Mouth Inflammation and Ulcers (Chronic) in Dogs

Oral ulceration and chronic ulcerative paradental stomatitis (CUPS) is the inflammation of any of the soft tissue structures in the mouth, which may involve the cheeks, gums, tongue, lips, throat, and palate or sublingual areas. This condition is a form of peradental disease that causes red, raised, ulcerated lesions in the buccal or labial mucosa where the soft tissues rest against the teeth. Any area of the buccal or labial mucosa may be involved, however, most of these lesions are found in the area of the maxillary canines and fourth premolars. CUPS is caused by an immune system reaction to bacteria and plaque on the teeth. It is essentially an allergy to the bacterial buildup on the teeth.

There is often a profound amount of inflammation at the gingiva, the buccal and palatal mucosa, lip margins, and tongue epithelium. It is common to find significant ulcers on tissue that comes in contact with the teeth; these are called “kissing lesions” or “kissing ulcers”.

Also known as ulcerative stomatitis, idiopathic stomatitis, and lymphocytic-plasmacytic stomatitis, the condition is a painful and often debilitating disease of the mouth causing inflammation which, in most cases, is going on for months if not years.


Certain breeds of dogs are at a higher risk of acquiring this condition. These include Maltese, Cavalier King Charles Spaniels, Cocker Spaniels and Bouvier des Flandres.


Common symptoms associated with this condition include

Bad breath (halitosis)

Swollen gums (gingivitis)

Faucitis (inflammation of the cavity at the back of the mouth – the fauces)

Pharyngitis (inflammation of the back of the mouth, continuous into the larynx – the pharynx)

Buccitis/buccal mucosal ulceration (tissue of the inner cheeks)

Thick, ropey saliva (ptyalism)


Loss of appetite (anorexia)

Mucosal ulceration on the gums that meet the lips – also called "kissing ulcers"

Plaque on teeth

Exposed, necrotic bone (alveolar osteitis and idiopathic osteomyelitis)

Scar formation on lateral margins of the tongue from prolonged inflammation and ulceration 

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