Spider Bite in Dogs: Symptoms and Treatment

Most of us flinch at the sight of a spider but our furry friends don’t seem to have that problem. On the contrary, curious beings that they are, dogs are wired to inspect every creepy crawly or insect they come across. With a tap of the paw, a sniff, and a nudge. So, as a pet parent, you need to learn how to recognize, learn, and prevent spider bite in dogs. 

Given that there are 45,000 varieties of spiders in the world — over 3,000 of which are found in the US alone — the possibility that a spider bites a dog isn’t that far-fetched. Responsible pet parenting entails being prepared for every eventuality. That’s why I’ve put together this guide on dealing with a spider bite in dogs. 

How to Recognize Spider Bite in Dogs 

The reason I decided to talk about spider bites in our canine companions is that not long ago I noticed what seemed like an insect bite on my dog’s belly. We were on a short trip to an eco-resort and earlier in the day, I had spotted a nasty-looking bright blue spider just outside our room. This had me wondering sick with worry, “How do I know if my dog has been bitten by a spider? What are the tell-tale signs of a spider bite on dog belly?” 

Thankfully, the bite didn’t seem to bother my pooch, and it was soon forgotten. It healed on its own within a couple of days too. That’s the good thing about a spider bite in dogs. 9 times out of 10, it is not a cause for concern — unless your dog has an allergic reaction to it. Even so, it helps to be aware of the symptoms of spider bite in dogs.  

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Symptoms of Spider Bite in Dogs

Most spider varieties are non-venomous and their bites don’t cause any more discomfort than that of an ant or a mosquito. This is because spiders’ mouths are too weak and fangs too short to pierce your dog’s skin. Besides, a large variety of spiders are non-venomous or the toxins aren’t typically strong enough to cause any health risks to dogs. If a spider does manage to bite a dog, the presentation of symptoms can vary, depending on the area of the bite: 

• Spider bite on dog belly: If it is a case of a spider bite on dog belly, you may notice redness in the area or small red bumps on the skin.
• Spider bite on dog’s paw: May generally go unnoticed. However, if a small spider crawls between the paws and bites, there may be some localized sensitivity. A spider bite on dog’s paw may lead to some pain and reluctance to put weight on the affected leg, for a day or so, especially in small dogs 
• Spider bite on dog’s eye: Since it is a sensitive area, a spider bite on dog’s eye will likely result in some swelling, sensitivity, and discomfort 
• Spider bite on dog’s neck: Depending on the size and thickness of fur, a spider bite on dog’s neck may go unnoticed or you may feel a small bump in the skin, some redness, and sensitivity to touch if you happen to explore the area before the effects of the bite have resolved 

It can be hard to specify the signs and symptoms of spider bite in dogs because they don’t look very different from any other insect bite and unless you’ve witnessed a spider biting your dog or a spider in your dog’s vicinity, you just can’t be sure what it is you’re dealing with. However, if you’re wondering, “How do I know if my dog has been bitten by a spider?”, keeping an eye out for the following symptoms can help: 

• Pain in the affected area
• Redness 
• Swelling 
• Irritation 
• A puncture mark
• Repeated licking of the affected area

How to Recognize a Venomous Spider Bite in Dogs

While mostly spider bite in dogs are not a cause for concern, the severity of the situation can change pretty drastically pretty quickly if certain dangerously venomous spiders bite a dog. The two that you classify as an emergency are brown recluse and black widow spider bite on dogs.

Here’s what you need to know: 

Black widow spider bite on dogs

Black widow spiders are found in several parts of the world, especially North America, South America, South Asia, Southeast Asia, and East Asia. They tend to live in dark, secluded areas and build their web between debris or undisturbed areas of the ground. A dog may get bitten by coming in contact with these webs, as the black widow typically stays close to it.  

The real risk is posed by female black widow spider bite on dogs since they are bigger and can easily puncture the dog’s skin — which the comparatively smaller males cannot. The bite leaves two puncture marks and is extremely painful. The symptoms of a black widow spider bite on dog can start within 30 minutes and worse over the next few hours. These include: 

• Extreme pain that may leave your dog crying or whining 
• Tremors and severe muscle spasms 
• Stumbling 
• Seizures 
• Stomach cramps 
• Drooling, vomiting, or diarrhea 
• Elevated heart rate and blood pressure 
• Paralysis 
• Death 

The black widow venom is a neurotoxin and is believed to be deadlier than that of a rattlesnake. However, since the quantity is a lot smaller, a bite may not always prove fatal. The severity of the symptoms depends on a variety of factors such as: 

• Size of the spider 
• Size of the dog 
• Dog’s age (symptoms can be more severe in puppies and older dogs) 
• Location of the bite 
• Certain underlying/pre-existing conditions can exacerbate the effect of the venom

The brown widow and red widow are other venomous spiders that can cause symptoms similar to the black widow spider bite on dogs. However, the severity is much less. 

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Brown recluse bite on dog 

Another equally concerning situation is if a brown recluse spider bites a dog. This venomous spider variety is native to North America and most commonly found in Midwestern and southern parts of the US. These small spiders prefer to seek shelter in covered areas such as beneath rocks and can also find their into closets, shoes, and even your dog’s bed. 

So, the risk of a bite cannot be eliminated altogether. A brown recluse spider bites only if there is counter-pressure. This means something needs to be pressing against them for their fangs to pierce the skin. The most likely scenario of a brown recluse spider bite in dogs is if your pet sits on one. This spider’s venom contains enzymes that kill surrounding tissue. As a result, the bite may not be very painful at first but can prove dangerous in the absence of timely and correct treatment. 

The venom begins to kill the tissue surrounding it almost instantaneously and the effect becomes evident anywhere between 2 to 8 hours. The site of the bite has a bull’s eye pattern and the area surrounding it begins to turn white, then purple, and eventually, turns black. Without medical attention, the depth and area of the dead tissue keep expanding.

If not detected before the toxins reach the bloodstream, it can lead to organ failure. Apart from a change in the color of the skin or affected area, symptoms of a brown recluse bite in dogs include, 

• Fever 
• Lethargy
• Weakness 
• Vomiting 
• Red or brown urine 
• Increased bruising on the skin 
• Kidney and liver damage 

You may notice similar symptoms if a Chilean Recluse spider bites a dog. 

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Spider Bite Treatment for Dogs

If a spider bites a dog, or you suspect so, immediate veterinary care is a must. A vet will identify, examine, monitor, assess, and your pet. The course of treatment depends on the severity of spider bites. In the case of a non-venomous spider bite, no treatment may be necessary. Your vet may ask you to observe your dog closely for the next few hours. Cleaning the area with soap and water can be helpful. For a swollen spider bite on dog, you apply an ice pack to help alleviate the discomfort. In such cases, you won’t have to worry about your dog recovering from spider bite.  

A venomous spider bite on a dog, however, is a different story altogether. It can lead to canine envenomation and the course of treatment will depend on the symptoms, which can tell your doctor what kind of venom you’re dealing with. 

Treatment for black widow spider bite in dogs

If the signs of a spider bite in your dog indicate a black widow as the culprit, your vet will run blood tests to look for an elevation of an enzyme called creatine kinase. This enzyme indicates muscle damage caused by the venom. The treatment options focus on alleviating the symptoms and can include: 

• IV fluids
• Muscle relaxers
• Medication to manage pain, vomiting, and seizures 
• Medications to combat seizures, and anti-nausea medication

Administering an antivenom is an option but it is also known to trigger a severe anaphylactic reaction in some dogs. That’s why, it is used in the most severe cases. 

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Treatment for brown recluse spider bite in dogs

If your pet exhibits any of the symptoms associated with a brown recluse spider bite, immediate medical attention is critical for their survival and recovery. The treatment process begins with blood tests to detect anemia, clotting abnormalities, or organ failure. The course of treatment includes: 

• A drug called Dapsone to reduce tissue death
• Antibiotics 
• Pain medication 
• Treating the bite wound 

In severe cases, a dog may require surgery or blood transfusion. Healing and recovering from spider bite can take up to eight weeks.

Preventing Spider Bites in Dogs

Seeing as how dangerous an innocuous, often hard-to-nice, spider bite can be and how hard recovering from spider bite, especially certain venomous varieties, can be on your pet’s body, prevention really is better than cure. The best you can do to prevent spider bites is: 

• Remove spider-friendly habitats from in and around your house 
• Clean out dark or lesser-used areas of your home frequently 
• Keep dog’s bedding clean  
• Don’t let your dog wander off to the nooks and corners of your yard 
• When outdoors, don’t let your dog wander off to inspect piles of wood, stone mounds, or any area that could be a spider habitat 
• If you live in an area that has a high incidence of spiders, especially the dangerous kinds, you can consider using glue traps or insecticides to rid your home of them. However, make sure that your dog does not come in contact with either of these, as they can be harmful to our canine companions 

Spiders are shy creatures and are inclined to hide from your pet (and you). However, the possibility of a spider biting your dog cannot be ruled out completely. Therefore, it is best to be informed and prepared. Whether it is a simple red bump on your pet’s skin, a swollen spider bite on dog, or signs of a venomous spider bite, I hope you will now be prepared to handle it the right way.