A woman with acute left peripheral facial nerve palsy, mastoid pain, normal otoscopic exam, and no sensory loss—what is the most appropriate acute treatment: acyclovir, doxycycline, observation, prednisone, or valacyclovir?

Acute Treatment of Bell's Palsy

Prednisone is the most appropriate acute treatment for this patient with Bell's palsy, and it must be initiated immediately within 72 hours of symptom onset. 1

Clinical Diagnosis

This patient presents with classic Bell's palsy:

• Acute unilateral peripheral facial nerve palsy involving the forehead (inability to wrinkle left forehead), indicating a lower motor neuron lesion 1, 2
• Rapid onset (since awakening this morning, consistent with <72 hour timeframe) 1, 2
• Mastoid pain is a common associated symptom of Bell's palsy 2
• Normal otoscopic exam excludes middle ear pathology 1
• No sensory loss and no other cranial nerve involvement excludes stroke and other central causes 2

The forehead involvement is the critical distinguishing feature—stroke spares the forehead due to bilateral cortical innervation of upper facial muscles, whereas Bell's palsy affects all ipsilateral facial muscles 2.

Treatment Algorithm

First-Line: Oral Corticosteroids (REQUIRED)

Initiate immediately with one of these regimens:

• Prednisone 60 mg once daily for 5 days, followed by a 5-day taper (reduce by 10 mg every day), OR 1
• Prednisolone 50 mg once daily for 10 days (no taper required) 1

Evidence supporting steroids:

• 83% complete recovery at 3 months with prednisolone versus 63.6% with placebo (NNT = 6) 1
• 94.4% complete recovery at 9 months with prednisolone versus 81.6% with placebo (NNT = 8) 1
• Treatment must begin within 72 hours; no benefit exists beyond this window 1

Optional Add-On: Antiviral Therapy

Combination therapy may be offered (steroids + antiviral) within 72 hours for a modest additional benefit:

• Valacyclovir 1 g three times daily for 7 days, OR 1, 3
• Acyclovir 400 mg five times daily for 10 days 1, 3

Evidence for combination therapy:

• 96.5% complete recovery with steroids + antiviral versus 89.7% with steroids alone (absolute benefit +6.8%) 1
• This represents a small incremental gain; the American Academy of Otolaryngology classifies this as an "option" rather than a strong recommendation 1

Critical: Antiviral monotherapy is NEVER appropriate—acyclovir or valacyclovir alone provides no benefit and delays effective steroid treatment 1, 3

Why Other Options Are Incorrect

• Acyclovir alone: Ineffective as monotherapy; must be combined with steroids if used at all 1, 3
• Doxycycline: No role in Bell's palsy unless Lyme disease is suspected (not indicated here with normal exam and no endemic exposure history) 2
• Expectant observation: Inappropriate—30% of untreated patients have incomplete recovery with permanent sequelae, versus 6-17% with steroid treatment 1, 4
• Valacyclovir alone: Same as acyclovir—ineffective as monotherapy 1

Mandatory Eye Protection (Immediate Implementation)

All patients with incomplete eye closure require aggressive corneal protection:

• Lubricating ophthalmic drops every 1-2 hours while awake 1
• Ophthalmic ointment at bedtime for sustained moisture 1
• Eye taping or patching at night with proper technique instruction to avoid corneal abrasion 1
• Sunglasses outdoors to shield from wind and debris 1

Failure to protect the eye can result in permanent corneal damage including exposure keratitis 1.

Follow-Up Requirements

Mandatory reassessment or specialist referral if:

• Incomplete facial recovery at 3 months after symptom onset 1
• New or worsening neurologic findings at any point (suggests alternative diagnosis) 1
• Development of ocular symptoms at any time (requires urgent ophthalmology referral) 1

Common Pitfalls to Avoid

• Delaying treatment beyond 72 hours eliminates the proven benefit of corticosteroids 1
• Using antiviral monotherapy is ineffective and delays appropriate steroid treatment 1, 3
• Inadequate eye protection can lead to permanent corneal damage in patients with lagophthalmos 1
• Ordering routine laboratory tests or imaging delays treatment without improving outcomes in typical presentations 1
• Failing to distinguish from stroke—always verify forehead involvement (present in Bell's palsy, absent in stroke) and absence of other neurologic deficits 2