7 Common Bug Bites on Dogs

Updated Sep. 12, 2023
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Dogs can be bitten and stung by a variety of insects, so it’s important to know what the different insect bites look like on a dog. Not all insect bites need to be treated, but certain symptoms require immediate medical attention. Knowing how to protect your dog from these insects is also key to keeping your pet healthy.

Fleas

Fleas are tiny, dark brown insects that jump on a dog to feed on its blood. They are often carried in from outdoors, and once inside the house, they breed and multiply. Dogs will chew and scratch at their bodies when they are bitten by fleas due to the painful bite. The scratching and chewing can lead to self-trauma of the skin that causes scratches and sores to form. The bite of a flea can be difficult to see under a dog’s thick coat. Flea bites look like small, red spots on the skin, but sometimes it can be hard to tell their bite from the bite of another insect.

If you see insect bites on your pup, or notice that your dog is chewing and scratching a lot, the first thing to look for are flea dirt and live fleas. Flea dirt consists of fecal material and dried blood and looks like tiny, black flecks on the skin. Fleas and flea dirt are most often found on the lower back, tail, and on the hind legs of dogs.

Some dogs have an allergy to flea saliva, and one flea bite can lead to flea bite dermatitis. This skin condition causes intense itchiness all over, hair loss, and sores due to self-trauma. Bacterial and yeast infections can develop secondary to a flea allergy.

The best way to prevent and treat fleas is with flea and tick prevention. There are many types of flea and tick preventions available, such as topical products, flea/tick collars, and oral medication. Talk with your local veterinarian to decide which flea and tick product is best for your dog, and make sure to administer it year-round to keep the fleas and ticks away.

Ticks

Ticks are eight-legged parasites that like to hide in the grass, shrubs or woods. When a dog walks by they will crawl onto the dog’s body, usually on the legs or paws first before burrowing into the skin. They will then bite to suck blood from their new host.

A tick bite looks like a circular area of inflamed skin. The area is often red and slightly swollen after a tick is removed or falls off and crusts or a scab may also be present. The skin lesion may be itchy and irritating to your dog. As a natural reaction, dogs may want to scratch or lick at a tick bite after the tick is gone, and that causes the area to become infected. Occasionally, when a tick transmits Lyme disease, the tick bite looks like a red bullseye lesion on the skin. If you remove any ticks from your dog, especially if they were already attached to the skin, contact your veterinary hospital to get your pup started on flea/tick prevention immediately. Also, schedule an appointment to bring your dog in to be tested for tick diseases within two-to-three months after the tick bite or tick was found. It’s important to screen for tick diseases and provide treatment if a tick disease is detected. 

Check dogs daily for ticks, especially after they have been in an area where ticks are present. Ticks can be found anywhere on a dog’s body but are most common on the feet, neck, head, and ears. Some ticks can be found in the webbing between the toes or attached to the anus, so looking everywhere on your dog for ticks and tick bites is important.

To protect against ticks, dogs need to be on year-round flea and tick prevention plan. There are many types of flea and tick preventatives available that are applied differently. Ask your veterinarian which flea and tick prevention are the most effective and safest for your dog.

Mites

Skin mites, such as sarcoptic mange and demodex, are so tiny they cannot be seen by the naked eye. Their bites also are not visible. However, when there are enough mites in certain areas on a dog’s body, they will cause the fur to fall out in those spots, forming patchy areas of hair loss. These areas are extremely itchy if sarcoptic mange is present. Demodex does not cause itchiness but can lead to secondary bacterial infections, which can cause the skin to be itchy, red, crusty, or have pustules.

The mite that causes sarcoptic mange (aka scabies) is called Sarcoptes scabiei, and is highly contagious. Dogs get sarcoptic mange by being in contact with a fox or another dog that has these mites on its fur. Dogs can also spread sarcoptic mange to humans. 

The two mites that cause demodex on dogs are Demodex canis and Demodex injal. These mites are normal inhabitants on a dog’s skin. However, when a dog has a compromised immune system, due to being young or having an immune-mediated condition, these demodectic mites become plentiful and cause hair loss. If your dog shows any signs of mange, contact your veterinarian to schedule an appointment.

Sarcoptic mange can be prevented by keeping dogs away from foxes and infected dogs. Also, certain flea/tick preventatives protect against demodex and scabies, such as NexGard, Simparica, and Bravecto. Giving one of these products to your dog year-round will not only protect them from fleas and ticks but also skin mites.

Another type of mite that can be a nuisance to a dog is the ear mite known as Otodectes cynotis. These mites are contagious, so keeping your dog away from dogs and cats that have these ear mites will keep your pup protected. Ear mites only live within the vertical and horizontal ear canals, so their bites are not visible.

Mosquitoes

Mosquitoes are one of the most common flying insects and are found in most places around the world. They will bite and feed on dogs when they are outside but can also make their way indoors. A mosquito bite on a dog can appear red with a raised skin lesion—just like that of a human. Mosquitoes can bite a dog anywhere on its body, but they have an easier time biting areas where there is less fur, such as the ears, belly, inner legs, and groin region.

Mosquito bites do not need to be treated unless hives develop, which indicates an allergic reaction. If your pup is having an allergic reaction, call your local vet hospital for guidance. A major concern with a mosquito bite is the risk of heartworm disease. Not all mosquitoes carry heartworm disease, but those that are infected will transmit this parasite through a bite. It is crucial for dogs to be on year-round heartworm prevention to protect against heartworm disease.

Here are a few ways to protect your dog from mosquitoes:

  • Have a pest control company come to your house and spray the yard with mosquito repellant. Find out from the company if there is a certain amount of time to keep your pets off the grass after the yard has been treated.

  • Apply a pet-safe bug repellant spray on your dog’s coat before your dog goes outside, such as Vet’s Best Natural Mosquito Repellant Spray. This product is made of natural oils and can be sprayed on the coat every two hours as needed.

  • Topical products, like Advantix II and Vectra 3D, protect against fleas, ticks, and mosquitoes. One dose lasts 30 days. These products are only labeled for dogs. Do not use on cats, as medications formulated for dogs are toxic to cats.

Bees/Hornets/Wasps

Stinging insects, including bees, hornets, yellow jackets, and wasps, can cause significant pain when they sting a dog. Dogs may cry out suddenly and lick the area where they were stung. If a dog gets stung on the paw or leg, they may start limping immediately. Most stings can cause localized swelling, pain, and redness. Applying an ice pack to the area for 5-10 minutes as needed can help provide comfort and reduce swelling. Call your veterinarian to ask if Benadryl should be given and at what dose.

Some dogs may have an allergic reaction when they are stung by a bee, hornet, wasp, or yellow jacket. Symptoms of an allergic reaction include:

  • Facial swelling

  • Hives

  • Difficulty breathing

  • Intense itchiness

  • Moderate to severe swelling at the site of the sting

Gastrointestinal symptoms including vomiting and diarrhea.

If these symptoms occur, this is a life-threatening emergency, and you need to contact your nearest veterinary hospital immediately.

Bees, wasps, hornets, and yellow jackets are prevalent during the warmer months, and they can be difficult to avoid. Their nests can be hidden from view in trees, on buildings, or under the ground. If you know there is a nest in your yard, keeping your dog away from that area will help.

Ants

Ants, especially fire ants, can cause a painful bite on a dog. The bite can look like a red, raised skin lesion and occasionally have a white center filled with pus, like a pimple. Applying an ice pack to the area can help reduce pain and swelling. If your dog was bitten by several fire ants, call your local veterinarian to ask if Benadryl should be given and at what dose.

Ant bites, most often from fire ants, can occasionally cause an allergic reaction, especially if a dog gets bitten by several ants at once. Facial swelling, hives, difficulty breathing, itchiness, moderate to severe swelling at the site of the bite, and gastrointestinal symptoms such as vomiting and diarrhea are all possible symptoms of an allergic reaction. If these symptoms occur, this is a life-threatening emergency, contact your nearest animal hospital immediately. 

It can be difficult to prevent your dog from being bitten by ants as these small insects can be hard to see in the grass and wooded areas. Check your yard regularly for ant hills and treat them, if found. Keeping your dog on a leash when walking or hiking can help guide your dog around an ant hill if you come across one. If you find ants on your dog’s body, brush them off as quickly as possible or rinse them off with water, if available.

Biting Flies

There are many biting flies that can leave a painful bite on a dog’s body, such as horse flies, deer flies, black flies, and sand flies. The bite can look like a red, raised lesion on the skin. Applying an ice pack to the area can help to reduce pain and swelling.

Some dogs are allergic to these flies and can have an allergic reaction when bitten. Facial swelling, hives, difficulty breathing, itchiness, moderate-to-severe swelling at the site of the bite, and gastrointestinal symptoms including vomiting and diarrhea are indications of an allergic reaction. If your dog experiences any of these signs, contact your local veterinary hospital as this is considered a medical emergency.

Keep Pups Safe When Outside

Biting and stinging insects are unavoidable, as they can be found anywhere outdoors and sometimes can make their way into the home. It is crucial to have your dog on flea and tick prevention year-round. Also, consider preventatives that can protect against mosquitoes and biting flies if these insects are prevalent in your area. Heartworm prevention is also essential to give to your dog year-round protection against heartworm disease transmitted by mosquitoes.

When outside, it is best to supervise your dog and check its skin for insect bites daily. Seek immediate treatment if you notice that your dog is displaying symptoms of an allergic reaction.

Featured Image: iStock.com/mixetto

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Michelle Diener, DVM

WRITTEN BY

Michelle Diener, DVM

Veterinarian

I live in Raleigh, North Carolina. I obtained by BS degree in Biology at UNC-Chapel Hill in 2000 and my DVM degree at NCSU in 2006. I have...


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