Mouth Pain in Dogs

Dogs can’t always tell us when they are in pain. They often go about their day acting like everything is fine. Mouth pain in dogs is a type of pain that can be a little harder to figure out the exact problem on your own but it’s also easier to tell they are in pain. Certain mouth disorders may also lead to more complicated conditions in other parts of the body as things like plaque travel through the bloodstream. It’s important to keep up with dental care to prevent many painful mouth disorders in dogs.

Common Symptoms:

  • Excessive salivation
  • Trouble eating
  • Not eating at all
  • Not letting you touch their face
  • Drooling
  • Whimpering
  • Halitosis (bad breath)
  • Change in behavior or displaying protective behavior
  • Resisting head pets
  • Change in activity level
  • Decrease in appetite, eating slower or dropping food
  • Red or swollen gums
  • Glossitis

Causes of Mouth Pain

Canine Stomatitis

Canine Stomatitis is also known as Chronic Ulcerative Paradental Stomatitis (CUPS). It is a very painful condition in the mouth due to ulcerations. Oral discomfort, an inability to open their mouth, foul breath, drooling, and a lack of appetite are all signs of CUPS. Many dogs have had teeth cleanings in the past that don’t appear to help anymore. Mild to advanced calculus, mild to advanced gingivitis, and the typical “kissing lesions” or ulcerations on the mucosa (checks) that contact the tooth surfaces are common in these patients. These patients have developed serious ulcers on the inside of their cheeks and others have lesions on the tongue along with having a plaque intolerance. Some of the most affected breeds include Maltese, King Charles Spaniel, Terrier, German Shepherd, and Greyhound. Ost dogs don’t have covert clinical signs of canine stomatitis but just because there aren’t any signs doesn’t mean it’s not painful. A biopsy is used for diagnosis to show areas of necrosis in the center of the mouth lesions.


  • Professional dental cleaning and possible extraction for plaque control. Find a dental specialist near you. (link to dentists)
  • Strict routine of at-home cleaning after a thorough dental cleaning.
  • Anti-plaque sealants.
  • Severe cases may require full extraction.
Fungal Stomatitis

Fungal stomatitis is the overgrowth of the fungus Candida albicans. Fungal stomatitis is a rare oral inflammation in dogs. Mouth pain, foul breath, drooling, inability to feed, and bleeding or open sores on the tongue or mucous membranes are all clinical signs to watch out for. It’s normally linked to other oral infections, long-term antibiotic therapy, or an immune system that’s been weakened. Both the underlying condition and the fungal infection can be treated in most cases. Diagnosis usually involves an oral examination to which the dog is put under anesthesia as it’s otherwise painful for the dog. This will often be followed by a bacterial culture, biopsy, blood tests and x-ray. To aid your pet’s rehabilitation, closely follow your veterinarian’s food guidelines. Your veterinarian will also suggest a treatment plan to combat the infection that is causing the issue. 


Insect Bites

Insect bites in pets are a common problem and while can sometimes be harmless, certain insects can cause serious health complications and pain. It’s important to note the three categories of insects that sting: Vespidae (yellow jackets, and wasps, hornets), Formicidae (i.e. fire ants), and Apidae (i.e. honeybees, African killer bees). While it can take 20 stings from one of these to be lethal in mammals, it can happen quickly if a pet disturbs a hive or colony. Clinical signs that your dog has been bit or stung by an insect include swelling and redness at the site of the bite, hives, swollen face or muzzle, localized pain at the site of the bite (can vary from mild to severe), puncture wound, and itchiness. Dogs experiencing anaphylaxis may have diarrhea, vomiting, weakness, seizures, respiratory distress, cardiovascular arrest, and collapsing. Initial diagnosis is based on the clinical signs being presented. Blood samples might also be taken to help determine an allergic reaction.


  • Treatment is based on type of bite, how many, and severity of clinical signs.
  • Removal of stinger or other insect parts (if applicable).
  • Antihistamines and anti-inflammatory agents such as corticosteroids.
  • Treatment for anaphylactic shock includes supportive measures such as intravenous fluids, corticosteroids, oxygen therapy, and epinephrine.
Necrotizing Sialometaplasia

Also known as salivary gland necrosis or infarction, Necrotizing Sialometaplasia is when the salivary gland ducts and lobules have squamous metaplasia, and the salivary gland lobules have ischemic necrosis. It affects dogs of all ages but is most common in 3–8 year old dogs (mostly smaller breeds such as beagles). Depressed, nauseous, and anorectic dogs are typical symptoms. Salivary gland enlargement, which may be unpleasant to palpate, weight loss, ptyalism, retching, gagging, regurgitation, and vomiting are all clinical symptoms of Necrotizing Sialometaplasia. When diagnosing, all other possible causes must first be excluded and at that point, surgical removal only helps improve the affected area slightly or not even at all. 


  • This disease is still being studied and no effective treatment has been found.
  • Pain relief medication, antibiotics, NSAIDs, anti-inflammatory doses of glucocorticoids, and parasite control have yielded positive results.
Oral Lacerations

Oral lacerations are a common source of mouth pain in dogs but overall, the less common type of laceration compared to other parts of the body. They can also be easily missed depending where in the mouth they are located. These types of lacerations are usually caused by eating something sharp that splinters like a stick or older bone. Other causes can be from blunt trauma, dog bites or bites from other animals. Signs of oral lacerations in your dog’s mouth include reluctance to eat, swelling of the lips, tongue or cheeks, and open, visible laceration, plus or blood in the mouth, bad breath and/or scratching at their mouth. Oral lacerations occuring on the lips are easily identified but those within the mouth or cheeks may be harder to see.


  • Cleaning and removal of any debris, dirt, or unhealthy tissue in the laceration prior to stitches depending on the severity. Cleaning of the wound can be done at home with a saline rinse.
Peripheral Odontogenic Fibromas

Peripheral odontogenic fibromas (also known as Euplis) is a slow-growing benign oral tumor that also happens to be the most common mass found in dogs. They are also more commonly found in brachycephalic breeds (i.e. pugs, bulldogs, etc.). When left untreated, these tumors become extremely invasive. While more common in dogs over the age of six, they can occur in dogs of all ages. Euplis are firm masses that evolve from the gums, more specifically the ligament of the tooth in question. While several masses may be present, these masses usually exist alone. They have the potential to grow very large. Symptoms include drooling, mass on the jaw, mass on the mouth, swelling, discomfort while eating, dropping food difficulty closing jaw, chattering of the jaw, reluctance to be touched on the head. The only chance of recovery is through removal via surgery.  A biopsy is required to make a definitive diagnosis.


  • Surgical removal of the mass, the associated tooth, and possibly the bone if it has extended into it which includes curettage of the tooth socket.
  • Radiation therapy.
Salivary Gland Tumors

While salivary gland tumors in dogs are considered rare, they are more likely to be seen in dogs over the age of 10. There is not much history on breed or sex predisposition but it’s believed that Poodles and Spaniel breeds may be predisposed. A biopsy is normally needed for a definitive diagnosis for salivary gland tumors.. A fine needle aspirate can help differentiate between cancerous and noncancerous causes and a CT scan can be used to assess the level of the disease as well as penetration into surrounding structures in the body. Salivary glands are malignant more times than not. Local penetration and metastasis to regional lymph nodes and lungs, as well as local recurrence following surgical excision, are both common. 


  • Surgical removal. 
  • Radiation therapy.
  • Chemotherapy.
  • Medical management with antibiotics for infections.
Salivary Mucocele

Salivary Mucocele is the Inflammation of the salivary glands. This is caused by saliva that has collected in the tissues after leaking from a compromised salivary gland or salivary duct. Salivary mucocele can be noted as an increasing, painless swelling of the neck or oral cavity. Mucoceles are often mistakenly referred to as salivary cysts. There are four categories of salivary mucocele:

  • Cervical Mucocele: This is the most common form of mucocele. It’s a saliva accumulation in the upper neck, under the jaw, or in the intermandibular area (between the jaws). 
  • Sublingual Mucocele (ranula): This mucocele is located on the floor of the mouth opposite the tongue and is another common site for the development of a mucocele. This is often seen in conjunction with a mucocele in the cervical region. 
  • Pharyngeal Mucocele: This kind of mucocele is much less frequent. It’s a variant of the cervical mucocele, but the fluid is almost completely contained inside the throat (pharynx).
  • Zygomatic Mucocele: This is a very uncommon and rare form of mucocele in which the saliva comes from the small zygomatic salivary glands just below the eye.

The actual cause of salivary mucocele is fairly unknown but is believed to be a result of physical trauma such as from choke collars, bite wounds, or chewing on foreign material. The salivary glands are generally easy to feel for diagnosis, and mucoceles, with the exception of the pharyngeal mucocele, are easily recognized as a soft, fluctuant swelling that is painless. Tumors and abscesses may resemble one other in appearance, however, they are usually either solid or painful.


  • Removal of the salivary gland.
  • Aspiration or draining of the mass can provide temporary relief but the mass will likely return.
Skinfold Dermatitis

Skinfold dermatitis can appear on any part of a dog’s body and is also present in the lips. The most common symptoms include persistent moisture or discharge, red, inflamed, or otherwise irritated skin, and foul or musty odor. Dogs with wrinkly, droopy faces are the most affected such as English Bulldogs and Pugs. Things like dirt, bacteria, and even food get caught in those wrinkles. Occasionally, the best cleaning practices, however, will not be enough to remove all potential problems. This is particularly true for dogs with deep creases, where the upper tooth rests directly on the lower lip, and for heavy drooling dogs. Hygiene may or may not be a factor in some situations. A reaction to a certain food or a plastic dish may also be the cause of the foul odor. Diagnosis is usually based on observation of the physical, clinical signs.


  • Keep cleansed with a medicated skin cleanser (such as chlorhexidine, miconazole, or sulfur/salicylic acid).
  • Combination of antibiotics and steroids administered topically, orally, or by injection.
  • Skin removal in severe cases.
  • Soothing balms.
Soft Tissue Trauma of the Mouth

Soft tissue is basically any tissue that is not bone, and soft tissue trauma is essentially any type of damage that is causing symptoms such as pain. When soft tissue trauma is present in the mouth, signs include hesitating to eat or drink, drooling, and resenting handling of their mouth or face. Oral soft tissue trauma is often seen in the lips, tongue, or tonsils. One type of trauma is chewing trauma which is when during chewing, tissue gets entrapped between the teeth. Mouth burns are also considered soft tissue trauma which can be thermal, chemical, or electric in state. To diagnose, dogs will usually be put under anesthesia and the mouth will be examined for the trauma and look for bruising, lacerations, remnants of splinters or abscess, as well as taking the physical symptoms into account.


  • Place an ice pad on the affected area.
  • Limit mobility of the affected area.
  • Severe damage often requires surgery.
Trenchmouth (Necrotizing Ulcerative Gingivitis)

Trench Mouth is both extremely uncommon and hard to spot. Extreme gum inflammation (gingivitis), ulceration, and mortality of the tissue covering the mouth define this relatively rare disease in pets. Trench Mouth first shows itself with reddening and swelling of the gingival margins and interdental papillae, which is painful, bleeds easily, and can proceed to gingival recession. The cause of this Trench Mouth is unclear, although it has been speculated that normal mouth bacteria and other microorganisms might be to blame after a predisposing factor either improves or reduces the mouth’s tolerance to infection. Stress, excessive corticosteroid use, and inadequate diet are all possible causes. The dog’s clinical history of progressive oral inflammation is looked at for diagnosis as well as elevations in globulin, fine needle aspirates, and histology.


  • Professional dental cleaning and full or possible mouth extraction for plaque control. Find a dental specialist near you. 
  • Strict routine of at home cleaning after a thorough dental cleaning.
  • Antibiotics such as amoxicillin-clavulanate, ampicillin, clindamycin, metronidazole, or tetracyclines.
  • Oral Antiseptics.
Viral Warts and Papillomas

clusters that are caused by a virus, similar to human warts, making it transferable from dog to dog. A dog may even have hundreds to thousands in its mouth. These are usually present on the roof of the mouth, inside the cheeks, tongue, or lips. It takes one to two months for warts to show up after the time of infection making it harder to pinpoint exactly where they came from. Warts that show up as a result of canine papillomavirus often have a jagged surface and may have a cauliflower-like appearance which may have a whitish, grayish, or fleshy coloring to them. Dogs under the age of 2 years old are usually affected the most. Oral papillomas often regress on their own within a few weeks but further treatment is also available, especially if they don’t regress or if there is such an abundance of them that eating and chewing becomes difficult. Diagnosis of papillomas is usually done through visual identification of the wart-like masses but surgical biopsy with full histopathology may be done if the condition is atypical.


  • Surgically removed.
  • Frozen off cryogenically.
  • Antiviral doses of interferon. 
  • Topical medication called imiquimod.