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Preventing and Treating Mosquito Bites in Dogs

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Preventing and Treating Mosquito Bites in Dogs

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The only thing I dislike about warm months is that the mosquitoes come back in full force. If you live in an area where you don’t have them, consider yourself lucky. In my area, they are out day and night.

Mosquitoes are not only annoying to our dogs and us, but they also carry diseases. For dogs, the main disease transmitted by mosquitoes that we are concerned about is heartworm disease. When left untreated, heartworm disease can be fatal, and it’s an expensive disease to treat. It’s better and safer for your pet to prevent it in the first place.

To prevent heartworm disease, have your Chihuahua routinely screened for the disease (it’s a simple blood test). If he doesn’t have it, you can put him on heartworm preventative medicine. You can get it from your vet, your local pet store, or Chewy.

Another issue caused by mosquito bites is that your dog can scratch it until it bleeds or develops an infection. Let’s look at the dangers of mosquito bites and why preventing and treating mosquito bites in dogs is so important.


This is a parasitic condition that is very serious for dogs. The disease is spread by mosquitoes. When an infected dog is bitten, the blood the mosquito ingsts may contain heartworm offspring. So, when that same infected mosquito goes and bites another dog, that heartworm offspring passes through.

Once inside of a host, heartworm parasites can grow to be up to a foot long and can cause serious damage to the lungs, the arteries, and the heart. Other symptoms of heartworm infection in dogs include lethargy, coughing, vomiting, difficulty breathing, fainting, and exercise intolerance. Yes, all of this can happen from a single insect bite.

West Nile Virus is another disease that mosquitoes pick up and transmit to your dog. The mosquitoes get West Nile Virus from infected birds. However, an infected dog rarely develops this disease.


Testing is one of the most important aspects of heartworm treatment in dogs. The vet will perform a blood test to rule out heartworm disease before starting any kind of preventative treatment for a mosquito bite.

As always, any treatment you put your dog through should be under the direction and control of your veterinarian.

Heartworm prevention

While we do all we can as Chi owners to prevent them from being bitten by mosquitos, those little buggers are stubborn! Their small size also makes it easy for them to go undetected.

A single bite is enough to transmit disease, so it’s best to stay on top of preventative care. Medications to prevent heartworm come in topical or oral options, but there is an injectable option as well.

 The American Heartworm Society recommends year-round heartworm prevention and testing every 12 months. This is especially important in the Southern States where heartworm disease runs rampant!

Your vet will perform heartworm testing at your Chi’s annual wellness visit. Ask them which option may be best for your pup or for a prescription so you can purchase the product from a website like

Heartworm medication is well tolerated and most dogs think they’re getting a special treat. Know that it is easy to prevent this potentially fatal disease. We must do our best to keep our pups safe!


  • Wipe the area with a little rubbing alcohol. It seems to stop the itch.
  • I have also dabbed bites with coconut oil, which healed it quickly and took away the itch.
  • Haven’t tried this but have heard that Preparation H helps relieve the itch– be mindful that your dog cannot lick this product.
  • If you are growing Basil in your garden, pick off a leaf and rub the bite with it.

It is also a good idea to keep an eye out for any kind of allergic reaction the dog may experience as the result of a mosquito bite. You may notice that your dog starts suddenly licking or scratching.

There may also be some swelling, redness, and hives, which all indicate an allergic reaction. One single mosquito bite is all it takes to cause this level of itchiness and irritation, which can cause your pup to lick, bite, and chew at their skin.


  • Avoid walking your dog at night or early morning and early evening if possible, as this is the time mosquitoes are most active.
  • Avoid walking your dog in marshy areas.
  • Plant mint near your doors (it’s a natural insect repellent).
  • Change water in your dog’s water bowl every day.
  • Make sure there is no stagnant water in your yard.
  • Keep a citronella plant or candle near your back door.
  • Plant a Eucalyptus tree. They don’t grow very large, and not only do they repel mosquitoes, but they also repel fleas too.
  • Make sure the screens in your windows don’t have any holes or tears in them.
  • Use an insect vest when walking your dog.
  • Use products that prevent/repel mosquito bites.


Now that you know more about what you can do to treat and prevent mosquito bites, let’s take a look at a few things you should keep in mind to avoid.

Avoid using any products or insect repellent on your dog that contains DEET or picaridin. OFF is a brand that contains DEET. We should also avoid using it ourselves because our dogs love to lick us and be close to us. DEET should never be used as a mosquito repellent for dogs, and you should avoid using it on your skin if you choose to use it at all.

You should also avoid using products that aren’t specifically designed for use on dogs. For example, if you find a product that says for cats only, don’t use it on your dog. Always read the labels very carefully and discuss products you intend to use with your veterinarian.

Avoid using undiluted essential oils on your dog as well. Dogs are very sensitive to the liver-toxic effects that some essential oils can cause.


Ultimately, it is up to the dog owner to protect the dog. We can do this by offering our dogs year-round heartworm prevention. This includes regular testing and preventative treatment under the care of an experienced veterinarian.

While heartworm can’t be transmitted directly from one dog to another, it can be transmitted through a bite from an infected mosquito, which is why heartworm prevention and treatment are so important to a dog’s health.

Since mosquitoes thrive in warm and humid environments, make sure to avoid areas where they are out and most active. Mosquitoes are very active during the early morning and late afternoon and evening hours. So, it is best to avoid walking our dog during these times.

Do you have issues with mosquitoes in your area? Any great remedies you’d like to share? I’m all ears?

woman kneeling in front of a dog outside in snow

Paula Simons


This article has been reviewed, fact-checked, and approved by Dr. Paula Simons DVM. You can read more about her on our About page.