By John R. Lewis, VMD, DAVDC, Fellow, AVDC OMFS

Presentation

Trevor, a 10-year-old male neutered Mastiff mix, was presented recently for treatment of oral inflammation. Trevor's condition was more than just a routine case of gingivitis. His clinical signs waxed and waned. Trevor had some of his maxillary and mandibular premolars and molars removed years ago. These extractions helped transiently, but recently, he presented with signs of oral pain, including sporadic appetite and a jaw-opening reflex. In addition to his oral inflammation, Trevor had a history of inflammatory bowel disease, hypothyroidism, and arthritis. Current medications included levothyroxine 0.8 mg q12h, prednisone 10 mg SID, gabapentin 300 mg q12h, and Librela.

Trevor's owner was a veterinary nurse, and she visited us for a second opinion whether to pursue medical vs. surgical therapy (further extractions) for Trevor's condition. During a recent consult at her place of work, her veterinary dentist recommended medical therapy with cyclosporine and metronidazole.

Diagnosis

Upon examination at our facility, the mandibular lymph nodes were moderately enlarged. There was severe inflammation and ulceration of the labial mucosa that lay against the areas of the maxillary canines, incisors and lower premolars (Figures 1A and 1B). There was mild inflammation of the lateral edges and ventral surface of the tongue. Of note, there was no mucosal inflammation in the areas where prior extractions had been performed. The pattern of ulceration was nearly pathognomonic for CCUS.

What is it?

CCUS is an immune-mediated oral mucosal disease characterized by ulcerative lesions, severe halitosis, and oral discomfort associated with contact of mucosal surfaces with plaque-retentive surfaces of the teeth. These mucosal lesions have been referred to as "kissing lesions" since inflammation is most severe where the mucosa "kisses" or lays against the teeth. Histologic examination of 20 dogs in one study revealed a subepithelial lichenoid band (interface mucositis) where B cells, T cells, and Forkhead-box protein 3 (FoxP3)- and interleukin-17-expressing cells were present. These cells might play a role in the underlying immune response.¹

A more recent study examined histology of lesions from 24 dogs with chronic ulcerative stomatitis. Three histologic subtypes of ulcerative stomatitis were determined: lichenoid, deep stomatitis, and granulomatous. Immunofluorescence did not support an autoantibody-mediated autoimmune disease process.²

Treatment

Plaque control is key, but the painful nature of the lesions makes home care, such as daily brushing, very difficult. Mild cases may be managed with frequent professional cleanings, meticulous home care, and medical therapy. Medical management alone is rarely curative.

One study examined treatment with cyclosporine and metronidazole. Ten client-owned dogs with a biopsy-confirmed diagnosis consistent with CCUS were prescribed cyclosporine (5 mg/kg) for one week, followed by the addition of metronidazole (15-20 mg/kg), both administered orally once daily. The cyclosporine dosage interval was lengthened over time. Dogs were observed for six months and evaluated using a 32-point Canine Ulcerative Stomatitis Disease Activity Index (CUSDAI). The results demonstrated a combination of cyclosporine and metronidazole was effective in minimizing the clinical signs of CCUS and in reducing CUSDAI scores.³

In Trevor's case, I recommended extracting his remaining teeth as the ultimate form of plaque control/minimization. I did not look forward to extracting his firmly rooted incisors, canines, and premolar teeth, but based on how normal the mucosa appeared in the areas of prior extractions, this suggested a favorable outcome would be obtained without the potential side effects of long-term cyclosporine and metronidazole, including substantial effects of metronidazole on the gut microbiome.⁴

Over the course of two extraction sessions, Trevor's remaining teeth were extracted, and the decrease in oral inflammation was profound (Figures 2A and 2B).

Controlling CCUS inflammation is not only important from a pain/quality-of-life standpoint, but also for maintaining healthy bone beneath the soft tissue. I have seen a number of cases of canine stomatitis that have progressed to osteomyelitis/osteonecrosis after months or years of uncontrolled stomatitis, and this has been documented in literature.⁵

Patient outcome

Trevor's mom recently provided an update to me, seven weeks after completion of the extractions. She stated, "Trevor is doing really, really well. Like a new dog! I am so grateful he will hopefully get to enjoy the rest of his life without mouth pain."

You've got to love dentistry for the ample opportunities to make substantial improvements in the lives of pets and their caretakers. Updates like this one from Trevor's mom makes the challenges of extracting ankylosed teeth worthwhile.

John R. Lewis, VMD, DAVDC, FF-OMFS, practices at Veterinary Dentistry Specialists and teaches at Silo Academy Education Center, both in Chadds Ford, Pa.

References

1. Anderson JG, Peralta S, Kol A, Kass PH, Murphy B. Clinical and histopathologic characterization of canine chronic ulcerative stomatitis. Vet Pathol. 2017;54(3):511-519.
2. Anderson JG, Kol A, Bizikova P, Stapelton BP, Ford K, Villarreal A, Jimenez RJ, Vasilatis D, Murphy BG. Immunopathogenesis of canine chronic ulcerative stomatitis. PLoS One. 2020;15(1):e0227386.
3. Ford KR, Anderson JG, Stapleton BL, Murphy BG, Kumar TKS, Archer T, Mackin AJ, Wills RW. Medical management of canine chronic ulcerative stomatitis using cyclosporine and metronidazole. J Vet Dent. 2023;40(2):109-124.
4. Pilla R, Gaschen FP, Barr JW, Olson E, Honneffer J, Guard BC, Blake AB, Villanueva D, Khattab MR, AlShawaqfeh MK, Lidbury JA, Steiner JM, Suchodolski JS. Effects of metronidazole on the fecal microbiome and metabolome in healthy dogs. J Vet Intern Med. 2020;34(5):1853-1866.
5. Boutoille F, Hennet P. Maxillary osteomyelitis in two Scottish terrier dogs with chronic ulcerative paradental stomatitis. J Vet Dent. 2011;28(2):96-100.