Scorpion stings — although painful — are mostly harmless. About 30 of the estimated 1,500 species of scorpions can inflict potentially fatal stings. In the United States, only the bark scorpion, found mainly in the desert Southwest, has venom potent enough to cause severe symptoms. Elsewhere, lethal scorpion stings occur predominantly in Mexico, South America, and parts of Africa, the Middle East and India.

Scorpion stings are most serious in young children, older adults and pets. In the United States, healthy adults usually don't need treatment for scorpion stings, but if your child is stung, seek immediate medical care.

Most scorpion stings in the United States cause only minor signs and symptoms, such as pain and warmth at the sting site. The venom of the bark scorpion, native to Arizona, New Mexico and the California side of the Colorado River, is more toxic and can be life-threatening, particularly in children.

Mild signs and symptoms might include:

  • Pain, which can be intense
  • Numbness and tingling in the area around the sting
  • Slight swelling in the area around the sting

More-severe signs and symptoms might include:

  • Muscle twitching or thrashing
  • Unusual head, neck and eye movements
  • Drooling
  • Sweating
  • Vomiting
  • High blood pressure (hypertension) or low blood pressure (hypotension)
  • Accelerated heart rate (tachycardia) or irregular heart beat (arrhythmia)
  • Restlessness or excitability or inconsolable crying (in children)

When to see a doctor

It's always best to be safe. If you or your child is stung, follow these guidelines:

  • If you're concerned about a scorpion sting — even if your reaction is minor — first call your local poison control center for advice. To reach a poison control center in the U.S., call Poison Help at 800-222-1222.
  • Get immediate medical care for any child stung by a scorpion.
  • If you've been stung, get prompt care if you begin to experience widespread symptoms.
  • Seek medical attention right away if you or your child is stung while traveling in another country.

Scorpions are arthropods — a relative of insects, spiders and crustaceans. The average scorpion is about 3 inches (7.6 centimeters) long, but different species can be smaller or larger. Scorpions have eight legs and a pair of crab-like pinchers. They sting rather than bite, using the stinger in their tails. The venom itself contains a complex mix of toxins that affect the nervous system (neurotoxins).

Scorpions are nocturnal creatures that resist stinging unless provoked or attacked. They can control the amount of venom they release — depending on how threatened they feel — so some stings may be almost entirely venomless.

Certain factors can increase your risk of a scorpion sting:

  • Location. In the United States, scorpions mainly live in the desert Southwest, particularly Arizona. Worldwide, they're found most often in Mexico, northern and southern Africa, South America, the Middle East and India.
  • Environment. Bark scorpions live under rocks, logs and tree bark — hence, the name — and you're especially likely to encounter them when you're hiking or camping. Bark scorpions are also the most common house scorpion, hiding in firewood, garbage pails, bed linen and shoes.
  • Season. Scorpions are most active in spring and summer, when nighttime temperatures hover above 70 F (21 C).
  • Travel. Not only are you more likely to encounter dangerous scorpions while traveling in developing countries, you might bring them home with you. Scorpions can hide in clothing, luggage and shipping containers.

As with stinging insects, such as bees and wasps, you can have an allergic reaction to a scorpion sting — sometimes severe enough to be life-threatening (anaphylaxis). Signs and symptoms are similar to those of bee stings and can include hives, trouble breathing, and nausea and vomiting. An allergic reaction may be wrongly attributed to the venom, which can cause different but also dangerous symptoms.

The very old and the very young are most likely to die of untreated venomous scorpion bites. The cause is usually heart or respiratory failure occurring some hours after the sting. Very few deaths from scorpion stings have been reported in the United States.

If you can find the scorpion that stung you or your child, bring it with you to the hospital. Identifying the type of scorpion may make treatment easier.

Your history and symptoms are usually all your doctor needs to make a diagnosis. If you have severe symptoms, you may have blood or imaging tests to check for the effects of the venom on your liver, heart, lungs and other organs.

Most scorpion stings don't need medical treatment. But if symptoms are severe, supportive care in a hospital is usually required. In addition to bed rest, this might include sedatives for muscle spasms and intravenous drugs to manage elevated blood pressure, agitation and pain.

A new antivenin (Anascorp) is widely available in Mexico, where the mortality rate from bark scorpion stings in high. It's used less in the United States because of the low mortality risk from bark scorpion stings.  However, it's recommended that people with severe symptoms receive the antivenin.

If a scorpion stings you or your child, follow the suggestions below. Healthy adults may not need further treatment, and these tips can help keep children safe until they see a doctor:

  • Clean the wound with soap and water.
  • Apply cold compresses to the affected area to ease the pain and slow the venom's spread. This is most effective in the first two hours after a sting occurs.
  • Keep the affected limb raised to the level of your heart.
  • Try to stay calm and quiet so that the poison spreads more slowly.
  • Don't consume food or liquids if you're having difficulty swallowing.
  • Over-the-counter pain relievers, such as ibuprofen (Motrin IB, Chlidren's Motrin, others), can help ease discomfort. But avoid using narcotic pain medications, which can suppress breathing.

Check your or your child's immunization records to be sure a tetanus vaccine is up to date.

Scorpions tend to avoid contact. If you live in an area where scorpions are common, prevent chance meetings by doing the following:

  • Remove trash, logs, boards, stones, bricks and other objects that would make good hiding places for scorpions from around your home.
  • Keep grass closely mowed, and prune bushes and overhanging tree branches, which can provide a path to your roof for scorpions.
  • Caulk cracks, install weatherstripping around doors and windows, and repair torn screens.
  • Don't store firewood inside your house.
  • When hiking or camping, wear long sleeves and pants and check your sleeping bag for scorpions before you crawl in. Check your clothing and shake out your shoes before you put them on. Always wear shoes.
  • When traveling in other countries — especially if you're camping or staying in rustic accommodations — shake out your clothing, bedding and packages often and sleep under a mosquito net. If you have a known allergy to insect stings, carry an epinephrine injector, such as EpiPen.

If you do find a scorpion near your home or campsite, use tongs to gently remove the scorpion away from people.

Jan. 23, 2014