What is the workup for a patient presenting with loss of taste sensation?

Workup for Loss of Taste Sensation

The workup for loss of taste sensation should begin with a detailed assessment of temporal relationship to viral illness (particularly COVID-19), followed by standardized taste/smell testing, and imaging studies only when neurological symptoms are present or symptoms persist beyond 6 months despite therapy. 1

Initial Assessment

• Obtain a detailed history focusing on:

  • Onset and duration of symptoms 2, 1
  • Temporal relationship with viral infections, particularly COVID-19 2
  • Associated symptoms (nasal congestion, rhinorrhea, neurological symptoms) 2, 3
  • Medication use that may affect taste 4
  • History of head trauma 5
  • Smoking and alcohol consumption 6

• Physical examination should include:

  • Complete examination of cranial nerves 5
  • Thorough examination of oral cavity for signs of candidiasis or poor oral hygiene 4
  • Nasal examination for signs of obstruction or inflammation 2

Diagnostic Testing

• Objective taste testing using standardized methods:

  • University of Pennsylvania Smell Identification Test (UPSIT) for olfactory function 2, 1
  • Spatial taste tests using filter paper soaked in taste solutions for specific tongue areas 7
  • Taste sticks or tasting tablets for gustatory testing 3

• Laboratory studies:

  • Complete blood count with differential 4
  • Serum iron, zinc, and copper levels (iron deficiency is associated with hypogeusia) 4
  • COVID-19 testing if recent onset or during pandemic 2

• Imaging studies (only when indicated):

  • MRI with olfactory protocol is recommended when:
    • Symptoms persist beyond 6 months despite therapy 1
    • Neurological symptoms are present 2, 1
    • No clear temporal relationship to viral infection exists 1
  • CT of paranasal sinuses when sinonasal inflammatory disease is suspected 2

Special Considerations for COVID-19

• Loss of taste and smell is a significant presenting symptom of COVID-19 infection 2
• COVID-19 testing should be performed in patients with sudden onset taste/smell loss, especially during pandemic periods 2
• Recovery from COVID-related taste loss typically occurs within weeks, with 44-73% reporting improvement within the first month 2
• Patients with persistent symptoms beyond 3 months should be evaluated for long-term management 1

Treatment Approach

• Olfactory training is the primary recommended treatment for persistent taste/smell loss:

  • Should be started immediately and continued for at least 3-6 months 1
  • Protocol involves sniffing four different strong-smelling substances for 20 seconds each, twice daily 1

• Address underlying causes:

  • Iron supplementation if deficiency is detected 4
  • Antifungal treatment if oral candidiasis is present 4
  • Discontinuation of offending medications 4
  • Treatment of sinonasal inflammatory disease if present 2

• Safety precautions:

  • Install gas alarms and smoke detectors 1
  • Be vigilant about food expiration dates 1
  • Connect patients with support resources 1

Follow-up Recommendations

• Re-evaluate patients at 1 month, 3 months, and 6 months after initiating treatment 1
• Consider referral to an otolaryngologist or specialized smell and taste clinic if no improvement after 3-6 months 1
• Consider neuroimaging if symptoms persist beyond 6 months despite therapy 1

Common Pitfalls

• Failing to distinguish between true gustatory loss (bitter, sweet, salty, sour, umami) and olfactory loss affecting flavor perception 3
• Overlooking COVID-19 as a potential cause, especially when taste/smell loss is the primary symptom 2
• Ordering unnecessary neuroimaging when there is a clear temporal relationship to viral infection 1
• Not addressing potential safety concerns related to inability to detect spoiled food or gas leaks 1