The most important species of coral snakes (Elapidae family) found in the United States are the eastern coral snake (Micrurus fulvius) and the Texas coral snake (Micrurus tener). Coral snakes have small mouths. Bites are usually limited to fingers, toes, or folds of skin. Due to a less efficient venom apparatus than the Crotalids, coral snakes generally need to hold on or chew to effect a significant envenomation. The bite typically produces minimal local inflammation and pain. Paresthesias and muscle fasciculations are common. Systemic symptoms resulting from the powerful neurotoxic effects of the venom can include tremors, drowsiness, euphoria, hypersalivation, and respiratory distress. Cranial nerve involvement, manifested by slurred speech and diplopia, may be followed by bulbar paralysis with dysphagia and dyspnea. Death may result from respiratory and cardiac arrest. Onset of severe symptoms may be delayed up to 12 hours but may also be rapidly progressive.
Management and Disposition
In contrast to pit viper envenomation, prehospital application of a constrictive bandage may be of benefit in limiting the spread of neurotoxic coral snake venom. Severe systemic symptoms following envenomation by Elapidae may be delayed and cannot be accurately predicted by local wound reactions. Four to six vials of antivenom should be administered for any suspected envenomation by eastern or Texas coral snakes. Treatment of western coral snake (Micruroides euryxanthus) bites is purely supportive. Tetanus prophylaxis should be addressed.
Coral Snake. United States eastern coral snake with typical coloring and red-on-yellow bands. (Photo contributor: Mike Cardwell, MS.)
Coral Snake (Close-Up). A close-up view of the striking and distinctive markings of the highly venomous coral snake. (Photo contributor: Mike Cardwell, MS.)
Nonvenomous Milk Snake. As opposed to the red-on-yellow rings seen in the venomous US coral snake, these red-on-black rings indicate a nonvenomous snake. Unfortunately, this applies only to animals native to the United States. (Photo contributor: Sean P. Bush, MD.)
Treatment with antivenom should be initiated early in cases of eastern coral snake bites, since symptoms are often delayed and severe.
The adage “red on yellow, kill a fellow; red on black, venom lack” applies to all coral snakes found in the United States but does not hold true in other parts of the world.
As many as 60% of North American coral snake bites do not result in envenomation of the victim.
Coral Snake Envenomation. Tooth mark from a coral snake bite. The snake latched onto this finger for 5 minutes. Ascending paresthesias after envenomation prompted intensive care unit admission and antivenom therapy. (Photo ...