Aetiology

Partial or complete paralysis of facial nerve (VII cranial nerve) due to damage to the facial nerve anywhere along its course.
This Clinical Management Guideline addresses Bell’s Palsy (idiopathic lower motor neurone facial nerve dysfunction), which constitutes approximately three quarters of all facial palsies:

• annual incidence 20-30 per 100,000, especially between 15 & 45 yrs with a possible second peak in the over-70s
• sudden onset, unilateral
• M = F (except in pregnancy, see below)
• cause unknown, but sometimes associated with latent virus infection (HSV type 1, Herpes zoster)
• fair prognosis without treatment: most people recover
  • however, up to 30% of treated patients do not recover completely
• better prognosis with systemic steroid therapy
• most improvement occurs within three weeks

Other causes of paralysis of the facial nerve, which are not addressed in this Clinical Management Guideline, include:

• infection, e.g. otitis media
• trauma, e.g. temporal bone fracture
• tumour compressing the facial nerve, e.g. acoustic neuroma
• sarcoidosis
• Guillain-Barré syndrome
• • Ramsay-Hunt syndrome (rare complication of Herpes Zoster infection)
• cerebrovascular accident (stroke), in which forehead muscle function is preserved (upper motor neurone lesion)

Predisposing factors

Bell’s Palsy is more common in:

• pregnancy (annual incidence increases to 45 per 100,000)
• diabetes
• HIV

Although there have been case reports of isolated facial paralysis after viral vaccination (including mRNA COVID-19 vaccines), more detailed pharmacoepidemiological studies have not found an association.

Symptoms of facial palsy (Bell’s palsy)

Distressing cosmetic change due to loss of muscle tone on one side of face. May report changes in taste and salivation.

Ocular exposure causes:

• redness, discomfort, pain, photophobia, reduced vision

Signs of facial palsy (Bell’s palsy)

Lid and periocular:

• unilateral facial weakness including orbicularis oculi leading to:
  • eyebrow droop and inability to raise it
  • incomplete blink leads to corneal drying
  • incomplete closure at night (lagophthalmos) (causes prolonged corneal exposure and dry eye)
  • ectropian
  • loss of lacrimal pump mechanism (produces tear pooling and epiphora)

Conjunctiva:

• hyperaemia
• oedema
• staining

Cornea: 

• desiccation signs range from mild superficial punctate erosions to frank ulceration (usually inferior).
• reduced corneal sensation

Differential diagnosis

A detailed history is important to rule out other causes of facial nerve palsy (see aetiology section). Bells Palsy is a diagnosis of exclusion.

Ectropion or Entropion (see appropriate Clinical Management Guidelines)
Other causes of lagophthalmos

• orbital (thyroid eye disease – assess by exophthalmometry)
• mechanical (cicatricial – look for lid scarring)
• physiological (patient’s carer, or partner to check for full lid closure at night if possible)

Management by optometrist

Practitioners should work within their scope of practice, and where necessary seek further advice or refer the patient elsewhere

GRADE* Level of evidence and strength of recommendation always relates to the statement(s) immediately above

Tape lids closed at night (and during day if corneal desiccation is marked)
(GRADE*: Level of evidence=low, Strength of recommendation=strong)

Sunglasses for photophobia and general protection
(GRADE*: Level of evidence=low, Strength of recommendation=strong)

Therapeutic contact lens (if unresponsive to frequent use of ocular lubricants during the acute phase or to manage complications)

• silicone hydrogel should be considered as first choice (however, scleral lens gives maximum protection)

NB therapeutic contact lens fitting is contraindicated in cases of neurotrophic keratitis with loss of corneal sensation (cranial nerve V). Such patents are at high risk of infection, which may be further increased by contact lens wear
(GRADE*: Level of evidence=low, Strength of recommendation=weak)

See CMG on Dry Eye

Tear supplements / lubricants by day, unmedicated ointment at night
(GRADE*: Level of evidence=low, Strength of recommendation=strong)

Management category

New cases, and where there is loss of corneal sensation:

A2: first aid measures and emergency (same day) referral to GP or hospital A&E department

Improved prognosis in moderate/severe cases of Bell’s palsy if treated early with systemic corticosteroid i.e. within 72 hours of onset.

Combination therapy with anti-virals e.g. acyclovir or valaciclovir, provides no additional benefit to rates of complete recovery but probably reduces rates of late sequelae compared to corticosteroids alone.
NB: corneal ulceration due to exposure is potentially sight threatening and may justify emergency referral

Recovering and established cases:
B2: alleviation/palliation; no referral

If cannot be managed easily, then:
B1: prescription of drugs; routine referral

Possible management in secondary care or local primary/community pathways where available

Additional guidance may be available

Urgent medical treatment for new cases:

• systemic steroid ± anti-viral

Temporary tarsorrhaphy

Upper lid lowering with botulinum toxin injection of levator muscle

Eyelid surgery for permanently unrecovered cases:

• tarsorrhaphy (permanent)
• upper lid lowering (surgery, gold or platinum weight)
• surgical sling to raise lower lid
• there is insufficient evidence on the value of surgical decompression of the
  facial nerve

Evidence base

*GRADE: Grading of Recommendations Assessment, Development and Evaluation (www.gradeworkinggroup.org)
 

Sources of evidence

Baugh R, Basura G, Ishii L, et al. Clinical practice guideline: Bell’s palsy. Otolaryngol Head Neck Surg. 2013;149(3)(suppl):S1-S27

de Almeida JR, Guyatt GH, Sud S, Dorion J, Hill MD, Kolber MR, Lea J, Reg SL, Somogyi BK, Westerberg BD, White C, Chen JM; Bell Palsy Working Group, Canadian Society of Otolaryngology. Management of Bell Palsy: clinical practice guideline. Head and Neck Surgery and Canadian Neurological Sciences Federation. CMAJ. 2014;186(12):917- 22

Gagyor I, Madhok VB, Daly F, Sullivan F. Antiviral treatment for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2019;9:CD001869

Madhok VB, Gagyor I, Daly F, Somasundara D, Sullivan M, Gammie F, Sullivan F. Corticosteroids for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2016;7:CD001942

Menchetti I, McAllister K, Walker D, Donnan PT. Surgical interventions for the early management of Bell's palsy. Cochrane Database Syst Rev. 2021;1(1):CD007468.

Moncaliano MC, Ding P, Goshe JM, Genther DJ, Ciolek PJ, Byrne PJ. Clinical features, evaluation, and management of ophthalmic complications of facial paralysis: A review. J Plast Reconstr Aesthet Surg. 2023;87:361-368. 

Renoud L, Khouri C, Revol B, Lepelley M, Perez J, Roustit M, Cracowski JL. Association of facial paralysis with mRNA COVID-19 vaccines: a disproportionality analysis using the World Health Organization Pharmacovigilance Database. JAMA Intern Med. 2021;181(9):1243-1245.

Facial Palsy (Bell’s Palsy)
Version 15
Date of search 16.04.24
Date of revision 30.05.24
Date of publication 02.07.24
Date for review 15.04.26
© College of Optometrists