What is the protocol for a systemic corticosteroid (corticosteroid) trial for olfactory dysfunction?

Systemic Corticosteroid Trial for Olfactory Dysfunction

A systemic corticosteroid trial for olfactory dysfunction typically involves oral prednisolone 25-60 mg daily for 7-21 days, which can significantly improve olfactory function, particularly in patients with sinonasal causes of smell loss. 1

Protocol Details

Medication and Dosing

• Medication choice: Prednisolone or prednisone is most commonly used
• Dosage range:
  • 25-60 mg daily for adults 1
  • Typically administered as a single morning dose before 9 am 2
• Duration: 7-21 days 1
  • Most studies use 14-day courses 3
  • Some protocols use a tapering schedule (e.g., methylprednisolone 32mg/day for days 1-5, 16mg/day for days 6-10, 8mg/day for days 11-20) 1

Patient Selection

• Most effective for patients with:
  • Chronic rhinosinusitis with nasal polyps (CRSwNP) 1
  • Sinonasal causes of olfactory dysfunction 3, 4
  • Particularly effective in patients with sinonasal disease with nasal polyps 3
• Less effective for:
  • Post-traumatic olfactory loss
  • Idiopathic olfactory dysfunction 4

Assessment Protocol

1. Pre-treatment evaluation:

   • Baseline olfactory function testing using standardized tests (e.g., "Sniffin' Sticks" test battery or similar) 3
   • Document threshold, discrimination, and identification scores

2. Post-treatment evaluation:

   • Repeat olfactory function testing 2-4 weeks after starting treatment 1
   • Success is typically defined as improvement of more than 6 points on the TDI (Threshold, Discrimination, Identification) score 5

Follow-up Management

• If improvement occurs but is not maintained:
  • Consider transitioning to topical corticosteroids 5
  • Topical corticosteroids applied with a squirt system directly to the olfactory cleft are more effective than standard nasal sprays 6, 5
• For partial responders:
  • Consider intermittent short courses of systemic corticosteroids (1-2 courses per year) 1
  • Maintenance with topical corticosteroids between systemic courses 5

Efficacy and Expectations

• Approximately 26.6% of all patients show significant improvement (>6 points on TDI score) 3
• Higher success rate (36.7%) in patients with sinonasal olfactory dysfunction 3
• Effects are often seen within days, particularly for olfaction, even before visible changes in polyp volume 1
• Response is typically better in patients with lower baseline olfactory function 3

Safety Considerations

• Short-term adverse effects include:

  • Insomnia (26% vs 10% with placebo)
  • Nervousness (18% vs 8%)
  • Increased appetite (22% vs 10%)
  • Mood changes
  • Glucose intolerance
  • Dyspepsia 7, 2

• For courses less than 1 week, gradual dose reduction is not necessary 7

• For courses up to 10 days, gradual reduction is probably not necessary, especially if patients are taking inhaled corticosteroids simultaneously 7

• Take medication with food or milk to reduce gastric irritation 2

Important Caveats

• Systemic corticosteroids provide temporary improvement in many cases, with effects diminishing over time 1
• The EPOS2020 guideline suggests limiting systemic corticosteroid use to 1-2 courses per year for patients with partially or uncontrolled disease 1
• Patients should be counseled that at best, treatment is effective in about half of patients with sinonasal disease 3
• Topical corticosteroid sprays alone (without prior systemic treatment) have not shown significant improvement for non-CRS related olfactory dysfunction 4