Did you know that there are over 3,000 species of spiders in the United States and over 45,000 in the world?1 Despite these facts, it should be of great consolation to know that only a very small handful pose a real medical threat to your dog. In the United States, the two groups of spiders that can cause envenomation with clinical signs would be Widow Spiders (Latrodectus species) and Brown Recluse Spiders (Loxosceles species).
But, aside from this small subset of spider species’ bites, or a rare reaction from any bite, most dogs will not need veterinary care from a spider bite. So how do you treat spider bites on dogs? Well, let’s find out more below!
Most Spiders Bite
While most spiders are actually venomous, there are various reasons why they do not cause problems if they happen to bite your dog—such as too small of mouthparts to get the venom into the skin or the amount/potency of the toxin is not worrisome to your pup. This does not mean that your dog could not have a possible rare allergic reaction or get a secondary infection due to a bite, but most of the time, spider bites are not very painful and unless clinical signs appear, they often are not a problem. They may have some mild local swelling and redness, but many dogs won’t even give them a first (or second) thought.
In addition, in veterinary medicine, we often do not have the luxury of seeing an actual spider bite our pet in the moment and furthermore, we can’t talk to our dog to find out more information! It could be reasonably deduced that spider bites are a) difficult to diagnose and b) difficult to recognize except in instances where an owner sees the occurrence firsthand. We often may suspect a spider or bug bite due to evidence and signs after the fact. Furthermore, sometimes what one suspects is a spider bite, may actually have a different cause, that may need to be investigated by a veterinarian if it continues.
How to Treat a Spider Bite on Dogs
If you see or have evidence of a spider start with step one. If you don’t see one but suspect a possible spider bite, skip ahead to step four.
1. Keep calm and breathe
Even if you’re afraid of spiders, your dog can feed off your energy and needs you at your best to benefit from your care.
2. If you actually see the spider
Try to safely collect it in a jar or a sealed cup that you can hold onto for identification purposes. If you can’t collect it, pictures or videos may also prove to be helpful.
3. Identify the spider
Helpful sources for this could be through books, websites, identification apps, contact with those who study insects (entomologists) or spiders (arachnologists), etc.
4. Monitor your pet now
In the coming hours, and over the next few days, and be on the lookout for any changes. You know your dog best and noting differences in your pet’s appearance or behavior will be helpful in determining if things are progressing.
5. For a typical bite
You can expect to see some minor irritation at the area affected, such as a small bump with mild symptoms including a little swelling, itching, or redness. Anything more severe than this should warrant medical attention. Systemic signs such as fever, vomiting, or lethargy are not normal and should be investigated.
6. Signs of a reaction
(Allergy or infection) or additional medical problems arise now or going forward, this would be an emergency. This could include signs such as facial swelling, trouble breathing, continual vomiting, signs of lethargy, or intense swelling/redness/pus that form at the site in question. Again, these are rare occurrences, but something to watch out for.
7. If your dog permits
Wash the area with mild soap and water.
8. A mild cold compress
A mild cold compress may help bring some topical relief.
9. Contact your veterinarian and explain the situation
Remember that they have your dog’s best interest at heart! They may want to see your pet or give you advice on when to bring your pet in. In some circumstances, they could give some general advice for mild situations, such as an antihistamine dose based on your pet’s weight or instructions for a topical chlorhexidine/antimicrobial product.
10. Discourage your pet from licking or scratching the area
These can actually cause or make an infection more likely. An Elizabethan collar (often called “the cone of shame”) can be very helpful to keep your dog from accessing the area if it is becoming a problem.
11. Prevent possible future spider bites
While it is possible for a spider to be almost anywhere, spider prevention inside and outside your home (as long as it is also pet friendly), may help you and your pet have some peace of mind.
Worrisome Spider Bites
It should be noted that if you see or suspect these spider bites, contact your veterinarian right away. Alternatively, if you start to see some of the signs discussed below, a spider bite from a worrisome species may be on the list of possibilities.
1. Widow Spiders
Latrodectus mactans, or Black Widow Spiders are the most common species in this group, but there are also others. A Black Widow typically is 2–2.5 cm long and has a black shiny body with a red to orange hourglass mark on the underside of their abdomen. The immature female may be brown with red to orange stripes that will change to the more typical colors and markings as they age. A bite can have venom or be dry (no venom injected); but you may not know which type the bite is until after, when signs are detected.
These spiders are often found where humans may live in all the states within the US except Alaska. Their venom is a potent neurotoxin that can be painful and cause long-acting muscle spasms and cramping. Additional signs that can be seen include anxiety and restlessness, excess salivation, facial swelling, irregular breathing, a hard or painful abdomen, weakness, partial paralysis, or going into shock.
In cases where there is confirmation or a suspected bite, there is an antivenom that may be potentially used, but it may not always be available or an option. Symptomatic treatment is also sometimes all that may be needed for dogs and can entail intravenous (IV) medication to help with the pain and muscle relaxation as well as possible IV fluids. There will be monitoring of the wound until it is healed, and it is important to note that weakness or partial paralysis may continue for several days during recovery.
2. Brown Recluse Spiders
L. reclusa is the most common Brown Recluse Spider and its envenomation is typical for the—at a minimum—10 species in this group in the United States. These spiders are 8–15mm in size with legs that are 2–3 cm long and they most often have a violin-shaped pattern on their back. They can be found throughout much of the United States with various species in different geographical areas.
A bite will often have a red, large skin lesion that develops a “bulls-eye” appearance and sometimes can develop into an ulcer that gets larger without medical intervention. The venom affects blood vessels as well as blood cells and clotting factors around the lesion. Systemic signs can also take place within a few days after the bite, such as fever, rash, nausea or vomiting, and weakness. Renal failure and shock may also occur, and sometimes in severe cases, damage to the red blood cells, platelets, and clotting factors can be diffuse throughout the body.
Unfortunately, there is no antivenom for these bites, but wound and supportive care would be indicated. This can include promptly applying a cool compress to the affected area as well as IV fluids. Additional treatment such as antibiotics to prevent a secondary infection, steroids, and oxygen may be warranted. Dapsone, a medication used in people for leprosy, may also be an option to decrease inflammation, although its efficacy has not readily been studied in dogs. The wound may need to have damaged tissue removed (debrided) and in severe cases, skin grafting may be needed.
Spiders and their bites, while scary to some, typically aren’t something to be too concerned about for your canine friend. In the less common circumstance that your dog is having a reaction to a bite (allergic or infection), you see/suspect one of the concerning spider species as discussed, or there are more worrisome medical signs in your dog, your veterinarian is only a call away!
Featured Image Credit: kenkuza, Shutterstock