Diseases of the mouth in cats can be caused by infections, injuries, tumors, or inflammatory disorders. A complete oral examination should be a part of your animal's routine physical examination, because oral diseases are most effectively treated with early diagnosis. Otherwise, many will remain hidden in the mouth and progress to an advanced stage.
Oral Inflammatory and Ulcerative Diseases
Gum disease, which was discussed earlier in this chapter, is the most common oral problem in cats. Several viruses can cause inflammation of the mouth in cats, including feline herpesvirus, feline calicivirus, feline leukemia virus, and feline immunodeficiency virus. Signs vary widely with the cause and extent of inflammation. Loss of appetite may be seen. Bad breath and drooling are common with inflammation of the mouth or tongue and saliva may be blood tinged. Pain may cause a cat to paw at its mouth and resist any attempt to examine the affected area. Lymph nodes in the region may be enlarged.
Cats with feline stomatitis have progressively worsening inflammation of the mouth, gums, and upper throat. The cause is unproved, but may be related to an inappropriate inflammatory response to a substance on the tooth surface. The most immediate sign is severe pain on opening the mouth. The cat may vocalize and jump when it yawns or opens its mouth to pick up food. An affected cat may have bad breath, excessive drooling, and difficulty swallowing. Cats often show an “approach-avoidance” reaction as they approach their food in hunger, then hiss and run off in anticipation of discomfort. If the condition is severe and of long duration, the animal may be noticeably thinner. If soft, palatable foods are being fed, the condition may be fairly severe before the signs are recognized.
Frequently, because of the cat's pain, a veterinarian will need to sedate it in order to perform an examination of the mouth. A complete history, assessment of the mouth, and evaluation for generalized diseases (such as renal failure) and/or viral infections will be included in the examination. A sample of tissue (biopsy) may be taken to help to exclude oral cancers or other specific mouth disorders.
Surgical removal of all the premolars and molars and removal of the connective tissue that attaches the teeth to the bone of the jaw is the only treatment that has provided some improvement and aided in overall longterm control. If the teeth are extracted early in the disease process, the procedure generally results in significant improvement or complete resolution of the inflammation. Antibiotics should be given if bacterial infections are present. Dietary changes, antibiotics, and antiseptic mouthwashes may help lessen signs. Animals that are unable or unwilling to eat and drink may require intravenous fluids or a feeding tube to prevent dehydration. Frequent feedings of tasty liquids and, later, semi-solid foods encourage eating.
Fungal stomatitis is caused by overgrowth of the fungus Candida albicans. It is an uncommon cause of mouth inflammation in cats. The main sign is the appearance of creamy white flat areas (plaques) on the tongue or mucous membranes. It is usually thought to be associated with other oral diseases, longterm antibiotics, or a suppressed immune system. When possible, both the underlying disease and the fungal infection itself will be treated. A balanced diet should be maintained. The outlook is guarded if the underlying disease cannot be adequately treated or controlled.
Inflammation of the Tongue
Inflammation of the tongue is called glossitis. It may be due to infection, irritation, wounds, disease, or other causes such as electrical burns or insect stings. A thread, string, or other foreign object may get caught under the tongue. Drooling and a reluctance to eat are common signs, but the cause may go undiscovered unless the mouth is carefully examined.
Glossitis is treated by the veterinarian removing any foreign objects and any broken or diseased teeth. Infection may be treated with an appropriate antibiotic. Cleaning of the wounds and use of antiseptic mouthwashes are beneficial in some cases. A soft diet and intravenous fluids may be necessary. If the animal is unable to eat well for a prolonged period, tube feeding may also be required. Short-term glossitis due to insect stings may require emergency treatment. If the glossitis is caused by another condition, the primary disease should also be treated. The tongue tissues heal rapidly after irritation and infection have been eliminated.
Soft Tissue Trauma
Injuries to the mouth can cause significant inflammation in cats, but usually respond well to treatment.
A wound along the side of the cheek may be caused by self-trauma when the tissue becomes trapped between the teeth during chewing. Surgical removal of the excess tissue prevents further injury.
Thermal (heat), chemical, or electrical burns involving the mouth may occur. The cat should be evaluated and treated for injury to other body systems, which may be life-threatening in some cases. A cat with a burn to the mouth hesitates to eat or drink, drools, and resents handling of its mouth or face. Sores and mouth inflammation may develop. These wounds can easily become infected. If you observed the burn yourself, provide the details to your veterinarian. If the cat has only a reddened mouth lining without tissue damage, it may require no treatment other than a soft or liquid diet until the soreness has disappeared. If tissue damage is extensive, your veterinarian may rinse the tissues with an antiseptic and remove any dead tissue and debris. Antibiotics may be prescribed to reduce the chance of infection.
Benign oral tumors of the mouth and throat are less common in cats than in dogs. Instead, tumors that arise are likely to be malignant.
A gingival fibroma is a benign (nonspreading) growth on the gums that usually originates near the gum line. The growth is relatively insensitive and tough and is either the color of the normal gum or more pale. The growth may become large enough to completely cover the surfaces of several teeth. Surgical removal is the most satisfactory treatment. After surgery, your cat may be prescribed a daily oral rinse to be used until the site is healed.
Epulides are another type of gum tumor. They are rare in cats. This type of tumor usually involves only a single tooth. Your veterinarian can analyze a tissue sample (biopsy) to determine the proper diagnosis and treatment.
Squamous cell carcinomas are by far the most common malignant oral tumors in cats. They commonly involve the gums and tongue and spread rapidly throughout the mouth.
Signs vary depending on the location and extent of the tumor. Bad breath, reluctance to eat, and excessive drooling are common. If the back of the mouth and throat are involved, swallowing may be difficult. The tumors frequently ulcerate and bleed. The animal's face may become swollen as the tumor enlarges and invades surrounding tissue. Lymph nodes near the tumor often become swollen before the tumor itself can be seen. A tissue biopsy is usually required for diagnosis.
The treatment and outlook depend on the specific kind of tumor and whether it has spread. Malignant melanomas are highly invasive and spread readily; consequently, the outlook is guarded to poor. Surgical removal of the tumor can extend survival and may cure the condition, but recurrence is common. In cats, squamous cell carcinoma has a poor outlook, and longterm survival is seen only if it is diagnosed and treated early. Tumor removal often requires removal of the lower jaw.
Saliva moistens the mouth and helps begin the digestion of food. As with any other part of the body, there can be medical problems involving the glands that produce the saliva. Salivary disorders in cats include excessive drooling, salivary mucocele, and tumors.
Excessive Salivation (Ptyalism or Sialosis)
Excessive salivation has 2 main causes: either the cat is producing too much saliva (a condition called ptyalism or sialosis), or it cannot effectively swallow the saliva that is produced. In either situation, the animal drools. The most serious cause of excessive drooling is rabies, so your veterinarian will want to exclude that possibility first. The underlying cause should be determined and treated. Short-term irritation of the lips and face may develop if the skin is not kept as dry as possible. Cleansing with an appropriate antiseptic solution may be recommended.
In a salivary mucocele, saliva accumulates under the skin after damage to the salivary duct or gland. Although any of the salivary glands may be affected, those under the tongue and in the jaw are most commonly involved. Usually, the cause is not determined. The signs depend on the site of saliva accumulation.
The first sign may be a nonpainful, slowly enlarging mass, frequently in the neck. A mucocele under the tongue may not be seen until it is traumatized and bleeds. A pharyngeal (throat) mucocele may obstruct the airways and result in difficulty breathing. Pain or fever may occur if the mucocele becomes infected. A veterinarian can distinguish a mucocele from abscesses, tumors, and other types of cysts by using a needle to draw a sample of fluid from inside the mucocele.
Surgery is often recommended to remove the damaged salivary gland and duct. Mucoceles in the neck or under the tongue can be managed with periodic drainage if surgery is not an option. Complete gland and duct removal is often recommended for mucoceles in the throat to avoid the possibility of future life-threatening airway obstruction.
Salivary Gland Tumors
Salivary gland tumors are rare in cats, although cats are affected twice as frequently as dogs. They usually occur in cats more than 10 years old. Most salivary gland tumors are malignant, with carcinomas and adenocarcinomas the most common types. Spread to nearby lymph nodes and the lungs is common. Tumors removed by surgery alone tend to recur, so radiation treatment, with or without surgery, offers the best outlook in most cases.
Dry Mouth (Xerostomia)
This condition occurs when saliva production is decreased. Signs include interest in eating but turning away as if the food does not taste good. Lip smacking and excessive tongue thrusting when trying to eat is another sign. The gums and mucous membranes of the mouth are dry and the teeth usually have a heavy film of plaque. Older cats with kidney failure are more at risk for this disease. Treatment is supportive care—artificial saliva substitutes and wetting the food. The condition rarely reverses itself.
Last full review/revision July 2011 by Dana G. Allen, DVM, MSc, DACVIM; Sharon Campbell, DVM, MS, DACVIM; Ben H. Colmery, DVM, DAVDC; James G. Fox, DVM, MS, DACLAM; Carlton L. Gyles, DVM, PhD, FCAHS; Walter Ingwersen, DVM, DVSc, DACVIM; Lisa E. Moore, DVM, DACVIM; Sofie Muylle, DVM, PhD; Sharon Patton, MS, PhD; Andrew S. Peregrine, BVMS, PhD, DVM, DEVPC; Stanley I. Rubin, DVM, MS, DACVIM; H. Carolien Rutgers, DVM, MS, DACVIM, DECVIM-CA, DSAM, MRCVS; Jörg M. Steiner, DrMedVet, PhD, DACVIM, DECVIM-CA; Thomas W. Swerczek, DVM, PhD