Introduction
Bell’s palsy, an acute, idiopathic unilateral lower motor neuron facial weakness, is a common presentation in primary and secondary care. In the UK, clinicians primarily refer to two national evidence-based guidelines: the National Institute for Health and Care Excellence (NICE) Clinical Knowledge Summary (CKS) on Bell’s palsy (last revised October 2023, reviewed for this 2025 comparison) and the Scottish Intercollegiate Guidelines Network (SIGN) guideline 144, “Management of Bell’s Palsy” (published December 2013). While both aim to standardise care, their recommendations differ in key areas, reflecting their publication dates and methodological approaches. This comparison provides a factual analysis for UK clinicians, highlighting these differences and their practical implications for diagnosis, treatment, and management.
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Diagnosis and Assessment
NICE CKS
- Focus: Pragmatic primary care assessment to exclude red flags and establish a diagnosis.
- History & Examination: Emphasises a focused history (onset, associated symptoms) and examination of all facial nerve branches (frontal, orbital, buccal, mandibular) to confirm a lower motor neuron lesion and assess severity.
- Red Flags: Strong emphasis on identifying features suggestive of an alternative diagnosis (e.g., stepwise progression, bilateral weakness, limb weakness, vesicular rash, new headache, history of cancer) which warrant urgent referral.
- Investigations: Does not routinely recommend blood tests, lumbar puncture, or imaging for typical cases. Imaging (MRI) is reserved for atypical presentations or when red flags are present.
SIGN 144
- Focus: A more detailed diagnostic workup, including severity assessment.
- Severity Scoring: Recommends the use of a formal grading scale, specifically the House-Brackmann scale, at initial assessment and for monitoring progress.
- Investigations: Suggests that electroneuronography (ENoG) may be considered by specialists to provide prognostic information in cases of complete paralysis.
- Lyme Disease: More explicitly discusses testing for Lyme disease in endemic areas or with relevant exposure history.
Key Differences & Practical Takeaway
The core difference lies in formal severity scoring. SIGN’s recommendation to use the House-Brackmann scale provides an objective baseline for monitoring, which can be valuable in communication with specialists. NICE takes a more pragmatic, primary-care-focused approach, prioritising the exclusion of sinister pathology over formal grading. In practice, documenting severity descriptively (e.g., "incomplete eye closure") is essential regardless of the guideline followed.
Treatment
Pharmacological Management
NICE CKS
- Corticosteroids: Strongly recommends offering oral prednisolone (25 mg twice daily for 10 days) to all patients aged 16 and over, within 72 hours of symptom onset. This is based on high-quality evidence showing improved recovery rates.
- Antivirals: Advises against the routine use of antiviral monotherapy. States that the evidence for combining antivirals with steroids is uncertain and does not recommend it routinely.
SIGN 144
- Corticosteroids: Recommends oral prednisolone (50 mg daily for 10 days) for patients aged 16 and over, started within 72 hours of onset.
- Antivirals: Recommends that antiviral therapy should be considered in combination with steroids for patients with severe to complete paralysis. This was based on a different interpretation of the evidence available in 2013.
Non-Pharmacological Management
Both guidelines agree on core supportive measures:
- Eye Care: Paramount importance is given to protecting the cornea. Recommendations include liberal use of lubricating eye drops during the day and ointment at night, taping the eye closed during sleep, and urgent ophthalmology referral if exposure keratopathy is suspected.
- Physiotherapy/Facial Exercises: Both are cautious. NICE states there is insufficient evidence to recommend routine facial exercises or massage. SIGN suggests that facial retraining therapy may be beneficial for patients with synkinesis or limited recovery, but not in the acute phase.
Key Differences & Practical Takeaway
The most significant divergence is the use of antiviral agents. NICE, reflecting more recent meta-analyses, advises against their routine use. SIGN, being older, permits their consideration in severe cases. The steroid dosing regimen also differs (50mg once daily vs. 25mg twice daily), though the total daily dose is similar. The practical takeaway for UK clinicians in 2025 is to follow the NICE recommendation: offer steroids within 72 hours to all eligible patients, but do not routinely prescribe antivirals. This aligns with the most current evidence and is the standard expected in most English and Welsh practices.
Special Situations and Referral
NICE CKS
- Pregnancy: Advises that corticosteroids can be considered after discussion of the potential risks and benefits with the patient and an appropriate specialist (e.g., obstetrician).
- Children: Notes that the evidence for steroids in children is limited. Recommends referral to a paediatric specialist for management decisions.
- Referral: Urgent referral (same day/within 24 hours) is advised for red flag symptoms, severe pain, or incomplete eye closure requiring management. Referral to a specialist (e.g., ENT/Neurology) is recommended if there is no improvement after 3 weeks or if symptoms worsen.
SIGN 144
- Pregnancy & Children: Does not provide specific detailed recommendations for these groups, reflecting the evidence base at the time of publication.
- Referral: Emphasises referral to a specialist multidisciplinary team for cases with poor prognostic factors (e.g., complete paralysis, no recovery after 6 months) for consideration of interventions like botulinum toxin for synkinesis or surgical options.
Key Differences & Practical Takeaway
NICE provides more contemporary and specific guidance on managing Bell’s palsy in pregnancy and children, which is a crucial gap in the older SIGN guideline. Both agree on the principles of urgent referral for red flags, but SIGN places more emphasis on long-term management and referral for rehabilitation in cases of incomplete recovery.
Practical Clinical Flow for UK Clinicians (2025)
- Presentation: Patient presents with acute unilateral facial weakness.
- Assessment: Take history; examine all facial nerve branches. Actively exclude red flags (bilateral weakness, rash, neurological signs).
- Diagnosis: If typical Bell’s palsy is diagnosed and onset was <72 hours ago, proceed to treatment.
- Treatment: Offer prednisolone 25mg twice daily for 10 days (NICE regimen) to patients ≥16 years without contraindications. Do not routinely prescribe antivirals.
- Supportive Care: Instigate intensive eye care advice (drops/ointment/taping). Provide patient information and reassurance.
- Safety Netting: Advise to return if symptoms worsen, no improvement after 3 weeks, or if eye pain/redness develops.
- Referral: Refer urgently if red flags appear. Refer to ENT/Neurology if no improvement after 3 weeks or for severe, persistent symptoms.
Frequently Asked Questions (FAQs) for Clinicians
1. Which guideline should I follow in Scotland/Northern Ireland?
While SIGN is Scottish, its age means that many Scottish health boards may align with the more recent NICE CKS, particularly regarding antivirals. Local NHS board policies should be checked. In Northern Ireland, NICE guidance is generally adopted. The most evidence-based approach in 2025 is to follow the NICE recommendations on treatment.
2. A patient presents at 80 hours (just over 72 hours). Should I still offer steroids?
The 72-hour window is based on optimal evidence. However, clinical judgement is key. NICE suggests that for presentations up to 1 week after onset, corticosteroids may still be considered, acknowledging that the benefit is likely to be reduced. Discuss the uncertainty of benefit with the patient.
3. How should I manage a pregnant patient?
Follow NICE advice: Corticosteroids are not contraindicated but require a careful risk-benefit discussion. Involve an obstetrician early in the decision-making process, especially if considering treatment.
4. What is the role of imaging in a typical case?
Neither guideline recommends imaging for typical Bell’s palsy. MRI is indicated only if the diagnosis is uncertain, red flags are present (suggesting a central lesion or mass), or there is no recovery after several months.
5. How should I manage a patient with no recovery after 6 months?
This aligns with SIGN’s emphasis on long-term care. Refer to a specialist multidisciplinary facial palsy clinic (often ENT or Maxillofacial led) for assessment. Management may include botulinum toxin for synkinesis, facial retraining therapy, or discussion of surgical options (e.g., nerve grafts, muscle transfers).
Source Links
- NICE Clinical Knowledge Summary (CKS) - Bell's Palsy: NICE CKS: Bell's palsy (Last revised October 2023).
- SIGN 144 - Management of Bell’s Palsy: SIGN 144 (PDF) (Published December 2013).