Bug bites are not fun for humans or their furry friends. Typically, itchy mosquito bites or spider bites cause just some discomfort. However, some species of spiders can cause more severe reactions when they bite, particularly in small dogs or pets with allergies.
Knowing the tell-tale signs of a spider bite on dogs can help pet parents seek prompt medical advice, increasing the likelihood of successful treatment and healing.
Most spider bites on dogs are not dangerous at all. Still, it’s a good idea to be aware of them so that you can monitor your dog and seek medical treatment if your pet is experiencing serious side effects.
Notably, two species of spiders, the black widow and recluse, produce enough venom to trigger problems like diarrhea, rapid heart rate, tremors, and, rarely, kidney failure (Trusted Source).
Besides the type of spider that bit a dog, many factors play into which dogs are at the highest risk for more severe outcomes. A dog’s size, age, and the size of the bite may all affect the need for treatment. Monitoring your pet for irregular behavior that could be spider bite symptoms and seeking emergency care can reduce the harm caused by spider bites.
It’s challenging to identify and diagnose a spider bite definitively. The only way to accurately diagnose a spider bite is to find the precise spider that bit the dog — a tall feat, as you can likely imagine. Instead, a vet will usually base a diagnosis on clinical signs in an animal, such as:
Sometimes, a blood test can diagnose black widow spider bites. In rare cases, a dog may experience severe symptoms, including seizures, paralysis, kidney failure, or death.
When a more dangerous spider like a black widow or brown recluse penetrates a dog’s skin with enough venom, it can cause or trigger some of the most severe symptoms.
Spider venom comes from specialized secretory cells in what’s known as the venom gland (Trusted Source). When enough venom is injected, a dog may experience various clinical signs ranging from mild to life-threatening. This venom causes symptoms to develop, including swelling on and around the affected area, tissue damage, fever, breathing problems, high blood pressure, kidney dysfunction, and even death.
Though death only happens in the most severe cases — even from black widow or brown recluse spider bites — prompt medical care from a team of veterinary experts is the best way to improve your dog’s prognosis.
Non-venomous spider bites (usually) can be treated at home so long as there’s no sign of infection. However, there are some caveats. You’ll want to call the vet ASAP if you notice a black widow or brown recluse bite, as those are dangerous but not typically fatal with prompt veterinarian treatment.
👉 If the affected area doesn’t seem to be improving after several days, call your vet.
Your veterinarian is the best resource for how to treat a brown recluse bite on a dog — ditto for a black widow bite (or any spider bite). Treatment options will vary depending on the type of spider that bit your dog.
Black widow bites can be treated with a medicine known as antivenin (Trusted Source) or antivenom. The medication is injectable and must be given while the dog is in the hospital for the bite. It can cause severe reactions in some dogs, so this route is usually reserved for the most severe spider bite cases. Pain relief medication, IV fluids, and muscle relaxers are other treatments that may help. Your pet may need to be hospitalized for two to three days following a black widow spider bite, and it can take weeks or months to heal completely.
Brown recluse spider bites mostly require monitoring — there’s no antivenin as these bites are very rarely fatal. Treatments to manage symptoms include antibiotics, pain relief, and treatment of the affected area. In the most serious cases, a dog may need blood transfusions or surgical treatment. It can take up to two months for a pup to fully recover.
It’s challenging to know whether a spider has bitten a dog unless the exact insect is found and tested. Vets typically use clinical signs to diagnose a bite. Redness, itchiness, and small red bumps are common signs of spider bites on dogs. A dog may develop a fever, become lethargic, and even experience seizures in more severe cases.
It depends on the severity. A dog spider bite may include at-home treatments like cleaning the affected area with soap and water and applying a cold compress. The most severe venomous spider bites may require pain medication, antivenom, IV fluids, blood transfusions, and surgical treatment.
Rarely. Spider bites are usually harmless to dogs, though they may cause discomfort, such as itchiness. If a black widow or brown recluse spider bites your dog and injects enough venom, they may experience more serious symptoms like a fever, lethargy, tissue damage, and kidney failure. Call your vet if your dog is experiencing severe symptoms or if you believe they were the victim of a black widow or brown recluse spider bite.
Brown recluse and black widow spiders are the two types of venomous spiders considered most dangerous to dogs. Unlike other spiders, these two species are able to inject enough venom into a dog’s skin, causing more severe symptoms and warranting prompt medical care.
Keep your home and yard free of spider webs. Spiders like to hide in wood or leaf piles, so minimizing those in your home and yard is also helpful. Try to keep a safe distance from spider webs when out and about with your pup. Your vet may be able to recommend dog-safe insect repellents.
