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Scorpion stings in the United States and Mexico

Frank LoVecchio, DO, MPH, FACEP
Section Editors
Daniel F Danzl, MD
Stephen J Traub, MD
Michele M Burns, MD, MPH
Deputy Editor
James F Wiley, II, MD, MPH


Scorpion envenomation is a significant problem in the southwestern United States and throughout Mexico. In the United States, Centruroides exilicauda (sculpturatus) stings are associated with major neurologic toxicity, especially in young children. In Mexico, multiple toxic species exist, and annual mortality due to scorpion envenomation is ten times higher than that due to snakebite [1]. An estimated 5000 deaths occur annually from scorpion stings worldwide [2,3].

Supportive care is the key component of management. Antivenom therapy with equine derived Fab fragments reduces the duration of symptoms. Centruroides antivenom is available in Mexico; in the United States, its use is restricted to that of an approved investigational drug [4].


Scorpions, which are grouped in the phylum Arthropoda, have a lobster-like body shape with seven sets of paired appendages: the chelicerae, the pedipalps (claws), four sets of legs, and the pectines (a pair of comb-like structures on the ventral surface) (figure 1). The segmented tail curves upward dorsally, ending in a terminal bulbous segment called the telson, which contains paired venom glands and the stinger. In the United States, a subaculear tooth on a small, slender scorpion is specific to Centruroides exilicauda (sculpturatus), also known as the bark scorpion (picture 1 and picture 2 and picture 3) [5,6].

Envenomation occurs through stinging, not biting. Scorpions clutch prey in their pedipalps (claws) and thrust the tail overhead to sting. Although envenomations are sometimes reported as bites, true scorpion bites have not been documented and would be inconsequential if they did occur. Scorpions can sting multiple times, although the first sting depletes or nearly depletes the telson of venom.

A characteristic physical property of scorpions is that they fluoresce when illuminated by ultraviolet light, as from a black light or a medical Wood's lamp (picture 4) [7]. This property is used in collecting scorpions for breeding or venom harvesting and in providing pest control. The fluorescent pigment in scorpion cuticle is most likely riboflavin.


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Literature review current through: Nov 2016. | This topic last updated: Thu Dec 11 00:00:00 GMT+00:00 2014.
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