DIAGNOSIS
The diagnosis of Bell palsy must be made on the basis of a thorough history and physical examination, as well as the use of diagnostic testing when necessary. Bell palsy is a diagnosis of exclusion. Clinical features of the disorder that may help to distinguish it from other causes of facial paralysis include the sudden onset of unilateral facial paralysis and the absence of signs and symptoms of CNS, ear, and cerebellopontine angle disease.
Bell's palsy is an acute peripheral facial weakness of unknown cause and the diagnosis can be established without difficulty in patients with unexplained unilateral isolated facial weakness. The onset is sudden and symptoms typically peak within a few days. Additional symptoms may include pain in or behind the ear, numbness or tingling in the affected side of the face usually without any objective deficit on neurological examination, hyperacusis and disturbed taste on the ipsilateral anterior part of the tongue.[1] Bilateral idiopathic facial palsy occurs less frequently than unilateral involvement. About 7% of patients with history of Bell's palsy may experience recurrence. The mean interval to first recurrence is reported at 9.8 years after the first episode.