Dog’s Lip is Swollen and Red: How to Help

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lip and mouth inspection at the vet

This article was updated on September 1st, 2023

A dog’s lips may seem like minor parts of their face. After all, they’re not as active as the tongue or as expressive as the eyes, so you probably don’t think much about them until they show up swollen. A dog’s lip that is swollen and red can be the result of many different conditions, so let’s look at what you can do to help.

Top Causes of Swollen, Red Lips in Dogs

swollen red lip on dog

Swelling and redness in a dog’s lip can stem from a variety of things, some more severe than others. Bug bites, stings, dental issues, allergies, injuries, and tumors top the list. Some are very minor and require little further attention, and some are severe and need professional care as soon as possible. So which causes are which?

1. Insect bites and Stings

Insects may be beneficial for many things in our dog’s environment, but they can also be downright pesky. When a bug is making a nuisance of itself, your dog’s first instinct is to snap or bite at it, hoping it’ll go away. All of that is fine until the bug fights back and bites or stings your dog’s mouth. Insect bites and stings elicit an inflammatory reaction that causes swelling, redness, heat, and pain, often in a dog’s lips. These swellings usually show up suddenly and can become quite large. You may also find a stinger lodged in the skin or a small, bloody area where the bite went down.

Most insect bites are harmless and the swelling will go away with an antihistamine, icing, and time; however, rarely dogs can have an allergic reaction that leads to anaphylactic shock or the swelling can be severe enough to make breathing difficult. For this reason, contact your veterinarian if you think your dog was bitten or stung in the lips or face.

Swollen face of dog stung by a bee

You can also click this picture to see a swollen lip on a dog after a bee sting.

2. Allergies

Dogs can have allergies to bug bites but also to things in their environment, including pollen, grasses, plants, and chemicals. Some allergic reactions can cause swelling of the lips and face. There may be redness, heat, and pain as well. Dogs may also be sneezing or have a rash anywhere on their body. As with insect stings, most allergic reactions will calm down with antihistamines and removal of the allergen, but swelling can be severe enough to cause difficulty breathing. Be sure to get a hold of your vet if you notice any moderate to severe swelling of your dog’s lips or face.

English bulldog with red swelling lips and eyes from allergy

3. Dental Issues

Dental disease is very common in our canine companions. So common, in fact, that it’s estimated that over 80% of dogs over three years of age have some stage of dental disease. Dental disease can cause bad breath, bleeding gums, and loose teeth. It can also cause tooth root abscesses when those nasty bacteria get to the tooth roots and set up shop. This can create swellings in the jaw and even in the lip covering it, mainly in the lower jaw. You may also notice a foul odor, drainage, and drooling, and your dog probably won’t want to eat due to the pain. Tooth root abscesses are going to need antibiotics and a veterinary dental, so get them to the vet as soon as you can.

View more pictures of tooth root abscesses.

4. Injuries

Dogs love to stick their noses in things, which can sometimes get them into trouble. Injuries to the lips or nose can cause swollen and red lips. It may be due to a small scrap with another animal, a well-positioned kick, or a run-in with a vehicle. You may notice other wounds or bleeding along with the swelling, and your pup may be a little disoriented or act as if they have a headache.

If your pup suffered any trauma to their head or mouth, it’s always best to have them checked out by a veterinarian to help ensure that they don’t have further injuries that could be serious.

5. Tumors

Tumors and other lumps and bumps can show up anywhere on your pup, including the lips. These lip lumps and bumps can be both malignant or benign and may look and act differently depending on the type. Tumors of the lips can be slow-growing or grow large very quickly. This makes it important to have any new lumps, bumps, or swelling checked out by your veterinarian as soon as you can for the best outcome.

warts on a dog's lips

Learn more about lip lumps and bumps (with pictures and vet advice).

6. Other causes

Snake bites, foreign objects, and minor irritations can also lead to a dog with swollen and red lips (View this dog with swollen lips and face after being bitten by a rattlesnake). These can be very minor or quite severe, causing your dog a lot of distress. If you notice any swelling or redness in your dog’s lips, be sure to contact your vet to determine the cause and how to best treat it.

At-Home Treatments for Dog With Swollen and Red Lips

If you notice a swelling in your dog’s lips, you should really contact your vet to make sure it’s not something very serious. But in the meantime, try some of these at-home remedies.

  1. Find the cause. Inspect the swelling, if your dog is willing, to see if you notice any wounds, stingers, or rotten teeth that could indicate the cause.
  2. Note the size and timeframe with pictures if possible. If the swelling is growing rapidly, you may want to show your vet how quickly it is growing.
  3. Give an antihistamine if your veterinarian suggests it. They will provide you with the best medication to use as well as the dose.
  4. Apply ice or a cold pack to the swelling. Don’t apply it directly to the skin.

When to Worry About Swollen or Red Dog Lips

You’ll want to check out any new swellings or lumps on your dog’s lips, but that doesn’t mean that you always need to rush right over. If your pup’s lip is only mildly swollen and they’re not having difficulty breathing, eating, or drinking, you may wait and see if things get better with a little time.

If your pup’s lips and face or throat are swollen so severely that they are having trouble breathing, get them to the vet immediately. Any pus or smelly drainage should be addressed as soon as possible, and if your dog isn’t feeling like eating or drinking, get that veterinary care as soon as you can.

Veterinary Treatment for Dog Lips that are Swollen or Red

Your veterinarian is going to start with a thorough exam, including a history of when the swelling showed up, if it’s grown or gotten smaller, and any other signs your pup is showing. Hopefully, you’ll know the cause, but if not, your vet may have to dig a little deeper by checking your dog’s teeth, doing an x-ray, or taking a sample of the swelling with a needle and syringe.

Based on those findings, they will start treatment. Allergic reactions, including insect stings and bites, are often treated with antihistamines and icing, and anti-inflammatories for those more severe cases.

Disclaimer: This content is not a substitute for veterinary care. Always consult with your vet for health decisions. Learn more.

Tooth root abscesses will be treated with antibiotics, a dental, and possibly removal of the tooth. Injuries may be treated with antibiotics, anti-inflammatories, and other medications. Tumors may need surgical removal with or without chemotherapy and radiation.


A dog lip that is swollen and red from an insect sting may only cost you around $75 for the exam and medications, while a tumor of the lip can run $2,000+ for surgery and aftercare. Everything else is going to fall somewhere in between, but generally speaking, most swollen lips are going to be under $500.

Can a Vet Diagnose Swollen Lips With a Picture or Video Call?

Telemedicine has become popular in the veterinary world lately, but it can’t completely replace the need for a vet to get their hands on an animal. Some swollen lips can be seen this way and others are still going to need an in-office appointment.

Of course, if your dog is in distress, having trouble breathing or eating and drinking, don’t even consider a video call. If the swelling also has a foul odor or discharge, telehealth is not an option. If you suspect a tumor, you’ll need to make the in-office journey.

Those dogs that have mild swelling that is probably related to an insect bite or mild irritation are the only ones that you can fully rely on telemedicine.


  • Dr Chyrle Bonk, Veterinarian

    Dr. Chyrle Bonk received her Master in Animal Science from the University of Idaho and her Doctorate of Veterinary Medicine (DVM) from Oregon State University in 2010. She has over 10 years of experience in small animal veterinary practice, working for a veterinary clinic in Idaho.

Disclaimer: This website's content is not a substitute for veterinary care. Always consult with your veterinarian for healthcare decisions. Read More.


  1. I’m grateful for the information and picture. My 8-year old 110# black has a red fleshy spot on his lower lip. Not sure for how long…? But it’s been a while. Must be bigger to grab my attention. We live on 5 wooded acres in western Washington. He does seem to have allergies with skin, sneezing, etc. Will continue to watch for now as we are on a fixed income. He has no pain or difficulty eating. He’s a lab! LoL

    • Hey there Shari and thanks for this new question.
      If this lump has been there for more than 2 weeks, I’d want it looked into. This is especially true given his age and breed. The vet may biopsy it, to determine if it could be cancerous. If so, the sooner it is removed, the better the prognosis.

      While allergies can cause lip lesions/swellings, they would not cause any sort of fleshy mass to grow.

      “The information on this website is not a substitute for in-person veterinary care. Always seek advice from your veterinarian if you have concerns about your pet’s medical condition.”

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