Conditions affecting the oral cavity (mouth) and pharynx (throat) are common in cats. These are collectively termed 'oropharyngeal disease'. A wide range of diseases occur, some of which are straightforward to diagnose and treat, whereas others are more problematic. With some conditions rational treatment may be difficult because we do not completely understand their cause.
Clinical signs of oropharyngeal disease
There are a number of signs which will suggest that a cat has a disorder of the mouth or pharynx, these include:
- Inappetence - the cat may show no interest in food, or may come to the food bowl and then be reluctant to eat
- Dysphagia - this refers to difficulty or discomfort in eating and swallowing - the cat may eat with obvious caution, may show discomfort, may drop food from its mouth, or may swallow with great difficulty.
- Ptyalism - this refers to excessive salivation or drooling from the mouth (sometimes bleeding may be present)
- Halitosis - this refers to an unpleasant odour to the breath
- Clawing or pawing at the mouth, and sometimes head shaking
- Weight loss may occur with inappetence
Selected diseases affecting the lips
Eosinophilic ulcer (rodent ulcer, labial ulcer)
Rodent ulcer in cat with allergic skin disease
This is a particular type of skin disease that can affect the lips, usually causing an ulcerated area on the edge of the top lips often close to the mid-line (philtrum). Over time the ulcer may enlarge and may become disfiguring and bleed. The edges of the ulcer may become swollen, and the ulcer itself is usually pink in colour. The cat may show no other signs, but with deep ulcers there may be significant pain, inappetence and reluctance to groom. The underlying cause of eosinophilic ulcers is unknown but may perhaps include (or be exacerbated by) bacterial infections, allergies, and trauma caused by the cat's rough tongue.
The disease usually has quite a characteristic appearance, but to distinguish it from more serious conditions (such as neoplasia) histological examination of a biopsy is needed. Various treatments have been used, with no single uniformly successful treatment. This may reflect more than one underlying cause or contributing factor. Antibiotics may improve the condition in some, but generally corticosteroids such as prednisolone have been found to be more helpful. A search for an underlying allergy (such as food allergy) is usually worthwhile.
Squamous cell carcinoma
This malignant neoplasia (a cancer) of the cells of the skin and can affect the lips and skin around the nose, as well as the mucous membranes lining the mouth and tongue. When it affects the lips it may cause ulceration and needs to be distinguished from an eosinophilic ulcer (via a biopsy).
Treatment options for squamous cell carcinoma include locally applied radiation therapy (brachytherapy), surgery, and cryosurgery (where affected tissue is frozen). The success of treatment depends on how far advanced the disease is, but if treated promptly, it may be possible to remove the cancer completely. (For more, see oral squamous cell carcinoma).
Harelip is a congenital (present at birth) defect, where the formation of the top lip is incomplete. It is apparent when the affected kitten is born. The defect may extend to the nose, and may be accompanied by cleft palate (a defect in the palate in the roof of the mouth). The severity of hare lip varies and a mild deficit may not interfere with normal life. Where necessary, some cases may be repaired by surgery, but in severe deficits, or where there is also a cleft palate, treatment may not be practical and euthanasia may be required.
Selected diseases affecting the oral cavity
Acute stomatitis means inflammation of the mouth of recent or rapid onset. Often this may involve inflammation of the tongue (referred to as glossitis) and/or inflammation of the throat (or pharynx, referred to as pharyngitis). Common causes of acute stomatitis include:
- FCV or FHV infection - these are the 'cat flu' viruses - both FCV (feline calicivirus) and FHV (feline herpes virus) can cause inflammation in the mouth, usually with other signs of upper respiratory tract infection such as sneezing, nasal discharge and ocular (eye) discharge. FCV infection commonly causes mouth ulceration, typically on the edges of the tongue, but sometimes other areas including the nose). FHV infection is often more severe than FCV, and signs may include quite marked pharyngitis in some cats, although the presence of ulcers is less common.
- Irritants - Many household materials, such as cleaners, paint strippers and bleach are irritants, and curiosity may sometimes lead cats to lick swallow these, causing irritation of the mouth and throat which may be very severe in some cases. Prevention is better than cure, and all such agents should be kept well away from cats.
Dental problems and gingivitis
Dental disease, periodontal disease (disease of the tissues around the teeth) and gingivitis are all very common in cats, as in other animals, see: Dental disease in cats.
Oral neoplasia (cancers)
Several types of oral neoplasia (tumours) can occur. A biopsy is needed to confirm a diagnosis of neoplasia and to determine what type of tumour is present. Malignant tumours (cancers) are much more common than benign tumours, and a cancerous growth of the epithelial cells lining the mouth (squamous cell carcinoma) is the most common tumour seen. This quite commonly affects the tongue (often the underside of the tongue), but may occur anywhere in the oral cavity, and usually affects older cats.
Tumours of the mouth rarely spread to other parts of the body but, if removed, they commonly recur locally. The exception to this rule is squamous cell carcinoma of the tonsil, which frequently spreads elsewhere. In all cases of malignant tumours, treatment is palliative and euthanasia will be necessary sooner or later.
Salivary gland disease
Salivary gland disease is rare in the cat. Very occasionally, blockage of a salivary duct can give rise to a swelling under the tongue or on the neck; these are amenable to surgical treatment. Very rarely, cats may develop tumours of the salivary glands.
Not uncommonly, foreign bodies such as small sticks or bones can become wedged across the palate (roof of the mouth) between the teeth. This is extremely uncomfortable for cats and they may be distressed and may be pawing at the mouth in an attempt to dislodge the foreign body. A short general anaesthetic may sometimes be required for the removal of these.
Cleft palate occurs in kittens as a developmental abnormality; some, but not all cases are of genetic origin. It may occur alone, or with hare lip. The condition becomes apparent soon after birth when affected kittens have difficulty in sucking milk from the queen and milk will come down the nose when hey try to feed. There is often sneezing, noisy breathing and distress. The kittens do not thrive and can develop pneumonia due to inhalation of milk. Treatment is generally not practical and euthanasia is the most appropriate course.
Selected diseases of the pharynx
Diseases of the throat and tonsils have similar signs to disease of the mouth but retching may also occur.
Pharyngitis refers to inflammation of the pharynx. Most commonly this occurs as part of upper respiratory tract viral infection (with FCV and/or FHV - see above).
Occasionally cats develop benign growths (polyps) in the nasopharynx (the passage at the back of the nose that leads into the throat). This usually causes progressive breathing difficulties, but may also cause difficulty in swallowing and loss of appetite. These polyps can usually be removed simply and successfully, but in some cases more extensive surgery may be required.