Immunological concept for Bell's palsy: further experimental study.

This report concerns itself with additional experimental evidence to support the immunologic concept for the pathogenesis of Bell's palsy, using the mast cell as an index of immunological activity. In a previous experimental study, we postulated that degranulation of mast cells activated by complement or specific allergens with release of histamine and other substances may be the mechanism leading to nerve edema, ischemia, and paralysis. In this study we observed a loss of granulated mast cells in the more severely damaged facial nerves of immunized dogs after the intrafallopian canal injection of various substances, in contrast with the relative abundance of these cells in nerves that showed little or no evidence of injury. In addition, we demonstrated that cromolyn sodium, a mast cell degranulation inhibitor, when infused intravenously at the time of the intrafacial canal injection of horse serum, very effectively lessened the degree of experimental paralysis and histologic nerve injury.