell (anosmia) and taste (ageusia) can occur in both common cold and influenza, but is typically less common and less severe than in COVID-19 2
• In COVID-19, olfactory dysfunction is reported in 59-98% of patients, making it a hallmark symptom 1
• In non-COVID viral respiratory infections, patient reports of "taste loss" often stem from confusion between taste and flavor perception, as true taste loss is relatively rare in common cold and flu 2

Timing and Presentation

• In common cold, symptoms typically last 10-14 days in children and less than a week in adults 3
• When smell/taste loss occurs with common cold or flu, it's usually associated with nasal congestion or rhinorrhea 4
• In contrast, COVID-19 related smell/taste loss often occurs without significant nasal congestion, making it a more distinctive symptom 1

Recovery Patterns

• For common cold and flu, smell and taste typically return as nasal congestion resolves 3
• In COVID-19, recovery of smell and taste function varies:
  • 44-73% of patients report improvement within the first month 5
  • Complete resolution occurs in 13-44% of cases, with partial resolution in others 1
  • Mean time to improvement is approximately 7.2 days, though recovery can take weeks or months 1

Mechanism of Smell/Taste Loss

• In common cold and flu, smell loss is primarily conductive (due to nasal obstruction blocking odor molecules) 4
• In COVID-19, evidence suggests both conductive and sensorineural mechanisms may be involved:
  • Obstructive mechanism affecting non-neuronal cells and supporting olfactory cells 1
  • Potential direct viral effects on taste and smell receptors 1

Diagnostic Approach

• Detailed history focusing on onset, duration, and associated symptoms is essential 6
• Objective taste/smell testing using standardized methods like the University of Pennsylvania Smell Identification Test (UPSIT) can help quantify impairment 6
• During pandemic periods, COVID-19 testing should be performed for sudden-onset taste/smell loss 6

Management Recommendations

• For common cold and flu-related smell/taste loss:
  • Symptomatic treatment of underlying nasal congestion may help 6
  • Hot drinks can provide subjective relief of nasal symptoms 4
• For persistent smell/taste loss (>3 months):
  • Olfactory training is recommended for at least 3-6 months 5
  • Safety precautions regarding food expiration and gas detection should be discussed 5

Key Differences Between COVID-19 and Other Viral Causes

• Higher prevalence of smell/taste loss in COVID-19 (59-98%) compared to other viral infections 1
• COVID-19 related smell/taste loss often occurs without significant nasal congestion 1
• Smell/taste loss can be the initial or only symptom in COVID-19 (11.8-26.6% of cases) 1
• Higher odds of olfactory/taste disturbance in COVID-19 compared to other respiratory viruses (OR=10.14) 1

Risk Factors for Persistent Smell/Taste Loss

• Female sex is associated with decreased odds of reporting recovery of smell (OR 0.74) and taste (OR 0.54) 7
• Younger age, female sex, e-cigarette use, and certain ethnicities may influence susceptibility to smell/taste loss 7