What is the appropriate diagnostic workup and treatment for anosmia in a 70-year-old patient?

Anosmia in a 70-Year-Old: Diagnosis and Treatment

In a 70-year-old patient with anosmia, perform validated psychophysical smell testing (UPSIT or Sniffin' Sticks) as the primary diagnostic tool, obtain a focused history to identify red flags and etiology, and initiate treatment with intranasal corticosteroids combined with olfactory training, which have the strongest evidence for efficacy.

Diagnostic Workup

Initial Assessment

The diagnostic evaluation centers on validated orthonasal smell tests as the cornerstone of diagnosis 1. Self-assessment of olfactory function is notoriously unreliable, particularly in elderly patients where gradual decline often goes undetected 2. The two most validated tests are:

• University of Pennsylvania Smell Identification Test (UPSIT) - 40-item standardized test
• Sniffin' Sticks - European validated alternative

These tests objectively quantify the degree of dysfunction (anosmia vs. hyposmia) and establish baseline function for monitoring treatment response 1.

Critical History Elements

Focus your history on:

• Onset and duration: Sudden vs. gradual (viral vs. neurodegenerative)
• Associated symptoms: Nasal obstruction, rhinorrhea, postnasal drip (suggests inflammatory/CRS etiology)
• Red flags requiring urgent evaluation:
  • Unilateral symptoms
  • Facial pain
  • Serosanguinous nasal discharge
  • Visual changes
  • Progressive neurological symptoms
• Recent viral illness: Including COVID-19 exposure 3
• Trauma history: Head injury
• Medication review: Many drugs cause dysgeusia/hyposmia 2
• Neurodegenerative symptoms: Memory loss, tremor, gait changes (Parkinson's/Alzheimer's screening) 2

Age-Specific Considerations

In patients over 70, anosmia prevalence is markedly elevated due to multiple factors: reduced olfactory epithelial regeneration, decreased mucus secretion, hormonal changes, and epithelial thinning 2. Olfactory dysfunction in this age group strongly correlates with neurodegenerative disease, particularly Alzheimer's disease (where severity correlates with disease progression) and Parkinson's disease (where olfactory loss precedes motor symptoms by years) 2.

Imaging

Imaging is NOT routinely indicated for primary diagnosis of anosmia 1. Reserve MRI for:

• Presence of red flag symptoms (unilateral disease, visual changes, serosanguinous discharge)
• Suspected structural lesions or neoplasm
• Unexplained anosmia after initial workup
• Consideration of neurodegenerative disease workup

CT imaging may be appropriate if chronic rhinosinusitis is suspected based on history and examination.

Treatment Approach

First-Line Therapy (Strongest Evidence)

Initiate combination therapy with:

1. Intranasal corticosteroids - Most robust evidence for efficacy in post-infectious and inflammatory anosmia 4, 5

   • Continue for minimum 3 months before assessing response
   • Particularly effective in CRS-related smell loss

2. Olfactory training - Level 1 evidence supporting efficacy 4

   • Systematic exposure to 4 distinct odors (rose, eucalyptus, lemon, clove) twice daily
   • Duration: minimum 3-6 months
   • Mechanism: promotes neuroregeneration of olfactory receptor neurons
   • Refer patient to www.fifthsense.org.uk for validated protocols 3

Etiology-Specific Considerations

Post-viral anosmia (including COVID-19):

• Natural recovery occurs in 13-73% of cases, typically within 7 days to several weeks 3
• Intranasal corticosteroids plus olfactory training remain first-line
• Prognosis generally favorable but may take months 3

Inflammatory/CRS-related:

• Intranasal corticosteroids are particularly effective 5
• Consider nasal saline irrigation as adjunct
• Second-line: systemic corticosteroids (short course)
• Emerging biologics (dupilumab, omalizumab, mepolizumab) show promise for type 2 inflammation in CRSwNP 5

Age-related/neurodegenerative:

• No adequate treatment exists to reverse age-related decline 2
• Olfactory training may provide modest benefit
• Focus on safety counseling (see below)
• Consider neurology referral if concurrent cognitive/motor symptoms

Second-Line Options

• Systemic corticosteroids: Short courses for inflammatory causes (weigh risks in elderly)
• Surgical intervention: Reserved for structural/CRS cases refractory to medical management
• Zinc supplementation: Mixed evidence, may consider if deficiency suspected 6

Critical Safety Counseling

Patients with anosmia face significant safety risks and quality of life impairment 7, 8:

• Install smoke/gas detectors in home (cannot detect fire/gas leak)
• Check food expiration dates meticulously (cannot detect spoiled food)
• Use caution with personal hygiene (cannot detect body odor)
• Avoid relying on smell for cooking (risk of burning food/fire)

Monitoring and Follow-Up

• Repeat validated smell testing at 3-6 months to assess treatment response
• Continue successful therapies long-term
• Persistent anosmia despite 6 months of treatment warrants specialist ENT referral
• Consider neurology evaluation if age >70 with unexplained anosmia (neurodegenerative screening)

Key Pitfalls to Avoid

• Do not rely on patient self-assessment - requires objective testing 2
• Do not order routine imaging without red flags 1
• Do not dismiss as "normal aging" without excluding treatable causes and neurodegenerative disease 2
• Do not forget safety counseling - has profound impact on morbidity and quality of life 7, 8