Chronic ulcerative paradental stomatitis (CUPS) is a painful condition in dogs that is also known as ulcerative stomatitis, idiopathic stomatitis, and lymphocytic-plasmacytic stomatitis. The hallmark lesion is a paradental, or so-called kissing, ulcer.1 Patients with CUPS are usually inappetent or anorectic, and the chief complaint from owners is usually fetid halitosis and
drooling. CUPS can affect any dog, but Maltese are overrepresented, and a familial predilection has been shown (Figure 1). Cavalier King Charles spaniels also seem to be genetically predisposed.2 While dogs of any age can be affected, I have rarely seen CUPS in patients under 1 year old.
Figure 1 : The classic presentation of CUPS: A Maltese that refuses to eat and whose breath is affecting every room in a
CUPS lesions are characterized histopathologically by a predominance of lymphocytes and plasmacytes, indicating that the disease
is inflammatory rather than infectious. The presumed antigen stimulating the inflammation is bacterial plaque,3 or in terms that pet owners can understand, the dogs become allergic to the bacteria that live on their teeth. Some veterinary
dentists refer to this condition as plaque intolerance or plaque
As the inflammatory condition continues, gingivitis and advanced periodontitis (deep pocket formation, gingival recession,
periodontal bone loss, furcation exposure) can occur concurrently. The change from predominantly gram-positive to predominantly
gram-negative bacterial flora that occurs with periodontitis seems to fuel the inflammation of CUPS, suggesting to me that
antigens from the gram-negative bacteria may trigger an even stronger inflammatory response in affected dogs.
The severe pain dogs experience from CUPS lesions makes it difficult for owners to provide adequate dental home care. This
lack of home care and the patient's unwillingness to chew allow more plaque to accumulate, and the vicious cycle continues.
Affected dogs exhibit various clinical signs including halitosis (sometimes severe), inappetence or anorexia, ptyalism, and
oral pain (pawing at mouth, chattering jaw movements). Other signs may include abnormal chewing movements, eating difficulties,
difficult prehension, and oral hemorrhage. Affected dogs often will not chew on their toys and will refuse the hard portions
of their diets.
Figure 2 : A paradental, or kissing, ulcer (black arrow) on the oral mucosa apical to the right maxillary canine tooth. Note
how this tissue will contact the tooth surface when the mouth is closed.
On oral examination, gingivitis, stomatitis, and, sometimes, advanced periodontitis are observed. The classic distribution
of the stomatitis is paradental (Figure 2). The lesions on the oral mucosa correspond with areas that touch the teeth's surfaces. The lesions are red, sometimes slightly
raised, and often ulcerated. In addition to the buccal mucosa, the lateral mucosa of the tongue is often inflamed and ulcerated
where it touches the lingual mandibular teeth's surfaces (Figure 3). The most severe lesions are often found associated with areas of gingival recession. Concurrent sublingual granuloma, or
gum chewers lesions, may exacerbate the problem on the lingual mandibular mucosa. Sometimes, dogs with CUPS will have a concurrent
lip fold dermatitis (intertrigo) adding to the oral discomfort as well as an overall foul odor. The connection between these
two conditions is most likely that excessive drooling from the CUPS contributes or exacerbates the lip fold dermatitis. Another
finding consistent with CUPS is mandibular lymphadenopathy.
Figure 3 : Gingivitis, stomatitis, cheilitis, and inflammation along the tongue's lateral border. To diagnose CUPS, oral biopsy
samples of affected areas need to be evaluated.