Nancy Onisko, D.O.
Emergency Medicine
Warm weather is coming, and while that means time outdoors and fun with friends and family, it also increases the chances of encountering snakes and spiders.
The good news is that in Texas, only about 10% of the 105 species or subspecies of snakes native to the state are venomous. And only two types of spiders that live in Texas are venomous to humans.
My distinction above – “natural to the state” – is intentional. Depending on the law in their local jurisdiction, a Texas resident might be able to own an exotic, non-indigenous snake with just a $20 permit from Parks and Wildlife. Owners of such snakes should mind proper snake handling and care techniques to avoid getting bitten or putting someone else in danger.
Snakes natural to Texas that you’ll want to avoid include nine types of rattlesnakes (common around Austin and Houston) and cottonmouths and copperheads (more common in the Dallas-Fort Worth area). Coral snakes are found in the southeastern half of Texas. Venomous spiders include the black widow and brown recluse, both of which are found throughout the state.
I’m a physician in UT Southwestern’s Emergency Department and Division of Medical Toxicology, where we treat about one to five snake bites a month in season (May-September). Venomous spider bites are much more rare.
I’m also a self-proclaimed “toxinology nerd” – toxinology focuses on venomous animals and poisonous plants, and it is a subspecialty of toxicology, which is the study of toxins and poisons. My research has provided insights into the behavior of venomous animals and how they respond to human intrusion.
Contrary to some popular beliefs and deep-seated fears, snakes and spiders don’t go out of their way to bite humans. Often, their bites are defensive in nature and occur when the snake or spider perceives a threat or is provoked. Some defensive bites do not require medical attention because they transfer little to no venom.
Bites that release venoms can cause painful symptoms and even death – however, that is relatively rare. Each year in the U.S., there are 5-10 deaths directly related to the venom of a snake. There is maybe one death per decade directly related to a spider bite. Due to advancements in medicines such as antivenoms, U.S. patients typically have good outcomes.
Most venomous bites are preventable, treatable, and overwhelmingly survivable. If you think you’ve been bitten by a venomous snake or spider, it’s important to remain calm and follow three steps to slow venom spread and aid in your speedy and full recovery.
What to do after a snake or spider bite
1. Identify what bit you
Venomous snakes in Texas vary in preferred habitats, color, and skin markings:
- Copperheads: Found in areas with grass, dirt, or prey, these snakes prefer less populated areas. However, more and more humans have taken over their habitat, so you will find them increasingly in urban environments. Their skin has broad, alternating dark and light patterns that resemble hourglasses.
- Cottonmouths: Found in and near water, they are dark brown with light brown and dark brown patterns. When threatened, it will open its mouth, revealing a white interior.
- Rattlesnakes: There are nine varieties of rattlesnakes in Texas. Found most commonly in grasslands, scrub brush, swamps, and deserts, they vary in color and patterns. Rattlesnakes can be identified by the rattles at the tip of their tails.
- Coral snakes: Found in forests, canyons, and coastal plains, they are slender and relatively short (2 1/2 feet or less) with black, yellow, and red rings.
Copperheads, cottonmouths, and rattlesnakes are all pit vipers, and they share four common characteristics:
- Thin, black, vertical pupils like in a cat’s eyes
- Triangular-shaped heads with holes behind the eyes to detect prey
- Thick bodies and heads, with a neck that narrows at the skull base
- Hollow fangs that rotate forward
Venomous spiders also have distinct characteristics:
- Brown recluses: They are singularly brown – without any bands, mottling, or stripes – with a darker violin-shaped mark on the cephalothorax (the portion of the body to which the legs attach). These spiders are known for their unusual eyes; while most spiders have eight eyes arranged in rows of four, recluses have six equal-sized eyes arranged in three pairs at the front of the cephalothorax.
- Black widows: Shiny black with a bright red or orange hourglass-shaped marking on the underside of their round abdomen, they have eight eyes arranged in two rows.
Though it may be difficult to identify a snake or spider that bit you, taking a picture of the animal – without getting too close again – or providing a detailed description can help us determine treatment options.
Though some patients have brought dead snakes to the emergency department, note that freshly killed snakes may be able to bite and inject venom – so, handle with care. Don’t risk bringing a live snake to the hospital.
2. Keep the bite clean, unbound, and free from irritation
In the movies, it has become cliché to treat snake bites by sucking out the venom. That’s not a good idea – and it can cause more harm than good. Improper care can introduce infection and cause pain, swelling, and venom spread.
Avoid following myths about venomous bite care. If you are bitten, DO NOT:
- Tie a tourniquet or constrictive band around the wound.
- Apply ice, heat, or electricity to the bitten area.
- Cut an “X” in the wound and try to suck out the venom.
- Use venom extraction devices; they don’t really work and are marketed on myth instead of medicine.
Follow these proven safety steps if you are bitten:
- Wash the area with soap and water.
- Keep the wound immobilized with a splint if possible.
- Try to keep the limb elevated to the level of the heart until you reach a facility with antivenom.
- Remove rings, watches, and constrictive clothing from the area.
- Call 911 or go to the nearest emergency department. Severe symptoms can develop quickly.
3. Seek emergency care for suspected venomous bites
For snake bites: Call 911 or go to the emergency department. Your doctor will consult with poison control specialists to determine whether antivenom – a drug that binds with the actual venom and deactivates it – is needed. If antivenom is administered, you’ll be admitted to the hospital for observation for one or two days. If you experience swelling or abnormal lab work, you might be given additional doses.
For spider bites: Visit your primary care doctor if you have mild or local symptoms, which may include:
- Brown recluse bites: Skin lesions or rashes, including deep blue or purple areas – with a red ring – around the bite; body aches, and mild pain. If more systemic symptoms such as fever, chills, and blood in the urine develop – particularly in children – go to the nearest emergency department.
- Black widow bites: Redness and swelling; abdominal cramps; muscle spasms; and pain that radiates through the body
If your symptoms are more sever, you should seek emergency care.
Antivenom is rarely administered for venomous spider bites. Brown recluse bites can cause tissue death in areas ranging from a small area to a large patch – treatment is a longer-term process that can be managed by a primary care doctor and/or a dermatologist. It can take months to heal from a brown recluse bite, but a black widow bite – which, despite the name, is rarely fatal – should be fully healed within two weeks.
Tips to prevent snake and spider bites
Recent research suggests that our fear of snakes and spiders was inherited through cultural conditioning. Fear often leads to overreaction, which puts the animal on the defensive and can lead to bites.
Remember: Humans are not a snake or spider’s preferred prey. If you spot one, back away and leave it alone. Follow these steps to avoid snakes and spiders and potentially prevent bites:
- Be vigilant in storage spaces such as closets, basements, cellars, attics, or sheds. Dry, dark spots that are infrequently disturbed by humans are favorite hideaways for spiders.
- Carefully inspect stored items, such as boxes and bags of clothes. Spiders like these small, still places.
- Keep your grass cut short and limit potential hiding spots, such as firewood stacks.
- Be careful when hiking, running, or walking in grassy areas. Snakes like tall grass and places where they can hunt without being seen.
- Use the buddy system to provide extra snake surveillance and protection.
- Wear sturdy shoes and long pants, particularly when hiking, to limit the risk of a bite penetrating the skin.
Though many people fear snakes and spiders, these creatures would just as soon never encounter us either. If you cross paths and get bitten, the risk of long-term problems or death is extremely low. With proper planning and fast action after a bite, you can enjoy a season free from worry about snakes and spiders.
Visit the emergency department for venomous snake bites. For non-emergency snake or spider bite evaluation, call our toxicology clinic at 214-590-1603 or request an appointment online.
