Features atypical of Bell’s palsy require referral for exclusion of an alternative diagnosis and include:
Insidious and painful onset. Gradual progression is more likely to be associated with a neoplastic or infectious cause of facial palsy.
A progressive and prolonged (more than 3 months) duration of symptoms with frequent relapses (indicative of a neoplastic process).
Predisposing factors for facial palsy, for example, previous stroke, brain tumour, parotid tumour, skin cancers of the head and face, or facial trauma.
Systemic illness or fever.
Vestibular or hearing abnormalities (other than hyperacusis), otorrhoea, diplopia or dysphagia.
Sparing of forehead movement (which may indicate an upper motor neurone lesion such as stroke) and bilateral signs (may be indicative of Lyme disease or sarcoidosis). Lower motor neurone lesions (such as Bell’s palsy) do not spare the upper face.
A recurrent episode.
Paralysis of individual branches of the facial nerve or other cranial nerve involvement.
Parotid gland masses, vesicular skin rashes, and lesions suggestive of skin cancer.