Arizona is home to 30 to 50 species of scorpions inhabiting the state’s various desert environments. While most pose little threat beyond a painful, localized sting, the Arizona Bark Scorpion (Centruroides sculpturatus) is the only species in North America considered medically significant. Its presence requires caution and a clear understanding of its distinct characteristics. Recognizing this specific species is the first step in ensuring safety for residents and visitors.
Identifying Arizona’s Most Venomous Scorpion
The Arizona Bark Scorpion is responsible for nearly all serious envenomations in the region. It is small, typically measuring one to three inches, and is difficult to spot due to its pale straw or yellowish-tan coloration.
A key identifier is its slender body structure. Unlike less dangerous scorpions, the Bark Scorpion possesses thin, delicate pincers and a noticeably slender tail (metasoma). When at rest, the tail is often coiled tightly to the side or rests parallel to the surface.
This scorpion is nocturnal and an exceptional climber, distinguishing it from ground-dwelling relatives. It is frequently found on vertical surfaces like walls, ceilings, and inside homes. During the day, it seeks refuge in cool, dark crevices, including tight spaces within human dwellings.
What to Expect After a Sting
A sting causes an immediate, intense, and sharp burning sensation at the site of injection. The venom is a potent neurotoxin that quickly leads to widespread numbness and tingling, which may travel throughout the affected limb or body. Localized muscle twitching is also a common initial reaction.
Healthy adults usually experience severe pain for 24 to 72 hours. However, the sting is most dangerous to small children, the elderly, and those with underlying health conditions. In these vulnerable groups, severe neurotoxic symptoms can develop quickly, requiring immediate emergency medical care.
Severe reactions involve systemic symptoms such as difficulty swallowing, excessive drooling, slurred speech, and involuntary muscle contractions. Young children may exhibit opisthotonus (hyperextension of the neck and spine) or show rapid, uncontrollable eye movements. Seeking guidance from a poison control center is recommended to monitor symptoms and determine if antivenom treatment is necessary.
Essential Prevention and Exclusion Steps
Reducing the risk of an encounter begins with habitat modification and sealing potential entry points into the home. Since scorpions seek harborage, remove outdoor debris like woodpiles, large rocks, and construction materials from the house perimeter. Also, trim back shrubs and trees that touch the roof or exterior walls, preventing scorpions from using them as bridges to access the structure.
Preventing indoor entry requires diligent sealing of the home’s envelope, as scorpions can squeeze through cracks as small as one-sixteenth of an inch. Install tight-fitting door sweeps on all exterior doors and use caulk to seal cracks in the foundation or around utility penetrations. Inside the home, shaking out shoes, clothing, and towels before use can prevent accidental stings.
A UV black light can be used after dark to inspect the yard and home. The scorpions’ exoskeletons naturally fluoresce a bright blue-green under this light, making them easy to spot.