What Happens When Dogs Get Bitten by Spiders?
Dogs love to sniff around in places where spiders like to hang out, so they’re often at risk of getting bitten. Most spider bites are relatively harmless, but some spiders can pose a real danger to your dog’s health.
That’s why it’s important to know what to look for. Recognizing the signs of a spider bite and getting your dog to the vet quickly can make a big difference in their recovery. The sooner you identify and treat the bite, the better your dog’s chances of a good outcome.
This guide will walk you through the common types of spiders that bite dogs, the specific symptoms of those bites, available treatments, and how to help prevent future bites.
Common spider species of concern to dog owners
While most spider bites are harmless, some spiders pack a venomous punch that can make your dog sick. Here are a few to be aware of:
Black widow spiders
These spiders are easy to spot because of their shiny black bodies and the red hourglass shape on their undersides. They live throughout North America, but they’re more common in warmer climates.
Black widow venom is a powerful neurotoxin. According to The Merck Veterinary Manual, black widow spiders’ mouthparts are big enough to penetrate the skin and deliver enough venom to cause severe harm. Black widow venom is thought to be 15 times more potent than rattlesnake venom, but typically, less of it is injected into the victim.
Brown recluse spiders
Brown recluse spiders are brown and have a violin-shaped marking on their backs. They prefer dark and quiet spots like closets, garages, and woodpiles.
Brown recluse venom contains sphingomyelinase D, a substance that interferes with blood clotting and causes the tissue around the bite to die, or become necrotic. Like black widows, brown recluse spiders have mouthparts large enough to penetrate the skin and deliver sufficient quantities of venom to cause severe harm, according to The Merck Veterinary Manual.
Other widow spiders
There are a few other types of widow spiders that pet owners should be aware of:
- Red widow spiders: Red widows are mainly found in Florida. Their venom is similar to that of black widows, but because they’re smaller, their bites tend to be less severe.
- Brown widow spiders: Brown widows are becoming more common in urban areas. Their venom is similar to black widows’, but their bites are often less severe.
These spiders aren’t as likely to cause serious problems in dogs, but it’s still a good idea to be aware of them.
Symptoms of Spider Bites in Dogs
Most of the time, a spider bite is just a minor nuisance for your dog. But in some cases, a bite can cause serious symptoms and require immediate veterinary care. Here’s what to watch out for.
General Symptoms
With most spider bites, your dog will have a localized reaction, meaning the symptoms are limited to the area of the bite. These symptoms can include:
- Localized pain
- Redness
- Swelling
- Itching
Often, these symptoms are mild and will go away without treatment. But more severe bites can cause systemic symptoms, meaning they affect the whole body. These symptoms include:
- Fever
- Lethargy
- Vomiting
- Difficulty breathing
If your dog has any of these symptoms, it’s important to seek veterinary attention right away.
Black Widow Bite Symptoms
A bite from a black widow spider can be quite serious for dogs. Although some dogs don’t seem to react much at first, symptoms can appear within 30 minutes and worsen over the next 8 hours.
Symptoms of a black widow bite can include:
- Muscle pain, stiffness, and spasms
- Tremors
- Paralysis
- Difficulty breathing
- Seizures (in severe cases)
- Coma (in severe cases)
Brown Recluse Bite Symptoms
A bite from a brown recluse spider can also be quite serious. The initial bite may be painless, and symptoms can take anywhere from 2 to 8 hours to show up.
Symptoms of a brown recluse bite can include:
- A moderately painful bite
- A “bull’s-eye” lesion with a red ring around a pale center
- Tissue necrosis (death), which can lead to a deep, open sore
- Fever
- Chills
- Nausea
- Vomiting
- Kidney damage (in rare cases)
- Blood clotting disorders (in rare cases)
How do vets diagnose spider bites in dogs?
Diagnosing a spider bite on a dog can be tricky. Vets rely on several factors to make an accurate assessment:
- Physical Examination: Your vet will start with a thorough examination, paying close attention to the bite site and your dog’s overall condition.
- History: Be ready to share as much as you can about your dog’s recent activities. Where has your dog been? When did you first notice symptoms? Any detail could help.
- Spider Identification: If you happen to see the spider, try to safely capture it or take a picture. Identifying the spider can make a huge difference in choosing the right treatment.
- Ruling Out Other Problems: It’s important to remember that other issues can mimic spider bites, like insect stings, skin infections, or allergic reactions. Your vet will want to rule those out to be sure.
Treatment of spider bites in dogs
How a spider bite is treated depends on the type of spider, the severity of the bite, and your dog’s reaction to the venom. Here’s an overview of typical treatments.
General treatment
For most spider bites, the approach is to clean the wound and treat the symptoms.
- Wound care: Gently wash the bite area with a mild soap and water. Apply a cold compress to reduce swelling and relieve pain.
- Pain management: Your veterinarian may prescribe a pain medication to keep your dog comfortable.
- Antihistamines: Antihistamines can help reduce itching and inflammation at the bite site.
Black widow bite treatment
Black widow venom is neurotoxic, meaning it affects the nervous system. If you suspect your dog has been bitten by a black widow, seek immediate veterinary care.
- Antivenom: An antivenom is available for black widow bites, and it can be very effective if given soon after the bite. However, not every veterinarian carries antivenom, so you or your vet may need to call around to locate some.
- Supportive care: Muscle relaxants can help alleviate the muscle spasms caused by the venom. IV fluids may be needed to keep your dog hydrated and maintain electrolyte balance.
Brown recluse bite treatment
Brown recluse venom is cytotoxic, meaning it destroys cells and tissues. Brown recluse bites can cause a severe local reaction. Quick veterinary intervention is essential.
- Wound management: It’s important to keep the wound clean and bandaged to prevent a secondary infection. In severe cases, surgical debridement (removal of dead tissue) may be needed.
- Supportive care: Unfortunately, there’s no antivenom available for brown recluse bites in dogs. Treatment focuses on managing the symptoms and preventing complications. Your vet may prescribe antibiotics to treat any secondary infections that develop.
How to protect your dog from spider bites
The best way to keep your dog safe from spider bites is to take steps to reduce the spider population in your house and yard and limit your dog’s exposure to spiders.
Here are some tips:
- Eliminate spider habitats: Clear away clutter and debris around your house and yard. Seal any cracks and crevices in your walls and foundation. Regularly clean out areas where spiders like to hide, such as basements, garages, and sheds.
- Pest control: Use non-toxic insecticides or traps to control the spider population in and around your home. You may also want to consider professional pest control services, especially if you have a large spider population or are dealing with venomous spiders.
- Supervise your dog: Keep your dog away from dark, secluded areas where spiders may live. Don’t leave your dog unattended in areas with potential spider habitats, such as woodpiles, sheds, or garages.
- Maintain cleanliness: Regularly clean your dog’s bedding and living areas to remove potential hiding places for spiders.
- Be aware: Learn to identify common spider species in your area, especially venomous ones. This will help you take appropriate precautions and seek veterinary care promptly if your dog is bitten.
Final Thoughts
Spider bites are something most dog owners don’t think about until their beloved pet is in distress. It’s important to know that certain spider bites, particularly those from black widows and brown recluses, can be dangerous for dogs. Recognizing the symptoms early and getting your dog to the vet quickly is key to a good outcome.
The good news is that you can take steps to keep your dog safer from spider bites. Eliminating spider habitats around your home and being mindful of where your dog is sniffing and exploring outdoors can significantly reduce the risk.
Although spider bites can be worrisome, most aren’t life-threatening. By being informed and taking proactive steps, you can minimize the risk to your canine companion and ensure their continued health and happiness.