Management of Hyperlacrimation (Crocodile Tears Syndrome) in Bell's Palsy
Botulinum toxin A injection into the lacrimal gland is the treatment of choice for crocodile tears syndrome in Bell's palsy patients with symptomatic gustatory hyperlacrimation. This intervention provides effective symptom relief for 3-6 months and can be repeated as needed when symptoms recur 1, 2, 3.
Understanding the Condition
Crocodile tears syndrome (gustatory hyperlacrimation) occurs as a sequela of Bell's palsy due to aberrant regeneration of facial nerve fibers. Instead of properly reinnervating salivary glands, parasympathetic fibers misdirect to the lacrimal gland, causing excessive tearing during eating or chewing 2, 4.
Key diagnostic features to confirm:
- Unilateral excessive tearing specifically triggered by eating, chewing, or salivary stimulation
- History of prior facial nerve palsy (Bell's palsy, trauma, or surgery)
- Schirmer test showing significantly increased lacrimation (>10mm increase) on affected side during gustatory stimulation 1, 5
- Patent lacrimal drainage system on scintigraphy (to exclude functional obstruction as the cause) 5
Treatment Algorithm
First-Line: Botulinum Toxin A Injection
Technique:
- Transconjunctival injection into the palpebral lobe of the lacrimal gland
- Initial dose: 2.5-6 units of botulinum toxin A 1, 3
- Can be administered in divided doses for safety
Expected outcomes:
- Symptom improvement within 2 weeks 5
- Duration of effect: 3-6 months 1, 2, 4
- Repeat injections when symptoms recur (typically after 4-6 months)
Evidence of efficacy: Studies demonstrate statistically significant reduction in Schirmer test values post-injection (from 27.8±3.58mm to 11.6±2.28mm, P=0.002) 1. Patients report near-complete resolution of symptoms with dramatic improvement in quality of life 2.
Important Caveats
Potential complications:
- Mild transient ptosis (most common, self-resolving) 1, 5
- Temporary reduction in baseline tear production
- No serious adverse events reported in multiple studies
When NOT to treat with botulinum toxin:
- If epiphora is due to functional lacrimal outflow obstruction rather than true hypersecretion 5
- Always confirm patent drainage system before proceeding with injection
Guideline Context
The American Academy of Otolaryngology-Head and Neck Surgery 2013 Bell's palsy guidelines [6-6] do not specifically address management of crocodile tears syndrome, as this is a late sequela rather than an acute complication. The guidelines emphasize referral to a facial nerve specialist for patients with ocular symptoms or incomplete recovery at 3 months 6, which would be the appropriate time to evaluate for synkinetic complications like crocodile tears.
Recent international guidelines 7, 8 conditionally recommend botulinum toxin injection for post-Bell's palsy synkinesis complications, supporting this approach for crocodile tears syndrome specifically.
Clinical Pearls
- Distinguish from simple epiphora: True crocodile tears syndrome has a clear gustatory trigger and increased tear production on Schirmer testing during stimulation
- Patient education is critical: Explain that this is a recognized complication of nerve regeneration, not a new disease process 9
- Consider early ophthalmology referral: Patients with incomplete facial recovery at 3 months should be evaluated for both motor and autonomic sequelae 6
- Repeat treatment is expected: This is not a failure but rather the natural course, as botulinum toxin effects are temporary by design