Dogs and Spider Bites

3 min read
Jan 09, 2022

Fresh air, green grass, growing flowers, and insects are all common with the transition to the spring and summer seasons. Though you may be excited to get outside and enjoy the warmer weather, it's important to remember the dangers that can come with the change of seasons - spiders being one of them. 

Dangers of Spiders

There are more than 30,000 species of spiders in existence. Which means just about wherever you and your pets go, spiders can be found!

Most spider bites can cause a little more than painful swelling and should be treated like a bee or wasp sting since most cannot penetrate human or animal skin. However, a few species in the U.S. and throughout the world are venomous - meaning they inject toxin through fangs.

Not only can these arachnids inflict a painful bite, but they can cause serious side effects within 30 minutes to several hours of being stung. Our feline friends can also tend to get multiple bites due to a cat’s tendency to poke at and harass crawling creatures. 

In the United States, venomous arachnids include:

  • Widow (5 species)
  • Brown Recluse
  • Hobo spiders

Practice Safety and Avoidance

  • Use pet-safe insecticides to keep your house and yard spider-free.
  • Clear debris piles and leaves from spots in your yard where pets can access.
  • Prevent pets from sniffing under and around (meaning just don’t allow them access near) sheds, foundations, basements, and damp areas, including where hoses are stored, near water spigots and leaky plumbing -- basically cool, dark, damp locations.
  • Keep an eye out for any locations that seem to have many bugs gathered.  Spiders like bugs.
  • Bees can also pose a danger to pups as well, and nests may be found in similiar locations to spider's webs 

 Signs & Symptoms

  • Below are a few examples of signs and symptoms your pet may develop if bitten by a spider:
  • Swelling/Redness
  • Licking at or rubbing area of the sting
  • Pain
  • Fever
  • Rash
  • Chills
  • Breathing difficulty
  • Vomiting
  • Diarrhea
  • Lethargy
  • Muscle tremors or rigidness
  • Paralysis (including of the lungs)
  • Shock

What to Do

With your veterinarian’s permission, give your dog or cat the veterinarian approved amount of Diphenhydramine (Benadryl® antihistamine).  Benadryl® should not contain cetirizine, acetaminophen or pseudoephedrine, and do not give pets time release capsules. Gel caps are ideal as you can prick with a safety pin and squirt under your pet’s tongue. Liquid Benadryl® may contain xylitol, so keep paws off!

Spider toxin also contains acid, so applying baking soda or meat tenderizer (mix with a few drops of water to make a paste and apply to bite) may counteract the acidity.

If you suspect your dog or cat has been bitten by a venomous spider, apply a cold pack, restrain his movement (movement hastens the spread of venom) and get him quickly to your Veterinarian. If you can, take a photo of the spider to help your veterinarian identify the type of toxin and formulate treatment. 

Of course practicing precautions, and following safety guidance to avoid Spring-time injuries can also help.

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

About Spiders

Black Widow Spiders

Black Widow Spiders have a distinctive hourglass mark, typically red, but brown widows sport an orange hourglass. About ½" - 1" long (1.2cm - 2.54 cm) they prefer warm, dry climates and spin their webs in crevices and protected dark locations.

Both the male and female Black Widows possess a nerve toxin, but only the female has long enough fangs to penetrate a pet's skin. If you find a bite under your pet's fur, you may see two small puncture wounds 1-2mm apart. Muscle cramps, pain, increased heart rate, vomiting, diarrhea, and paralysis may follow.

Cats and small dogs may experience more severe effects due to the venom ratio to their smaller body size, but location of the bite, health, and age of the pet (even time of the year as venom is thought to be more potent during warmer months) all play a role.

If you suspect a bite, have your Veterinarian evaluate your pet immediately. Antivenin is available with mixed results, but pain medications and muscle relaxants can make your pet more comfortable. 

Brown Recluse (aka Fiddleback) Spiders

Brown Recluse (aka Fiddleback) Spiders hide in dark, secluded areas and their venom destroys tissue (necrosis). Approximately ½" - 2" long (1.2cm - 5cm), the Brown Recluse has a fiddle-shaped mark on its back. Mostly in the South-Central U.S. (Texas through Georgia) they can be found elsewhere.

When bitten, most dogs do not realize it, but after a while redness occurs often in the shape of a bullseye which is generally not noticeable on our pets. Seek veterinary assistance at once for pain medications and antibiotics.  Some wounds require surgical closure.

Hobo or Travelling Spiders

Hobo or Travelling Spiders can destroy your pet's tissue with their bite. Mostly in the Pacific Northwest, these large and aggressive brown spiders (often confused with the Recluse) build their webs in basements or at ground level. If a bite is suspected, get to the vet at once! 


Some are furry exotic pets but others found in the U.S. produce venom that can cause localized pain.

If your dog or cat ingests any of the stiff hairs covering the spider's legs, they can cause irritation, pain, drooling, and vomiting. Tarantula's actually "flick" hairs when threatened, so never allow pets too close.

If bitten, always err on the side of caution and have your Veterinarian check out your pet.  Be sure to check out what you can do to prevent ticks as well.

Consider Investing in Dog Insurance  

Looking for more ways to keep your pup happy and healthy? Consider investing in a dog insurance policy with MetLife Pet Insurance.1  Get your free quote today. 

Protect your Dog

Enroll in 3 Easy Steps

Nothing in this article should be construed as financial, legal or veterinary advice. Please consult your own advisors for questions relating to your and your pet’s specific circumstances.

Independence American Insurance Company (“IAIC”) is the insurance carrier for this product. IAIC, a Delaware insurance company, is headquartered at 485 Madison Avenue, NY, NY 10022. MetLife Pet Insurance Solutions LLC is the policy administrator authorized by IAIC to offer and administer pet insurance policies. This entity was previously known as PetFirst Healthcare, LLC and in some states continues to operate under that name pending approval of its application for a name change. The entity may operate under an assumed name and/or fictitious name in certain jurisdictions as approved, including MetLife Pet Insurance Services LLC (New York and Minnesota), MetLife Pet Insurance Solutions Agency LLC (Illinois), and such other assumed names or fictitious names approved by certain jurisdictions. 

Provided all terms of the policy are met. Like most insurance policies, insurance policies issued by IAIC contain certain exclusions, exceptions, reductions, limitations, and terms for keeping them in force. For costs, complete details of coverage and exclusions, and a listing of approved states, please contact MetLife Pet Insurance Solutions LLC.

1The Pet Safety Bible by Denise Fleck, Pet World Publishing, 2019.  Pages 165-167.

2The Pet Safety Bible by Denise Fleck, Pet World Publishing, 2019.