Canine Chronic Ulcerative Stomatitis in dogs (CCUS)

(previously known as C.U.P.S.)

This is a relatively common and frustrating condition to manage, usually seen in small-sized and terrier breeds. It was previously known as Canine Ulcerative Paradental Stomatitis (C.U.P.S.). The previous term CUPS is no longer appropriate as approximately 40% of ulcerations were also seen associated with edentulous areas.  Ulcerations can be present on the mucosal surfaces of the mouth, lateral margins of the tongue, mucocutaneous junction of the lips, glossopalatine folds and the palate.



Image 1: Note inflammatory lesions extending beyond the mucogingival margins.

Note ulcerative lesions extending from the buccal mucosa to the mucocutaneous junction and tongue.
Ulceration to the buccal mucosa (‘kissing ulcers’) and note stage 4 periodontal disease concurrently

Image 2 and 3: Note ulcerative lesions extending from the buccal mucosa to the mucocutaneous junction. Note ulceration to lateral and ventral borders of the tongue.

Image 4: Ulceration to the buccal mucosa (‘kissing ulcers’) and note stage 4 periodontal disease concurrently.


Differential diagnoses for lesions presenting in similar manner are:

  • Pemphigus vulgaris
  • Bullous pemphigoid
  • Erythema multiforme
  • Lupus erythematosus
  • Epitheliotrophic T-cell lymphoma
  • Uraemic stomatitis

Before the diagnosis and treatment is initiated for CCUS, these conditions must be eliminated from the differential diagnoses. Since the treatment for other immune-mediated diseases is very different from the treatment for CCUS, it is important to make the distinction early in the management of the case.

Breeds like Maltese, Cavalier King Charles Spaniel, Labrador Retrievers and Greyhounds have a higher reported incidence.

The most common findings are halitosis, oral pain, difficulty eating and weight loss. There is usually excessive salivation of a thick, viscous nature. The saliva is sometimes blood stained. CCUS and periodontal disease are two separate conditions that may be present singly or together.

A full haematology and biochemistry panel will help confirm the health status of the patient.


We do not know the precise aetiology of CCUS. We do know that these individuals have an abnormal immune system response and appear intolerant of the presence of normal dental plaque. The presence of plaque leads to a greater than normal level of local inflammatory reaction.

Case Management - Plaque Control

In mild cases and in cases that can tolerate home care, the initial focus by both vet and owner must be scrupulous plaque control. Starting with a diligent, professional scale and polish. Teeth that have a limited future due to any pathology (periodontal disease or other), should be removed. In this regard, these cases are very similar to Feline Chronic Gingivitis Stomatitis (FCGS), as they are also intolerant to normal levels of dental plaque.

Control measures are generally for life. Diligent, even twice daily, removal of plaque with a chlorhexidine-based product should then be instituted after prophylactic cleaning. This can be a spray, rinse or a gel/toothpaste. Petdent gel (Chlorhexidine Gluconate 0.12%) and Anident oral wash (Chlorhexidine Digluconate 0.12%) are easily available and well tolerated by dogs and cats. (

Tooth brushing may be hard to achieve until the lesions are under control. Until the oral pain settles, wipe the gel inside the lips to start with. Once the lesions improve you can advise the use of a soft bristled, small headed toothbrush.


Frequent professional scaling and polishing will be required. This might mean as frequent as every 3 - 4 months, if the lesions look like they are recurring.



Images 5 and 6: Images of the mouth before and after plaque disclosing solution.

Case Management - Extractions

Extraction of any teeth affected by stage >3 periodontal disease should be performed as presence of pathology will exacerbate inflammation.


Strategic extraction of teeth associated with the worst of the ulceration may be indicated. In some cases, elective cheek teeth (premolars and molars) or even full mouth extractions may be appropriate to reduce the plaque burden within the mouth.



Images 7 and 8: Image of the mouth and x-ray.

dog mouth before extractions
dog mouth after extractions

Images 9 and 10: Images of mouth before and after extractions

Case Management – Medical therapy

Regardless of treatment modality, all treatment options require adequate pain management. As the ulcerative lesions tend to be painful, appropriate levels of analgesia is required. As the condition is chronic, analgesia should be continued or at least 4-6 weeks to manage oral comfort to the point where daily homecare is tolerated. Multi-modal analgesics used should depend on concurrent illness and medications and compliance in administering medications.

Occasional and controlled immuno-modulatory treatment may be needed in some cases.

Management of CCUS cases can be frustrating and costly. It is imperative that investigation, diagnostics and management be systematic, with good client communication of expectations to ensure the best outcome for client and patient. The Stomatitis Activity Index (SDAI) is an invaluable tool for aiding diagnosis and assessing response to treatment.




Ford R., Anderson J., Stapleton B., at al. Medical management of canine chronic ulcerative stomatitis using cyclosporine and metronidazole. J Vet Dent 2023, Vol. 40(2) 109-124.

Anderson J, Kol A, Bizikova P, et al. Immunopathogenesis of canine chronic ulcerative stomatitis. PLoS One. 2020;15(1): e0227386. doi:0.1371/journal.pone.0227386

Anderson J, Peralta S, Kol A, Kass P, Murphy B. Clinical and histopathologic characterization of canine chronic ulcerative stomatitis. Vet Pathol. 2017;54(3):511-519.

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