Bell's palsy during interferon therapy for chronic hepatitis C infection in patients with haemorrhagic disorders.

Two adult patients with life-long severe haemorrhagic disorders commenced on interferon-alpha2b therapy for chronic hepatitis C infection. Both developed Bell's palsy several weeks after commencing therapy, They were started on steroids and, in addition, the first patient discontinued interferon-alpha2b therapy while the second patient elected to continue with therapy. In both cases facial paralysis improved over the ensuing weeks. Bell's palsy is often idiopathic but has been reported. in association with herpesviruses. It is not a recognised complication of chronic hepatitis B or C infection, or interferon-alpha2b therapy. However, the interferons are associated with numerous adverse reactions including various neuropsychiatric manifestations and neurological syndromes. There are several reports of nerve palsies, including optic tract neuropathy, occurring during interferon therapy, and immune-based mechanisms are thought to play a role in the aetiopathogenesis. No reports of Bell's palsy in association with interferon therapy were identified in our literature search, although one possible case has been reported to the Committee of Safety in Medicine. Although Bell's palsy in our patients may have occurred by chance, a neuropathic effect of interferon-alpha2b on the facial nerve cannot be excluded and we urge physicians using interferons to be aware of this potential side-effect.