Bug Bites and Stings on Dogs

It's not uncommon for a dog to be bitten or stung at least once during its lifetime by some type of insect, spider, or another pest. Some are accidental one-time encounters, such as a dog that gulps down a bee and suffers a sting on its muzzle. Others are ongoing infestations, such as dogs with fleas or ticks.

Although many bites and stings are not serious and will heal on their own, some can cause pain or itching to your dog, and others, such as bites from venomous spiders, can be fatal without treatment. That's why it's important for every dog owner to recognize common signs of a bite or sting, which can include reddened bumps on the dog's skin, swelling, itchiness, scratching, or licking the affected area. Serious signs of a bite from a venomous creature might include drooling, stumbling or uncoordinated movements, tissue death around the bite, or severe swelling of the affected body part.

Any dog might suffer a bite or sting, but your dog is likeliest to encounter stinging or biting pests outside, particularly in wooded or grassy areas. You might actually see your canine's encounter with the culprit, or you might simply discover signs of the injury after the fact. Here's what you should know about common types of bites or stings on dogs.

What Are Bug Bites and Stings?

There are numerous species of insects, spiders, and other creepy crawlers capable of delivering a bite or a sting to a dog or other animal. While the end result of a bite or a sting is often the same—an itchy or painful bump—stings and bites are not the same thing. A bite involves the culprit using its mouth to break the skin of its victim, while a sting involves the use of some other body part, often a barbed stinger, to pierce the skin and deliver some type of venom.

Symptoms of Bug Bites and Stings on Dogs

The range of possible symptoms after your dog has suffered a bite or a sting is a large one. Fortunately, most are annoying but mild, such as the itch of a flea bite. However, some can be life-threatening, particularly if your dog has an allergy to bee-sting venom, which can cause anaphylactic shock.

The most common symptoms of an uncomplicated bite or sting on a dog is an itchy bump on the skin, which will usually be red or pink. The skin surrounding the bite may be red as well, particularly if the dog is scratching it excessively. You might also notice your dog licking or rubbing at the affected area.

If your dog has an flea infestation, there will typically be multiple bites over the dog's body, but especially in areas with little fur or thinner fur, such as the head, neck, inner legs, belly, tail base, and groin. A tangle with an ant hill can also result in multiple bites. Most other pests will only deliver a single bite, however.

While uncommon, there are times that a bite or sting can be very serious. If your dog has an allergy to bee stings or is bitten by a venomous spider, the symptoms will be more frightening and severe. If your dog appears shaky or weak after a bite, vomits or develops diarrhea, is struggling to breathe or has a very swollen muzzle, or develops a large sore at the site of the bite, an emergency call to your veterinarian is in order. Severe responses to insect bites or stings, called anaphylaxis, usually appear within 10 minutes of the event.

Causes of Bug Bites and Stings

Other than flea infestations, most types of bites or stings are caused by a one-time encounter with the culprit. Many dogs like to chase or even try to eat insects, which can result in a painful sting or bite on the dog's muzzle or even inside its mouth. Usually, your dog will be bitten or stung while outdoors, but occasionally a spider, ant, or another pest might bite your dog while inside your home.

While there are numerous types of insects and spiders that can bite or sting, the following are some of the most common your dog is likely to encounter.

Fleas

Fleas are among the most common type of insects that bite dogs, and one of the few that infest your dog, rather than delivering a single bite in self-defense. Some dogs seem unaffected by flea bites, but many are allergic and will experience extreme itching and irritation of the skin. Dogs with severe flea allergies may experience itching all over after just one or two flea bites. These dogs can develop secondary skin infections due to the inflamed, broken skin at the site of the bites.

Flea bites may look like tiny, raised red bumps, or may simply cause a diffuse area of redness on the skin. Dogs with flea infestations often have black spots on the skin from flea feces. You'll usually see the fleas as well, especially on the dog's inner thighs, groin, or belly where the fur is thin.

Ticks

Tick bites are common in dogs, especially dogs that accompany their owners on hikes or camping trips. These eight-legged parasites are generally encountered in outdoor areas with a lot of weeds, tall grass, or fallen leaves. When ticks bite dogs, they attach to the skin and feed on the blood until they are full. The most common spots for a tick bite are the dog's legs, flanks, face, ears, and head.

You can easily recognize a tick bite when the tick is still attached. Ticks will grow significantly while feeding and may look like a wart or other skin growth on the dog. If the tick has already fallen off the dog, you may notice a small red bump. This bump typically disappears after a few days and usually doesn't bother the dog unless the area becomes infected. Signs of tick-borne diseases may appear days, weeks, or months after being bitten.

Ants

Ant bites usually occur after a dog mistakenly steps on an anthill or tries to eat ants. Bites can occur anywhere on a dog's body, but the feet and mouth are more common.

There are many species of ants, so the effects of their bites will vary. Most ant bites cause mild to moderate pain, swelling, and redness at the site of the bite. The bite may itch while it heals, but serious allergic reactions are uncommon. Fire ants are an exception to this; their venom can cause intense pain and serious allergic reaction including facial swelling and anaphylaxis.

Bees, Wasps, and Hornets

It's not uncommon for dogs to be stung by bees, hornets, or wasps. Many dogs are curious about flying insects and will chase them and try to eat them. Stings in the mouth and on the face are common. Dogs that disturb nests and hives may get stung multiple times on the body.

Stings from bees, wasps, and hornets are painful and become red and swollen. You may notice your dog yelp and suddenly pay attention to an area on its body. It may try to lick, chew, or paw at the site of the sting. Some dogs experience serious allergic reactions to bees, especially if stung in the mouth. This can cause facial swelling and anaphylaxis.

Flies

Fly bites are relatively common in some regions. There are a few types of flies that are known to bite dogs and feed on their blood. Bites from black flies and horse flies are among the most common flies that bite dogs.

Fly bites can leave red blotches on the skin that are round or oval in shape. They may resemble hives or welts. Fly bites can occur anywhere on the body, but they are especially common on the face and ears. Fly bites rarely cause serious allergic reactions in dogs, but they may be painful and itchy for a few days. Outdoor dogs may experience frequent fly bites that cause crusty lesions, especially on the ears. These can become infected without treatment.

Spiders

Spiders are most likely to bite dogs when they are threatened. A spider bite may occur if your dog tries to catch a spider and eat it. However, spider bites can easily happen while your dog is at rest. The most threatening bites come from black widow and brown recluse spiders.

Most spiders are venomous, but their bites are usually not severe enough to have serious effects on dogs. The appearance of a spider bite depends on the species of the spider.

Brown recluse spider bites are painless, so your dog may will not immediately react to a bite. Within a few hours, however, the site of the bite may look like a blister. This progresses to a red target lesion that looks like a bull's eye. The skin around the bite may first become pale and then turn dark as the tissue dies due to the venom. Systemic effects are uncommon but may include lethargy, vomiting, fever, and weakness due to the venom's effect on the blood cells.

Black widow spider venom contains a neurotoxin called a-latrotoxin. These bites cause mild to moderate pain followed by redness. Systemic signs include muscle pain, drooling, vomiting, diarrhea, drunkenness, tremors, and paralysis. Black widow bites can be fatal to dogs and require immediate medical attention.

Scorpions

Scorpion stings are seen in dogs in certain areas of the world, most often in the southwest region of the US. Most scorpion species in the US contain non-harmful venom. However, the Arizona bark scorpion contains dangerous venom that causes systemic effects. Scorpions are usually reclusive, so a sting from one means your dog probably came too close to an area where one was hiding. A dog may be stung in the mouth or on the face after trying to eat a scorpion.

Scorpion stings are very painful. You may hear your dog yelp and begin to bother the affected area. The site of the sting may become red and swollen and your dog may begin drooling. Stings from the Arizona bark scorpion can cause dilated pupils, drunkenness, tremors, walking drunk, and abnormal eye movement. Contact your veterinarian right away if your dog has been stung by a scorpion.

Diagnosing Bug Bites and Stings on Dogs

Often, you'll see your dog be bitten or stung, or you'll observe fleas or ticks on your dog, making the diagnosis simple. Other times, you'll discover a red or pink bump, or multiple bumps, on your dog when seeking the cause of your dog's incessant scratching.

While most bites and stings don't require a trip to the veterinarian, if your dog has a severe reaction or anaphylactic shock, which can include difficulty breathing, vomiting, weakness, shaking, or collapse, an emergency trip to the vet is a must. Your veterinarian will examine your dog, paying particular attention to any bumps or other inflamed areas. A diagnosis can often be made based on the dog's symptoms and clinical condition along with your description of events just prior to the start of the symptoms.

Occasionally, your vet may decide to run blood work to look for indications of systemic symptoms, such as an increase in a certain type of white blood cell that can mean your dog is having an allergic response to something, such as a bee sting.

Treatment

Minor bites and stings can often be treated at home, but your vet should help you determine the best course of action if you are uncertain as to what to do or if your dog shows severe or persistent symptoms.

Home treatment involves removing the stinger if present. Use the edge of a credit card or other rigid item to scrape away the stinger; don't use tweezers, which can squeeze out more venom.

Clean the affected area with a gentle soap and then pat it dry. You may apply ice to the site of the sting to reduce swelling, pain, and itching. Other options are oatmeal baths or a thick paste of water and baking soda applied to the inflamed spot. If your dog is damaging its skin with incessant scratching, an Elizabethan collar might be required until the itch abates.

If your vet approves, you can administer oral diphenhydramine, which is available over-the-counter. Follow your veterinarian's directions for dosage and frequency.

Bring your dog to the nearest open veterinary facility after a bite or sting that causes intense pain, facial swelling, trouble breathing, or other signs of illness. Emergency treatment may be necessary and will depend on the type of bite or sting as well as the type of reaction experienced by the dog. Antivenin is rarely used, but supportive care may be needed. Potential treatment includes antihistamines, steroids, antibiotics, pain medications, and fluid therapy.

If your dog's bites are from fleas, the infestation needs to be treated with an anti-flea medication before healing can begin. You may then choose to regularly apply a preventative medication, such as Frontline Plus, that kills fleas or ticks that bite your dog.

Prognosis for Dogs With Bug Bites or Stings

The vast majority of bug bites or stings heal on their own within a few days and don't affect your dog's health beyond the itch and annoyance. However, a dog that suffers anaphylactic shock to a bee sting or ant bite, or a dog that's bitten by a venomous spider, may have a poor outcome if veterinary attention isn't sought out right away for treatment.

How to Prevent Bug Bites and Stings

While you can't entirely prevent a bug bite or sting, there are ways to prevent some of them from happening to your dog. Use an effective monthly flea control product to prevent flea infestation. Tick control products are also available if you live in a region known for these parasites. Fly repellent can help keep flying insects at bay. Ask your vet about the best products for your dog.

Be sure to keep your dog away from beehives and nests of wasps and hornets, as well as ant hills. Seek professional help if necessary to remove these pests your property so you can keep pets and people safe. Supervise your dog and do your best to stop it from trying to catch or eat insects.