Sudden deafness: lack of evidence for systemic viral infection.

The cause of sudden deafness remains unknown even though available evidence suggests that viral infection could be one factor involved. The presence of an interferon-inducible protein termed MxA in patients' leukocytes is a good marker of a systemic viral infection. This study included 20 patients with sudden deafness and 12 control subjects. Peripheral blood leukocytes obtained from the patients with sudden deafness did not express significantly higher levels of interferon-alpha/beta-inducible MxA protein than control subjects. In addition, no measurable interferon-alpha activity was detected in any of the serum specimens. These findings suggest that sudden deafness is not commonly associated with a systemic viral infection.