Arizona Bark Scorpion: Identification, Stings & Prevention
Stung? Call Poison Help: 1-800-222-1222 — poison center experts determine whether you need to go to the hospital. [2]
If a child 9 years or under, or weighing less than 70 lb (32 kg), is stung: call 911 or Poison Help, or take them to the nearest hospital immediately. [1]
Stings in children under 9 or in people with hypertension should be considered serious — call 911. Medical treatment is imperative for the young and the elderly, and a very small number of people may be allergic to the venom and have life-threatening reactions. [1]
This page is general information from the sources listed below, not medical advice.
Why this scorpion matters
- Only one of the 30 scorpion species found in Arizona is regarded as life-threatening: the bark scorpion (Centruroides sculpturatus). [2]
- Banner’s poison center calls it the most venomous scorpion in North America. [3]
- In 2021, Arizona’s two poison centers managed almost 5,500 scorpion stings. [4]
- A 2017 study cited by the University of Arizona found the highest sting incidence in Phoenix (up to 677 per 100,000 population) and Tucson (584). [1]
How to identify it
- Size — sources differ: 1 to 1.5 inches (Banner) [3]; about an inch and a half at maturity (Arizona Poison and Drug Information Center) [2]; a maximum of about 2.5 inches (National Park Service) [6]; adults 2–3 inches (University of Arizona [1]; Arizona-Sonora Desert Museum [5]).
- Color is not a reliable way to identify it, as it can vary. [3]
- Glows under UV light: bright green according to Banner [3], green according to the Desert Museum [5], bright bluish according to the National Park Service [6].
- It can climb almost anything except clean plastic or glass, and is often found on ceilings and cement walls. [3]
Sting symptoms
- Immediate local pain with minimal swelling; numbness and tingling are frequent and may travel across the body; the area may be very sensitive to touch, pressure, heat and cold. [2]
- Small children are at the highest risk of severe reactions and can show jerky body and wild eye movements [2]; Banner lists rapid, jittery eye movements and excessive salivation [3].
- Individual reactions vary greatly, but symptoms generally develop within 20 minutes and continue to worsen during the first 4 hours. Severe signs can include slurred speech, respiratory distress, excessive salivation and frothing at the mouth. [1]
First aid and treatment
- Call Poison Help (1-800-222-1222) first — poison experts determine whether you need to go to the hospital. [2]
- First aid: clean the site with soap and water, apply a cool compress (ten minutes on, ten minutes off, repeated as necessary), rest the limb in a comfortable position, and use over-the-counter medication as needed for minor discomfort. [2] [1]
- Approximately 90% of sting exposures reported to the Arizona Poison and Drug Information Center via the Poison Help Hotline are treated at home — after a certified specialist reviews the symptoms, and hotline staff may follow up. [1]
- Antivenom is available for severe cases in some hospitals: Anascorp® is the only available antivenom. [1]
- Deaths are rare: the University of Arizona fact sheet (2018 edition, originally published 2011) states that only four deaths have occurred in the United States “in the past 11 years”, without specifying the period. [1]
When and where they show up
- Most stings reported to the poison center occur at night during the warm summer months. [2]
- They are active for most of the year in low-desert areas, where nighttime temperatures above 70°F are ideal; from November to March they are less active, and in the coldest periods they cluster in groups in sheltered spaces. [1]
- In research cited by the University of Arizona, 95% of bark scorpions preferred hollow block walls as refuges. They enter under poorly fitted doorways, through window vents and via weep holes. [1]
How to keep them out
- Screen weep holes in brick veneer or weep screed with coarse steel mesh — don’t plug them, they ventilate the wall. Make door sweeps tight-fitting and caulk around eaves, pipes and wall penetrations. [1]
- Clear away debris, trash, logs and bricks, and fix holes and cracks in the house. [2]
- Move cribs and beds away from walls, consider placing crib legs in glass jars, and shake out shoes and clothing before wearing them. [3]
Scorpion treatment is included in some Arizona pest control plans and not in others — see pest control prices in Arizona. For spiders and other pests: DIY pest guides.
Frequently asked questions
What should I do if I am stung by a bark scorpion?
Call Poison Help at 1-800-222-1222: poison center experts determine whether you need to go to the hospital (Arizona Poison and Drug Information Center). If a child 9 years or under, or weighing less than 70 lb, is stung, call 911 or Poison Help, or go to the nearest hospital immediately; stings in children under 9 or in people with hypertension should be considered serious (University of Arizona). First aid includes washing the site with soap and water and a cool compress.
Is the bark scorpion dangerous?
It is the only one of the 30 scorpion species found in Arizona regarded as life-threatening, and small children are at the highest risk of severe reactions (Arizona Poison and Drug Information Center). The University of Arizona notes that most healthy adults can manage a sting without seeing a doctor, but that it is always advisable to call Poison Help (1-800-222-1222), as each individual has a unique response; an antivenom (Anascorp) exists for severe cases.
Do bark scorpions glow under a black light?
Yes. Banner’s poison center describes a bright green glow under UV light and the Arizona-Sonora Desert Museum a green glow; the National Park Service describes a bright bluish glow.
When are bark scorpions most active?
Most stings reported to the poison center occur at night during the warm summer months (Arizona Poison and Drug Information Center). The University of Arizona notes that in low-desert areas nighttime temperatures above 70°F are ideal, and that they are less active from November to March.
Sources
- University of Arizona Cooperative Extension, “Scorpions (AZ1768)” (2018) — acis.cals.arizona.edu
- Arizona Poison and Drug Information Center, “Scorpions” — azpoison.com
- Banner Poison and Drug Information Center, “Bark Scorpions” — bannerhealth.com
- Banner Health (press release), “Banner Poison and Drug Information Center warns bark scorpion stings on the rise” (June 2022) — bannerhealth.com
- Arizona-Sonora Desert Museum, “Bark Scorpion” — desertmuseum.org
- U.S. National Park Service, “Arizona Bark Scorpion” — nps.gov
PestPinpoint is not a medical provider or a pest control company. In an emergency, call 911.