Most spider bites — on both dogs and us humans — aren’t cause for serious concern. Usually they’ll heal on their own without any special attention. (Chances are you won’t even notice you were bitten in the first place!)
Sometimes, though, a spider bite does require treatment or even immediate medical attention. Here’s what you need to know to keep your pup safe on all your adventures!
Does the United States have venomous or poisonous spiders?
The United States is home to a few species of venomous spiders. To get technical, “venomous” is officially more accurate than “poisonous” here — venomous means the spider injects venom into potential threats through fangs or stingers, while poisonous typically refers to animals that are harmful when ingested or touched.
Most spider bites in the United States, even from venomous species, result in mild symptoms. Phew! Don’t get too complacent, though: If you suspect your dog has been bitten by a venomous spider or they experience severe symptoms, seek medical care right away. Practicing good spider bite prevention techniques can help reduce the risk of bites in the first place. (Read on for more about prevention and treatment in the next sections.)
What venomous spiders live in the US? What areas of the country have the highest spider bite risk?
Know that presence of venomous spiders in a particular area doesn’t necessarily mean that encounters with them are common. Spiders typically prefer quiet, undisturbed areas. They’re usually not aggressive toward humans or our dogs — most spider bites are the result of accidental contact or disturbance.
Here are some species of spiders to watch for:
Black Widow Spider bites — emergency — found in all states
Black widows are perhaps the most well-known venomous spiders in the United States. They are found throughout the country, though they’re most common in warmer southern climates. Black widows are known for shiny black bodies with a distinctive red hourglass shape on their abdomen.
Brown Recluse Spider bites — emergency — Midwest and South
Brown recluse spiders are found primarily in the Midwest and southern United States. They are brown with a distinctive violin-shaped marking on their back. Their venom can cause necrotic skin lesions in some cases, though severe bites are thankfully pretty rare because brown recluses need counter pressure in order to break the skin. This means brown recluse bites are most often found on dogs’ legs.
Chilean Recluse Spider bites — emergency — some Southern states
Chilean recluse spiders are most commonly found in South America, but they can make their way to the southern United States. They’re more venomous than their brown recluse relatives — so while bites are rare, they need to be taken seriously right away.
Red Widow Spider bites — possible emergency — found in Florida
Red widow spiders are primarily found in the southeastern United States, particularly in Florida. They have a limited range compared to other widow spider species so serious bites are less common, but they can still cause severe symptoms in some cases. Red widow spiders are known for their striking red or reddish-brown coloration. Like other widow spiders, they have a distinctive hourglass-shaped marking on the underside of their abdomen.
Brown Widow Spider bites — possible emergency — some Southern states
Brown widow spiders are commonly found in the southern and southwestern parts of the country. Their range includes states like Florida, Texas, California, Arizona, and parts of the Gulf Coast. Brown widow spiders are typically light to medium brown in color and have an hourglass-shaped marking on the underside of their abdomen. This marking is usually orange, yellow, or even white. They are smaller than black widow spiders, with a body length of about 1/4 to 1/2 inch. Their venom is less potent than the black widow but can still cause serious effects particularly in small dogs.
Hobo Spider bites — usually not emergency — West
Hobo spiders are found in the Pacific Northwest and parts of the West. While there have been concerns about their venom, they are not considered highly dangerous. Their bites usually result in mild symptoms.
How can you prevent your dog from being bitten by a spider?
The best treatment is prevention. Here are some steps you can take to help protect your dog from spider bites!
Perform regular home cleaning and maintenance
Keep your home, especially areas where your dog spends a lot of time, clean and clutter-free. Regular cleaning can help eliminate hiding spots for spiders.
Inspect outdoor play areas
Before allowing your dog to play in outdoor areas, inspect the environment for spider webs, nests, or hiding spots. Remove any spider webs or nests you find.
Store firewood and debris away from living spaces
Keep firewood, garden debris, and other clutter away from areas where your dog spends time, as these can be attractive hiding spots for spiders.
Check your dog’s bedding
Regularly inspect your dog’s bedding, crate, and sleeping areas for signs of spiders or spider webs. Shake out and clean bedding to remove any potential hiding spiders.
Be mindful of spiders’ favorite environments
When walking your dog in wooded or natural areas, be cautious around logs, rocks, and other potential spider habitats. Keep your dog on a leash if you’re uncertain to prevent them from sticking their nose into spider hiding spots.
Educate yourself on local spiders
Learn about the types of spiders in your area and their habitats. This knowledge can help you identify potential risks and take appropriate precautions.
Supervise your dog
Keep an eye on your dog while they are exploring new environments, especially in unfamiliar outdoor settings. This can help you intervene if your dog encounters a spider.
Spider proof your home
Install screens on windows and doors to keep spiders and other insects out of your home. Seal cracks and gaps in walls and doors to prevent spiders from entering.
How do you know if your dog was bitten by a spider?
Identifying a spider bite on your dog can be challenging — symptoms can vary depending on the type of spider, your individual dog’s sensitivity (often based largely on body size), and the location of the bite. There are some general signs you can look out for, though, that will help you decide what to do next for treatment.
Spider bite symptoms in dogs
If you notice any of the following symptoms, consider the possibility of a spider bite and consult your veterinarian.
- Localized swelling: Spider bites often lead to localized swelling around the area of the bite. The swelling may appear shortly after the bite occurs.
- Redness and skin irritation: The affected area may become red, inflamed, and irritated. It may be warm to the touch. These symptoms of spider bites can appear like a range of other allergic reactions.
- Pain or discomfort: Your dog may show signs of muscle pain, joint pain, or other discomfort. They may lick, scratch, or chew at the area of the bite. Whining or vocalization can also be a sign of pain.
- Visible bite marks: In some cases, you may be able to see two small puncture marks at the site of the bite. These marks may not always be visible, especially if the spider bite was from a small species.
- Lethargy: Spider bites can cause lethargy or weakness in your dog. They may appear tired, listless, or reluctant to move.
- Loss of appetite: A spider bite can lead to a loss of appetite in your dog. They may not be interested in eating.
- Vomiting or diarrhea: Some dogs may experience gastrointestinal symptoms such as vomiting or diarrhea as a result of a spider bite.
- Difficulty breathing: In rare and severe cases, spider venom can cause difficulty breathing or other respiratory distress. This is more likely with certain venomous spiders.
- Seizures or tremors: Extremely rare, but in cases of severe envenomation (like from a black widow bite), your dog may experience seizures or tremors.
What should you do if your dog was bitten by a spider?
If you’re able to capture the spider that bites your dog, keep it in a tight jar or other secure container and show it directly to your vet. This will help determine what treatment your pup needs.
If your dog was bitten by a non-venomous spider:
If you know your dog’s bite wasn’t venomous, or their symptoms are very mild, keep a close eye on their condition while trying to alleviate their discomfort. You can treat itching or mild swelling with a cool compress (like a soft ice pack wrapped in a towel) or pet-friendly pain reliever cream.
If your dog was bitten by a venomous spider:
Try to stay calm (we know, easier said than done) and keep your dog as still as possible as you get them to your nearest emergency vet. Unnecessary movement can spread venom through the bloodstream.
Once you arrive, follow the guidance of your veterinarian. They may recommend treatment for spider bites ranging from pain relief (often through oral or intravenous pain medication), muscle relaxers, antihistamines, or antivenom depending on the severity of the bite and the type of spider involved.
They’ll also monitor your dog’s vital signs like heart rate and watch for other clinical signs of long-term problems.
If you aren’t sure what kind of spider (or insect) bit your dog:
It’s always better to be safe than sorry. If you live in an area with venomous spiders (so really, anywhere in the United States but especially southern states) and suspect that your dog may have been bitten, consult your veterinarian immediately. They can provide guidance on what to do next!
Review of this Article
There is so much misinformation out there, we want to make sure we only provide the highest quality information to our community. We have all of our articles reviewed by qualified, positive-only trainers or veterinarians.
This is the professional that reviewed this article:
Amber Holly, BS, RVT, LVT