Methemoglobinemia: an unusual complication of topical anesthesia.

Allergic reactions tend to be easily recognized and treated, but methemoglobinemia is a rare, life-threatening complication of topical anesthesia of which our staff was unaware until recently. Team work prevented a patient fatality. Directives to alert the staff to suspect methemoglobinemia in patients who develop cyanosis and decreased oxygen saturation levels after administration of topical anesthesia despite administration of oxygen will prevent fatalities in the future.