Inflammation of the oral tissues can be either primary or secondary. Inflammation in the oral cavity may affect the gingiva (gingivitis), periodontium (periodontitis), oral mucosa (stomatitis), tongue (glossitis), tissues over the pterygomandibular raphe and glossopalatine arches (caudal stomatitis), tissues extending from the pharynx down the throat (faucitis), palate (palatitis), or pharynx (pharyngitis). The nature and severity of the lesions vary greatly depending on the etiology and duration of the disease.
Periodontal disease, including gingivitis and periodontitis, is the most common oral problem in small animals. Gingivitis is a normal gingival inflammatory response to the presence of bacterial plaque on an adjacent tooth surface. Periodontitis (inflammation of the periodontal ligament with loss of attachment) results from the combination of bacterial periodontal pathogens and the immune response of susceptible individuals that together destroy the supportive tissues and bone around the tooth. (Also see Periodontal Disease in Small Animals.)
A periapical infection caused by endodontic disease is the most common cause of a parulis, or gum boil, that manifests as a circular raised area of inflamed granulation tissue with a central draining fistula on the gingiva. A periodontal abscess is a less common cause of a parulis. The tract can be followed to the primary periodontal or periapical lesion, and the etiology resolved (Also see Endodontic Disease in Small Animals).
Other causes for oral inflammatory conditions include immunopathy (eg, autoimmune, immune deficiency), chemical agents, infectious disease, trauma, metabolic disease, developmental anomalies or conformational anatomy that predisposes to irritation or inflammation, burns, radiation therapy, or neoplasia. Infectious agents that have been associated with oral inflammation, glossitis, stomatitis, and oral ulcerations include feline herpesvirus, feline calicivirus, feline leukemia virus, feline immunodeficiency virus, canine distemper virus, Bartonella henselae, and certain Leptospira serovars. Traumatic stomatitis may be seen after oral exposure to plant material (embedded plant awns) or fiberglass insulation. When chewed, plants of the species Dieffenbachia may also cause oral inflammation and ulcers. Thallium is the major heavy metal responsible for oral lesions; incidence of this toxicity is low. Uremia can cause stomatitis and oral ulcers. Recurrent oral ulcerations are also seen in gray Collies with cyclic hematopoiesis.
Signs vary widely with the cause and extent of inflammation. Anorexia may be seen, especially in cats. Halitosis and drooling are common with caudal stomatitis or glossitis, and saliva may be blood tinged. The animal may paw at its mouth and resent any attempt to examine the oral cavity because of pain. Regional lymph nodes may be enlarged.
Feline Caudal Stomatitis
(Ulceroproliferative faucitis/stomatitis, Palatoglossitis, Plasma cell stomatitis, Lymphocytic-plasmacytic stomatitis)
Feline caudal stomatitis (FCS) is a relatively uncommon (3% of feline dental problems) but serious condition of cats. Affected cats present with progressively worsening oral inflammation and discomfort. More significantly, the area around the glossopalatine arches and the tissues over the pterygomandibular raphe (between the retromolar areas of the upper and lower jaws) are severely ulcerated, friable, inflamed, and proliferative. Severe ulceroproliferative inflammation that involves this area bilaterally in the back of the mouth is pathognomonic for FCS. The cause is unproved but is suspected to result from an inappropriate inflammatory response in affected individuals to one or more antigens. A high percentage of affected cats (100% in some studies) are chronic carriers of feline calicivirus. FCS may be caused by the sum of multiple sensitivities in an individual, with antigen on the tooth surfaces, including the root surfaces and periodontal ligament, exceeding a threshold.
The most immediate sign is severe pain on opening the mouth. Cats vocalize and jump when they yawn or open their mouth to eat. Halitosis, ptyalism, and dysphagia may be seen. Cats often show an “approach-avoidance” behavior 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, weight loss may be evident. The disease is slowly progressive and may not be recognized until the lesions have become severe. Submandibular lymphadenopathy is sometimes present. Pain often prevents adequate examination of the oral cavity without sedation or anesthesia.
Diagnosis is made by visual identification of bilateral ulceroproliferative changes in the tissues around the glossopalatine arches during oral examination. In advanced cases, the cat will strongly object to opening the mouth. Additional tests include virus isolation (eg, calicivirus and herpesvirus), retroviral tests, and evaluation for systemic disease (eg, renal failure). Although a definitive association with Bartonella infection has not been shown, testing has been recommended. In atypical cases (unilateral involvement, usually proliferative focal lesion), biopsy and histopathologic evaluation is required to rule out oral neoplasia or other specific oral disorders. Most biopsy samples collected from chronic inflammatory or ulcerated lesions reveal a predominance of lymphocytes and plasma cells, which indicate the chronic inflammatory nature of the lesion without elucidating the primary etiology.
Extraction of all the premolars and molars and removal of the associated periodontal ligaments by alveolar curettage is the only treatment that has provided lasting improvement and aided in overall longterm control. This treatment provides significant improvement in 80% of affected cats when it is done early in the disease course and no root tips or fragments are left behind. Chronically affected cats that have been treated medically for many months have a poorer prognosis after surgery. Dental radiographs of areas with missing teeth are required to check for retained roots. Any persistent root fragments must be removed, because they will prevent improvement. Postoperatively, amoxicillin-clavulanate should be administered for 1 wk, followed by clindamycin for 1 wk, followed by metronidazole for 1 wk. Culturing the lesions and performing susceptibility tests are rarely indicated even in chronic or recurrent infections. Symptomatic treatment for FCS includes dietary changes (nonallergenic, soft palatable foods), antibiotics, and topical antiseptics (eg, 0.1% chlorhexidine solution or gel). Cats that are unable or unwilling to eat and drink should be given parenteral or subcutaneous fluids to prevent dehydration. Placement of a nasoesophageal, pharyngostomy, or gastrostomy tube should be considered in debilitated cats that do not respond to therapy. Frequent feedings of palatable liquids and, later, semisolid foods encourage eating. For pain that persists in spite of extractions, maintenance therapy with oral prednisone or triamcinolone can be helpful.
Many other treatments for FCS have been reported, including maintaining good oral hygiene, treating periodontal disease, regular dental prophylaxis, chlorambucil, cyclosporine, laser therapy, bovine lactoferrin, progestins, gold salts, azathioprine, hypoallergenic diets, CO2 laser, cryotherapy, electrofulguration, and radiosurgery. None of these provide longterm resolution. Some reports of response to therapy with feline recombinant interferon-ω are promising. Glucocorticoid administration alone usually results in significant and immediate clinical improvement from modulation of the excessive inflammatory response, but it is not recommended except as a last resort. Without surgery, repeated injections of methylprednisolone or triamcinolone, or oral maintenance therapy with prednisone or prednisolone are frequently required. This treatment becomes progressively less effective and eventually completely ineffective. In addition, cats that have received repeated treatments with glucocorticoids have a poorer prognosis once the teeth are extracted. Extraction of all premolars and molars or full-mouth extractions often results in significant improvement or complete resolution of the inflammation if performed early in the course of the disease and before multiple glucocorticoid treatments.
Chronic Ulcerative Stomatitis
Characteristics of chronic ulcerative stomatitis (also called chronic ulcerative paradental syndrome or CUPS) include severe gingival inflammation, multiple sites of gingival recession and dehiscence, and large areas of ulcerated labial mucosa adjacent to the surfaces of large teeth. The problem commonly affects Greyhounds, and it has also been seen in Maltese, Miniature Schnauzers, Labrador Retrievers, and other breeds.
Diagnosis is by clinical observation of the typical oral lesions after ruling out other etiologies such as uremic stomatitis, caustic stomatitis, or specific infectious agents. The characteristic lesion is the contact ulcer that develops where the lip or cheek mucosa contacts the tooth surface, most commonly on the inner surface of the upper lip adjacent to the upper canine teeth. These lesions have also been termed “kissing ulcers,” because they are found where the lips “kiss” the teeth. An immune profile should be done, and a biopsy considered for histopathology.
The underlying pathology is an immunopathy that results in an excessive local inflammatory response to the antigens in dental plaque. Eliminating, or at least minimizing, plaque through professional cleaning and meticulous home oral hygiene (twice daily tooth brushing) may resolve the problem. However, even slight residual plaque on the tooth surfaces will perpetuate the inflammation and ulcerations. Supplemental antibacterial measures, eg, topical chlorhexidine gluconate rinses or gels and possibly antimicrobial treatment with metronidazole, should also be used. In severe cases, topical anti-inflammatory preparations to modulate the inflammatory response may provide comfort. Discomfort caused by the ulcers complicates efforts to brush the teeth and administer oral medications. In those cases in which discomfort is severe and the owners are unable or unwilling to brush the teeth, extraction of all teeth associated with ulcers may be necessary to remove the contact surfaces on which plaque accumulates. Although this may aid in control of the lesions, it is not curative, because plaque forms on mucosal surfaces in the mouth, including the tongue. In some cases with complete extractions, animals continue to develop lesions due to hyperimmune response to the plaque.
Lip Fold Dermatitis and Cheilitis
Lip fold dermatitis is a chronic moist dermatitis seen most commonly in breeds that have pendulous lips and lower lateral lip folds (eg, spaniels, English Bulldogs, Saint Bernards) that have prolonged contact with saliva. The lesions may be exacerbated when poor oral hygiene results in increased salivary bacterial levels. The lower lip folds can become very malodorous, inflamed, uncomfortable, and swollen.
Lip wounds, resulting from fights or chewing on sharp objects, are common and vary widely in severity. Thorns, grass awns, plant burrs, and fishhooks may embed in the lips and cause marked irritation or severe wounds. Irritants such as plastic or plant material can produce inflammation of the lips. Lip infections may develop secondary to wounds or foreign bodies or can be associated with inflammation of adjacent areas. Direct extension of severe periodontal disease or stomatitis can produce cheilitis. Licking areas of bacterial dermatitis or infected wounds can spread the infection to the lips and lip folds. Other causes of inflammation of the lips include parasitic infections, autoimmune skin diseases, and neoplasia.
Clinical Findings and Diagnosis
Inflammation of the lips and lip folds can be acute or chronic. Animals with cheilitis may paw, scratch, or rub at their mouth or lip; have a foul odor on the breath; and occasionally salivate excessively or be anorectic. With chronic infection of the lip margins or folds, the hair in these areas is discolored, moist, and matted with a thick, yellowish or brown, malodorous discharge overlying hyperemic and sometimes ulcerated skin.
Cheilitis due to extension of infection from the mouth or another area of the body usually is detected easily because of the primary lesion.
Medical management of lip fold dermatitis includes clipping the hair, cleaning the folds 1–2 times/day with benzoyl peroxide or a mild skin cleanser, and keeping the area dry. Topical diaper rash cream applied daily may be helpful. Surgical correction (cheiloplasty) of deep lip folds is a more longlasting remedy.
Cheilitis that is unrelated to lip folds usually resolves with minimal cleansing, appropriate antibiotics if a bacterial infection is present, and specific treatment of primary etiologies (eg, autoimmune skin disease). Wounds of the lips should be cleaned and sutured if necessary. Treatment of periodontal disease or stomatitis is necessary to prevent recurrence.
Infectious cheilitis that has spread from a lesion elsewhere usually improves with treatment of the primary lesion, but local treatment also is necessary. With severe infection, hair should be clipped from the lesion and the area gently cleaned and dried. Antibiotics are indicated if the infection is severe or systemic.
Mycotic stomatitis caused by overgrowth of the opportunistic yeast Candida albicans is an uncommon cause of stomatitis in dogs and cats. It is characterized by stomatitis, halitosis, ptyalism, anorexia, oral ulceration, and bleeding from the oral tissues. It is usually thought to be associated with other oral diseases, longterm antibiotic therapy, or immunosuppression. Diagnosis is confirmed by culture of the organism from the lesion or by histologic evidence of tissue invasion.
Any existing underlying local or systemic diseases affecting the oral cavity should be treated. Ketoconazole or a related benzimidazole should be administered until the lesions resolve, after which antibiotic therapy should be discontinued. An adequate level of nutrition should be maintained. The prognosis is guarded if predisposing diseases cannot be adequately treated or controlled.
Acute Necrotizing Ulcerative Gingivitis (ANUG)
(Necrotizing ulcerative gingivostomatitis, Ulceromembranous stomatitis, Necrotizing ulcerative stomatitis, Vincent's stomatitis, Trenchmouth)
This relatively uncommon disease of dogs is characterized by severe gingivitis, ulceration, and necrosis of the oral mucosa. Fusobacterium spp and spirochete organisms (Borrelia vincenti), normal inhabitants of the mouth, have been suggested to cause this disease after some predisposing factor increases their numbers or decreases the local resistance of the oral mucosa. The role, if any, of these organisms in causing disease is unknown. In people, Bacteroides melanogenicus intermedius may play a more important role. Other potential factors are stress, excess glucocorticoid administration in susceptible dogs, and poor nutrition.
The disease appears first as reddening and swelling of the gingival margins and interdental papillae, which are painful, bleed easily, and may progress to gingival recession. Extension to other areas of the oral mucosa is common, resulting in ulcerated, necrotic mucous membranes and exposed bone in severe cases. Halitosis is severe, and the animal may be anorectic because of pain. Ptyalism sometimes occurs, and the saliva may be blood tinged. Differential diagnoses include severe periodontal disease, autoimmune skin disease, uremia, neoplasia, and other systemic disease associated with oral lesions.
Diagnosis is made by exclusion of other etiologies.
Treatment of periodontal disease, debridement of lesions, oral hygiene, antibiotics (amoxicillin-clavulanate, ampicillin, clindamycin, metronidazole, tetracyclines), and oral antiseptics (0.1% chlorhexidine solution or gel) are indicated.
Glossitis, an acute or chronic inflammation of the tongue, may be due to infectious (calicivirus, herpesvirus, rhinotracheitis virus, leptospirosis), physical (irritation from excess calculus and periodontal disease, foreign bodies that penetrate or become lodged under the tongue, traumatic wounds), or chemical agents; metabolic disease (uremia, hypoparathyoidism, diabetes); or other causes such as electrical burns and insect stings. Foreign body glossitis is especially a problem in longhaired dogs that attempt to remove plant burrs from their coats.
Drooling and a reluctance to eat are common signs, but the cause may go undiscovered unless the mouth is carefully examined. Periodontitis may result in reddening, swelling, and occasionally ulceration of the edge of the tongue. A thread, string, or other linear foreign body may get caught under the tongue. There may be no inflammation of the dorsal surface of the tongue, but the ventral surface is painful, shows acute or chronic irritation, and frequently is lacerated by the foreign body. Porcupine quills, plant material, and other foreign materials may become embedded so deeply that they are not palpable. Insect stings cause acute swelling of the tongue.
In chronic cases of ulcerative glossitis, a thick, brown, foul-smelling discharge (occasionally with bleeding) may be present. Frequently, the animal is reluctant to allow oral examination.
Fissured, or plicated, tongue (lingua dissecta) describes a textural variation of the dorsum of the tongue with deep central or lateral longitudinal grooves. The fissure deepens with age and is therefore thought to be acquired from some extrinsic factor. However, it may also represent a developmental anomaly. The groove often becomes deeply filled with hairs that act as a local irritant, causing inflammation and discomfort.
Any foreign bodies or hairs should be removed, and broken or diseased teeth removed or treated. Bacterial infectious glossitis should be treated with an appropriate systemic antibiotic. Debridement and 0.12% chlorhexidine mouthwashes are beneficial in some cases. Lingual curettage is sometimes required if foreign material is embedded in the tongue. A soft diet and parenteral fluids are administered as needed. If the animal is debilitated and unable to eat well for a prolonged period, a nasoesophageal, pharyngostomy, or gastrostomy tube to allow for nutritional support should be considered. Acute glossitis due to insect stings may require emergency treatment.
If the glossitis is secondary to another condition, the primary disease should be treated. The tongue tissues heal rapidly after irritation and infection have been eliminated.
Last full review/revision March 2012 by Gregg A. DuPont, DVM, Fellow AVD, DAVDC