What to Do if a Spider Bites Your Dog

Most spider bites—to both dogs and humans—aren’t cause for serious concern. Usually these small bumps heal on their own without any special attention. (Chances are you won’t even notice a bite 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:

• Do venomous spiders live in the United States?
• What dangerous spiders to watch for in different parts of the country
• Spider bite prevention in dogs
• How to identify a spider bite on your dog
• What to do if a spider bites your dog
• Additional canine first aid resources

1) Yes, the United States has venomous (or poisonous) spiders

The United States is home to a few species of venomous spiders.

Venomous versus poisonous spiders

To get technical, “venomous" is more accurate than "poisonous" here. Venomous means the spider injects venom into potential threats through fangs or stingers. Poisonous refers to animals that are harmful when ingested or touched.

Most venomous spider bites are mild

Most spider bites in the United States, even from venomous species, result in only 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 out of the blue—seek medical care right away. Practice good spider bite prevention techniques to reduce the risk of bites in the first place. (More about prevention and treatment in the next sections.)

2) What venomous spiders live in the US? What areas of the country have the highest spider bite risk?

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. That means the presence of venomous spiders in a particular region doesn’t necessarily suggest encounters with them are common.

In fact, the exact incidence of the below spider bites in dogs is unknown. That's actually a good sign: It means veterinarians don't see enough serious or lethal cases to collect data!

There's still a chance your pup has an arachnid encounter, though. Here are some species of spiders to watch for on your adventures.

Black Widow Spider bites — emergency — found in all states

Black widows are perhaps the most well-known venomous spiders in the United States. Found throughout the country, 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. Their venom can cause necrotic skin lesions in some cases—but severe brown recluse bites are thankfully rare, because these arachnids need counter pressure in order to break the skin. Brown recluse bites are most often found on dogs’ legs.

This species is brown with a distinctive violin-shaped marking on their back.

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. While bites in the US 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. They can still cause severe symptoms in some cases, though!

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. This species' range includes states like Florida, Texas, California, Arizona, and parts of the Gulf Coast. Their venom is less potent than the black widow—but even these little arachnids can cause serious effects, particularly in small dogs.

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.

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.

3) 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, tidy 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. 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 preferred 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 way you can 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.

4) How do you know if your dog was bitten by a spider?

Identifying a spider bite on your dog can be challenging. Symptoms vary depending on the type of spider, your individual dog's sensitivity (often based largely on body size), and the location of the bite.

Look out for these general signs to 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. Pay attention to your dog's typical body language so you're able to quickly identify signs of discomfort.

• Localized swelling: Spider bites often lead to localized swelling around the area of the bite. Swelling usually appears shortly after the bite occurs.
• Redness and skin irritation: The affected area may become red, inflamed, and irritated. It may also 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 and vocalization can also be a sign of pain.
• Visible bite marks: You may be able to see two small puncture marks at the site of the bite. These marks often aren't visible, though, especially if the spider bite was from a small species.
• Lethargy: Spider bites can cause lethargy or weakness in your dog. Your pup may appear tired, listless, or reluctant to move.
• Loss of appetite: A spider bite can lead to a loss of appetite in your dog.
• Vomiting or diarrhea: Some dogs 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 like the black widow.
• Seizures or tremors: Extremely rare—in cases of severe envenomation (like from a black widow bite), your dog may experience seizures or tremors.

5) 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 your dog may have been bitten, consult your veterinarian immediately. They can provide guidance on what to do next!

6) Further canine first aid resources

• Bee stings in dogs
• Ticks on dogs
• Preventing and treating heat stroke
• How to put together a dog first aid kit

Review of this Article

There is so much misinformation out there, and 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