Mosquito bites on dogs: Vet's guide to protecting and treating your pooch

mosquito bites on dogs
(Image credit: Getty Images)

Not only are mosquito bites a temporary source of itchiness for your dog, but they can also carry a risk of diseases or viruses that could harm your pooch’s long-term health. One of these is heartworm, a serious and even fatal disease that mosquitoes transmit to dogs.

Thankfully we have an expert vet on hand to provide advice and information on spotting the signs and symptoms of mosquito bites, as well as how to reduce irritation and discomfort for your furry friend. 

We’ve also got advice on avoiding mosquito bites during peak seasons, when you need to contact your vet for mosquito bite treatment and what medications are available to help protect your dog, including tablets, spot-ons, or injections.

Mosquitoes aren’t the only insects that can harm your pooch either - find out how to soothe and treat flea bites and what to do if your dog has been stung by a bee or wasp.

What is a mosquito bite? 

Mosquitos are a family of flying insects that live in warm climates. They bite mammals (including dogs and humans) to feed on their blood. 

As part of this feeding process, they also inject various substances into the body which can cause irritation and swelling, leading to the redness and itchiness that mosquito bites cause.

Some mosquitos can also pass on various diseases as part of this feeding process. The most important of these for dogs is heartworm (Dirofilaria immitis).  

Can mosquitos bite dogs? 

Yes – mosquitos can bite dogs, and will quite happily feed from them. These bites can be very irritating to dogs, and can also pass on heartworm infections, too.  

What do mosquito bites look like on dogs?  

Mosquito bites themselves are very small and difficult to see. However, if a dog gets stung by a mosquito, their body will usually react to it and cause a small red bump to form on the skin. 

Signs and symptoms of a mosquito bite on a dog include: 

  • A small, red bump on the skin, which may be warm to touch 
  • Itchiness or pain, which may cause your dog to scratch or lick at the area 
  • General nervousness or irritability from the itchiness 

If the bite becomes infected, then you may also see a thick, sticky discharge from the area. 

It is easier for mosquitos to bite areas where the fur is shorter, such as the groin, belly, or face. However, if your dog still has some fur or darker skin in these areas, then it may be difficult to spot.  

Some dogs are very sensitive to mosquito bites and may develop a much larger swelling in response, which can be several centimetres wide and tall. These cause the skin to become pink and warm, but usually not as red as the small area around the bite itself. 

Brown dog lying down on floor with mosquito bite

(Image credit: Getty Images)

Treating mosquito bites on dogs 

All dogs react differently to mosquito bites. Many of them will only have minor reactions that do not need any treatment, though you should monitor the area for signs of infection. 

Signs of an infected mosquito bite in dogs include:

  • Thick, sticky discharge  
  • Severe redness 
  • Severe itchiness  

If your dog tries to lick or chew at a bite, then you should prevent this with an Elizabethan collar (or similar). Licking or chewing will make the bite more irritating, and can also lead to infection. 

You can keep a mosquito bite clean by using cool salt water. Boil some water, allow it to cool, and then measure out 500ml (1 pint) of water and add 1 teaspoon of table salt. 

Use this to gently bathe the area to keep it clean from dirt. However, do not do this too often, or you may irritate the area further. Two to three times a day is usually sufficient unless the area appears dirty. 

When to see a veterinarian 

Some dogs can have severe reactions to mosquito bites, and the area can rapidly become very swollen. If this occurs, then you should see a veterinarian as soon as possible. 

If a mosquito bite is becoming progressively redder or larger, or your dog is very distressed by it, then you should make an appointment with your veterinarian. They can prescribe creams or tablets to reduce the itching and make your dog more comfortable, and can also treat any infection that might be present. 

Heartworm prevention 

If you are living in an area where your dog may be bitten by mosquitos, then you should check with your veterinarian to find out if they need medication to prevent heartworm. 

Heartworm is a serious, often fatal illness in dogs that is difficult and expensive to treat. Prevention is much better for your dog (and your wallet) than treatment. 

There are various different medications that are available to help protect your dog, including tablets, spot-ons, or injections – speak to your veterinarian to find the options where you live.  

A dog sitting in grass

(Image credit: Getty Images)

Recovery from mosquito bites

Most dogs will recover from a mosquito bite in a few days. You should see the red area start to shrink down and become paler, and it should be less itchy for your dog.

 It may be helpful to take photos of the bite once per day, so you can track how it changes. If the bite appears unchanged after a week, then you should see your veterinarian.  

Preventing mosquito bites on dogs 

Mosquitos live and breed in stagnant water, and are most active at dawn and dusk. Try to avoid walking your dog near these kinds of areas at this time of day. 

If you have a pond or lake on your property, then there are several different ways to prevent mosquitos from breeding there. 

You can also get collars containing compounds that will repel mosquitos and stop them from biting your dog. Speak to your veterinarian for more information. 


Mosquito bites can be very irritating to dogs, and in some cases can cause significant swelling and itchiness. 

Most mosquito bites will go down by themselves, but some will need treatment from a veterinarian, especially if there is severe swelling or infection. If you live in an area where mosquito bites are a risk, you should check with your veterinarian to see if your dog needs heartworm prevention.