Spider Bites on Dogs: Signs, Symptoms, & Treatment

Although nearly all spiders in the U.S. are venomous, most spider bites on dogs aren’t cause for concern because only a few spiders have mouths large enough to penetrate the skin and release venom. The groups of spiders that can have problematic bites include widow spiders and brown recluse spiders.¹

Keep reading for more information on symptoms of spider bites and how bites are treated for dogs.

Spider Bite Symptoms in Dogs

Dogs bitten by a spider may start developing signs within a few minutes, though some symptoms may take up to eight hours to appear. The signs and symptoms your dog experiences depend on the type of spider, but may generally include:^1,2

• Swelling or redness at the site
• Licking at or rubbing the area
• Pain or agitation

If it’s a brown recluse spider bite on your dog, symptoms can also include:^1,2

• A bull’s-eye pattern around the bite
• A blister or ulceration (open wound)
• Darkening of the skin tissues in the center of the bite
• Fever
• Lethargy
• Vomiting

If it’s a black widow spider bite on your dog, general symptoms can occur alongside more progressed symptoms, like:^1,2

• High blood pressure
• Difficulty breathing
• Vomiting or diarrhea
• Muscle tremors or rigidness
• Partial paralysis

Types of Spiders With Potentially Dangerous Bites

There are more than 48,000 species of spiders in existence — just about wherever you and your pets go, spiders can be found!² To help you keep your dog safe, here are some more specifics about common spiders.

Black widow spiders

Black widow spiders have a distinctive hourglass mark under their abdomen that’s usually red but can be orange. At about 1.5" long, they prefer tropical and temperate climates. They tend to spin their irregular-shaped webs in crevices and protected dark locations — like wood piles, cluttered basements, sheds, crawl spaces, under stones, and in hollow stumps.^1,2,3

Widow spiders can be found around the world. Five species, including the black widow, living throughout the U.S.^1,2,3

Their venom is one of the most potent toxins by volume. However, they can sometimes control the amount they release, so not all bites result in the release of venom.¹

Brown Recluse (aka Fiddleback) spiders

Brown recluse (aka Fiddleback) spiders are approximately 0.25" – 0.5" long and have a characteristic dark brown fiddle-shaped mark on their back. In the U.S., they’re mostly found in central and southern areas, but some species have been identified as far west as New Mexico, Arizona, and California.^1,2,4

Brown recluse spiders like to hide in dark, warm, secluded areas, like rarely-used closets, attics, woodpiles, tire piles, between rocks, or in building crevices.⁴

Most dogs don’t realize they’ve been bitten by a brown recluse, since it’s usually not painful. However, the venom contains enzymes that can eventually destroy tissue (necrosis).

Reactions typically happen at the bite site, in contrast to black widow bites, which send venom spreading to other parts of your dog’s body. If reactions from the brown recluse venom do spread, your dog may experience blood clotting and kidney issues.^1,2

Tarantulas

Tarantulas can be found outdoors in the Southwest U.S. You may even have one as a pet!⁵ While the American tarantula is generally harmless, the Asian and African species’ venom can cause localized pain and swelling where they bite.¹

But you might be surprised to learn that most tarantulas don’t typically utilize biting. Instead, the stiff hairs covering the spider's back and legs can be shot out in defense, causing irritation or an allergic reaction.^1,5

Even though this spider isn’t as alarming as black widows or brown recluses, it’s still a good idea to keep a safe distance between tarantulas and your dog.

Treating Spider Bites on Dogs

Since the spider might not have stuck around long enough for you to identify it, treating spider bites at the vet often involves supportive care of symptoms. For instance, your vet may give your dog muscle relaxers and pain relievers for black widow bites, with antivenom used when necessary. Recovery from a bite can take several days or more, depending on your dog’s condition.¹

For brown recluse bites, your vet will likely restrict your dog’s movement and apply a cold compress to help prevent the spread of venom and necrosis. No antivenom is available in the U.S. Aftercare for the wound is key in helping it heal. If infection occurs, your dog may be put on antibiotics. Recovery from a bite can take weeks to months, depending on the wound.^1,2

With your vet’s permission, non-venomous bites can typically be treated similar to an insect bite with a cold compress, over-the-counter (OTC) anti-itch medicine, and an antihistamine like Benadryl®.

Always speak with your veterinarian first before treating your pet with any type of medications.

How To Prevent Spider Bites on Dogs

Some of the best things you can do to help prevent harmful spider bites for your pup is monitoring their activity outside — especially around areas spiders like to call home — and keeping your outdoors spaces and home clean. This might look like:

• Clearing debris piles (like wood, tires, rocks, or scrap metals) and leaves from spots in your yard where pets can access
• Preventing pets from sniffing under and around sheds, foundations, basements, and damp areas, including where hoses are stored, near water spigots, and leaky plumbing
• Regularly cleaning your home and doing deep cleans every so often to prevent spiders from gathering
• Keeping an eye out for any locations inside and outside that seem to have many spider webs

MetLife Pet Insurance Can Help With Vet Bills

Whether it’s a quick exam to make sure your dog didn’t get bit by a harmful spider or treatment for a venomous bite, your wallet can take a hit from unexpected vet bills. But that’s where having a MetLife Pet dog insurance policy can help!

Portia, a young dog from Arizona, was bit by a spider while playing with her family in the yard. After taking her to the vet for an exam, it was ruled non-venomous, and she was given medication for the swelling and pain. These meds cost over $80, but with their MetLife Pet policy, Portia’s pet parents were reimbursed nearly the entire cost.⁶

Just like these members of the Metlife Pet family, you can help protect your pet from accidents while saving money on vet bills. Get your free, personalized quote today.