Spider Bites on Dogs: Side Effects, Treatment and Protection

ElleVet Dog outside

When we think of variations of bugs and insects and how they may potentially harm our dog, our minds will usually start with fleas and ticks. These are undoubtedly the most common type of nuisance, with mostly every dog out there receiving yearly and or monthly applications (such as Bravecto) to protect them from flea and tick infections.

However, a potentially more dangerous species doesn’t seem to be discussed as much in the animal health industry. The harmful species we are referring to is none other than…. spiders. Spiders of any kind send a chill up many spines, even reading the word can leave us with uneasy feeling. And to be scientifically accurate, spiders are actually classified as “arachnids”, not insects (ticks also fall in this category). 

Unfortunately, spider bites can be more common in dogs than you may think, and if it does happen to your furry friend, they will not start shooting webs and swinging from buildings (wishful thinking). In all seriousness, some spider bites can pose a serious threat to our dogs. So, how do we handle it and make sure we are doing everything possible to protect our dogs? 

Table of Contents

  1. Side Effects
  2. Treatment
  3. Protection

Side Effects of Spider Bites in Dogs 

All spiders are not created equally, and the fact is, some species of spiders are far more dangerous to dogs (and humans) than others. Although almost all species of spiders are technically venomous, the Black Widow Spider, the Brown Recluse Spider and the Hobo Spider are the only 3 dangerously poisonous spiders found in North America. Nevertheless, some spider bites can still cause some moderate issues in dogs. They can cause redness, swelling, itching and pain, while some can be totally undetectable and harmless. 

Side Effects: 

  • Diarrhea 
  • Anxiousness
  • Trouble Walking or Standing
  • Itchiness
  • Drooling
  • Pale Gums
  • Tremors
  • Vomiting 
  • Paralysis
  • Intense Muscle Pain
  • Abnormal Blood Pressure 
  • Blistering 

While these side effects usually only rear their head during more severe bites and reactions caused by a potently venomous species, it is important to know the signs to look for. If you live in North America, and your dog is showing any of these symptoms after you discover some kind of bite on their skin, and it is determined to be a spider bite, you can assume that it has been caused by the Black Widow, Hobo, or Brown Recluse spider. The neurotoxins found in these spiders’ venom are the root cause of some of these major side effects. So, while its comforting to know that these intense side effects are much less common and only caused by especially poisonous species, it is still valuable to educate yourself on what these spiders and their bites may look like, and what signs to look out for in your dog. Especially if you live in area known to be inhabited by Black Widow, Brown Recluse, or Hobo spiders. If you think your dog may have been bitten by a poisonous spider, seek medical attention immediately. 

What Treatment is Used for Severe Bites?

Most of the time, your veterinarian will prescribe your dog an antibiotic or antiseptic to prevent secondary infections caused by venomous spider bites. Again, it is important to remember that these actions are usually only taken in cases where the dog has been bitten by an especially poisonous species of spider. 

Dog Prescription Bottle

Are Certain Dogs at More Risk?

These dangerous spiders don’t discriminate, so no breed of dog is at more or less risk necessarily. However, older dogs and dogs with high blood pressure can experience more severe symptoms and reactions due to their weakened immune system. 

The good news is these spiders are not out hunting for your dog. They will only bite if they feel threatened in some way, and most of time it is just a case of “wrong place, wrong time”. Your dog can accidentally run through a web, or unknowingly sit down on one of these poisonous spiders. This is where a bite can happen. 

What Can We Do to Protect Our Dogs?

Like we mentioned, spiders are not actively looking to bite and harm your dog. They aren’t exactly easy to locate, unless you’re looking closely for them, and they aren’t going to walk up and ask if it’s OK to bite your dog. What we can do is take precautions. 

Spiders will usually make their webs in undisturbed areas, like the corner of an attic or basement. If your dog is spending time in any of these areas or has spent a lot of time outside running around lately, check for spider bites the same way you would check them for ticks. If you or a family member discovers a spider infestation in or around your property, this would also be a good time to check your dog for any suspicious bumps or bite marks. If you do discover a spider bite, or an unidentified area of concern, you can clean the area with soap and water and consult your veterinarian for next steps


The ElleVet Team
844-673-7287
[email protected]

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