Bell’s Palsy: Acute Peripheral Facial Paralysis in Clinical Practice

By: Nesredin Hassen Yesuf

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Introduction

Bell’s palsy is the most common cause of acute unilateral lower motor neuron facial paralysis and remains a frequent presentation in primary care, emergency medicine, and neurology. Characterized by sudden onset of facial weakness without an identifiable structural cause, it accounts for the majority of cases of peripheral facial nerve palsy. Although often self-limiting, early recognition and treatment significantly improve outcomes and reduce long-term complications [1].

Clinical Presentation

Bell’s palsy typically presents with rapid onset unilateral facial weakness developing over hours to 72 hours. Patients may notice facial drooping, inability to close the eye, difficulty smiling, drooling, and impaired forehead movement. Unlike central causes of facial weakness such as stroke, Bell’s palsy affects both the upper and lower facial muscles due to peripheral seventh cranial nerve involvement.

Additional symptoms may include altered taste on the anterior two-thirds of the tongue, hyperacusis, reduced lacrimation, and mild retroauricular pain. The abrupt progression and absence of other focal neurological deficits help support the diagnosis.

Pathophysiology

Although termed idiopathic, Bell’s palsy is widely believed to result from viral-mediated inflammation of the facial nerve. Reactivation of latent herpes simplex virus type 1 is strongly implicated. Inflammation leads to edema within the narrow facial canal, causing compression and impaired nerve conduction [4]. This mechanism explains both the sudden onset and the typically reversible nature of the condition.

Diagnosis

Bell’s palsy is primarily a clinical diagnosis. A careful neurological examination is essential to distinguish peripheral from central facial weakness. Forehead involvement is a key differentiating feature, as upper facial muscles are spared in most central lesions due to bilateral cortical innervation.

Further investigation is unnecessary in typical cases. However, atypical features such as gradual onset, bilateral involvement, recurrent episodes, or additional neurological signs warrant further evaluation to exclude alternative causes [1].

Management

Corticosteroids are the cornerstone of treatment. Early administration—ideally within 72 hours of symptom onset—significantly increases the likelihood of complete recovery [2]. Prednisolone is the most commonly used agent.

The addition of antiviral therapy remains debated. While antivirals alone have limited benefit, combination therapy may offer modest additional improvement in certain cases [2]. Current clinical guidelines support corticosteroids as first-line treatment, with antivirals considered in selected patients [1].

Eye protection is a critical component of management. Incomplete eyelid closure can lead to corneal dryness, ulceration, and vision-threatening complications. Artificial tears, lubricating ointments, and protective measures should be implemented when necessary.

Prognosis

The prognosis of Bell’s palsy is generally favorable. Approximately 70–85% of patients achieve complete recovery, often within weeks to months [3]. Poor prognostic factors include complete paralysis at onset, older age, and delayed treatment.

A minority of patients may develop residual weakness or synkinesis, characterized by involuntary facial movements during voluntary actions. Early therapy and appropriate follow-up reduce the risk of long-term sequelae.

Conclusion

Bell’s palsy is an acute peripheral facial neuropathy with a typically benign course but significant short-term functional and psychological impact. Prompt recognition, exclusion of alternative diagnoses, and early corticosteroid therapy are essential for optimizing recovery. Despite its common occurrence, the condition remains an important reminder of the clinical value of thorough neurological examination and timely intervention.

References

1. Baugh RF, Basura GJ, Ishii LE, Schwartz SR, Drumheller CM, Burkholder R, et al. Clinical practice guideline: Bell’s palsy. Otolaryngol Head Neck Surg. 2013;149(3 Suppl):S1–27.

2. Sullivan FM, Swan IR, Donnan PT, Morrison JM, Smith BH, McKinstry B, et al. Early treatment with prednisolone or acyclovir in Bell’s palsy. N Engl J Med. 2007;357(16):1598–607.

3. Peitersen E. Bell’s palsy: the spontaneous course of 2500 peripheral facial nerve palsies of different etiologies. Acta Otolaryngol Suppl. 2002;(549):4–30.

4. Gilden DH. Clinical practice. Bell’s palsy. N Engl J Med. 2004;351(13):1323–31.

Assessed and Endorsed by the MedReport Medical Review Board