Rabbits are a popular mammalian pet in the U.S., and there is increasing demand for advanced veterinary care from the approximately one million households that own rabbits.1 One of the most common disease presentations for this species is dental malocclusion, and a common sequela of this chronic disease is dental-associated (odontogenic) abscesses. The predisposing factors and treatment options for dental disease and odontogenic abscesses in this species differ significantly from those of other domestic mammals, such as dogs and cats. Dental anatomy All rabbit teeth are high-crowned (hypsodont) and grow continuously throughout their life without developing anatomic roots (aradicular elodont). Their teeth are composed of a clinical crown (visible above the gingiva), reserve crown (sub-gingival), and apex. None of their teeth has anatomic roots; therefore, the term “tooth-root abscess” is not applicable for use in rabbits. Instead, odontogenic abscesses are more accurately referred to as apical or periapical abscesses in this species. While this may seem like a subtle or even academic difference, it is important as the clinical implications and treatment of a true tooth root abscess in a dog or cat versus a periapical abscess in a rabbit are dramatically different. Rabbits are normally anisognathic—their maxilla is wider than the mandible. This can lead to uneven wear patterns on their teeth if they are not properly aligned. This is particularly evident if they are fed a pelleted or grain-based diet, as the chewing motion for these foods (more vertical) is different than the chewing motion for their normal vegetation of hay, greens, or grasses (more horizontal). Rabbit incisors can grow as much as 1 mm per day, and their cheek teeth (premolars and molars) can grow up to 3 mm per week,2 which further reinforces the importance of proper dental occlusion and wear patterns. Etiology of dental disease and odontogenic abscesses There are numerous proposed etiologies for dental disease in rabbits, which indicate this is most likely a multifactorial process. Two broad categories include congenital and acquired dental disease. Congenital dental disease is the least common and encompasses abnormalities such as prognathism and brachygnathism. There are numerous contributing factors to acquired dental disease, including, but not limited to: dietary factors, calcium/Vitamin D deficiencies, trauma, periodontitis, and aging. Most importantly, dental disease in rabbits is almost always chronic and progressive, a condition referred to as the progressive syndrome of acquired dental disease (PSADD).3 Early changes in this disease include elongation of the teeth apices, which may be palpable along the ventral mandible. This can progress to malocclusion and alterations of the shape and structure of the teeth.4 In addition, the periodontal space often becomes widened due to inflammation of the periodontal ligaments and/or loss of surrounding alveolar bone.2,3 This periodontal pocketing can subsequently be colonized by bacteria, which can lead to periapical abscessation. In severe acquired dental disease, the tooth apex can penetrate through the periosteum of the surrounding alveolar bone, which can also lead to periapical abscessation and osteomyelitis.5 Uncommonly, penetrating foreign bodies, such as blades of hay or other ingesta, can become lodged in the periodontium and cause odontogenic abscessation. Clinical presentation According to a recent retrospective article on odontogenic abscesses in rabbits from a single institution, the average age of rabbits presented for this condition was 4.5 years (range 6-134 months), with no sex predilection. Lop-eared rabbit breeds were the most common, and hyporexia/anorexia was the most common presenting complaint.6 Rabbit odontogenic abscesses often cause variable degrees of focal facial swelling (Figure 1) and can be found in a variety of locations. However, abscesses are most often found on the ventrolateral aspect of the mandible or the lateral maxilla.5 This is in concordance with another study that found 71 percent of odontogenic abscesses in rabbits occurred in the mandibular quadrants, while only 29 percent affected the maxillary quadrants.6 Figure 1. Three rabbits, each with varying degrees of right-sided facial swelling secondary to odontogenic abscesses. Photos courtesy Dr. Olivia A. Petritz Odontogenic abscesses can also form in the retrobulbar space, leading to unilateral exophthalmos (Figure 2). Palpable abscesses are often firm, spherical, non-mobile, and non-painful. Rabbits may display a variety of other clinical signs, depending on the location and extent of the abscessation and concurrent dental disease. These include dysphagia, ptyalism, and reduced appetite/fecal output. However, even a rabbit with a large odontogenic abscess could have no systemic signs. Interestingly, it is rare for a rabbit to be pyrexic with dental-associated abscesses. While uncommon, not all focal facial swellings in rabbits are abscesses, and neoplasia should always be a differential (Figure 3). Figure 2. An adult rabbit with unilateral exophthalmos secondary to a retrobulbar abscess confirmed on skull computed tomography (CT). Photos courtesy Dr. Sarah Ozawa Figure 3. A nine-year-old rabbit presented for reduced appetite and a firm left-sided lateral mandibular swelling was noted (A) that was also visible on intraoral examination (B). A large lytic mandibular mass was confirmed on computed tomography (CT) of the skull (C), and fine needle aspiration was consistent with an osteosarcoma. Photos courtesy Dr. Olivia A. Petritz In addition, not all facial abscesses in rabbits are odontogenic (Figure 4) in origin; however, this is also rare. Figure 4. A 5-year-old rabbit was referred for a chronic facial abscess (A). The abscess was surgically debrided (B), and no underlying dental involvement was noted on radiographs (C) nor on computed tomography (CT) of the skull. Photos courtesy Dr. Olivia A. Petritz Diagnostics If accessible, fine needle aspiration (FNA) of a suspected odontogenic abscess could be considered for initial diagnosis to confirm the presence of purulent material. A complete blood count is often not useful in the diagnosis of odontogenic abscesses in rabbits, as they rarely mount a significant inflammatory response, even in the presence of significant abscessation. Plasma biochemistries could be considered if anesthesia is planned for the diagnostic and/or treatment of an odontogenic abscess. Imaging is one of the most important diagnostic tools for odontogenic abscesses, typically including skull radiographs and/or a skull CT scan. As radiographs are insensitive for evaluation of the soft tissues of the skull, a skull CT scan is highly recommended, especially for potential surgical planning and overall prognosis. Increasing numbers of general practices have access to cone-beam CT, which offers higher resolution for bones and teeth, but provides poor soft-tissue contrast compared to a conventional CT. Therefore, a cone-beam CT may still be superior to a skull radiograph, but it still has significant limitations compared with a conventional CT. A retrospective article published in 2020 reviewed CT findings from 100 rabbits with dental disease from a single institution.7 Those authors found widening of both the periodontal ligament space and the interproximal dental space was statistically correlated with periapical abscess formation, and 76 percent of all rabbits had signs of periodontal ligament space widening, suggesting that a CT scan could detect early dental abscessation before it became clinically evident. Another retrospective study found 85 percent of rabbits with odontogenic abscesses confirmed on CT also had concurrent dental malocclusion, which fits with the etiology of this disease. In addition, that study found 21 percent of rabbits had concurrent rhinitis or sinusitis, and 16 percent had concurrent otitis media—both of which are diseases that are challenging to diagnose based on radiographs alone.6 This further reinforces the benefits of performing a skull CT compared with standard skull radiographs in rabbits with suspected dental abscesses. Medical treatments Rabbit abscesses are typically well encapsulated with a thick, poorly vascularized capsule, which limits systemic antibiotic penetration into the abscess. As rabbits have heterophils rather than neutrophils, their purulent material is much thicker than other domestic mammals. Therefore, lance and drain placement for treatment of any abscesses is not recommended in rabbits. Even if surgical intervention is elected for treatment of an odontogenic abscess, systemic antibiotics are still recommended. Ideally, antibiotic selection should be based on both aerobic and anaerobic cultures. A recent review article on odontogenic abscesses in pet rabbits summarized the most common aerobic bacterial species isolated from rabbit abscesses based on six peer-reviewed studies—core pathogens included Pseudomonas aeruginosa, Pasteurella multocida, Escherichia coli, Staphylococcus spp., and Streptococcus spp.2 Several previous studies also recovered anaerobic bacteria (Fusobacterium spp., Peptostreptococcus spp., and others) from rabbit abscesses, highlighting the importance of both testing for and treating anaerobes.6,9 Crăciun et al. also summarized the antibiotic resistance patterns in all previously published studies of rabbit odontogenic abscesses to date and found concerning patterns of multidrug resistance in certain bacterial species, most notably Stenotrophomonas maltophilia and Burkholderia spp. However, low or no resistance was reported for Pasteurella multicide, Streptococcus spp., and Staphylococcus spp.2 Due to a plethora of reasons, medical management with long-term systemic antibiotics may be the only treatment option available for an odontogenic abscess in a rabbit. In one retrospective study of 35 cases, the success rate of medical therapy alone for the treatment of rabbit odontogenic abscesses was 25 percent.6 If a culture and sensitivity of the abscess is not an option, the most commonly prescribed empirical antibiotics are azithromycin, enrofloxacin, metronidazole, parenteral penicillin G procaine, trimethoprim-sulfamethoxazole (TMS), or a combination thereof.2,6,8 Unfortunately, there are too many variables to make broad recommendations on empirical antibiotic selection for all rabbits with odontogenic abscesses. The current retrospective data on treatment outcomes and culture results are primarily from single institutions, which inherently may reflect institutional bias in antibiotic selection and potential differences in bacterial flora amongst different patient populations. Surgical treatments Surgical intervention, in addition to systemic antibiotics, is the treatment of choice for most odontogenic abscesses in rabbits.2,5,6,9-11 However, similar to many common conditions in companion animals, there is no consensus statement on the recommended treatment for this condition. The most common surgical approach reported is incision into the abscess capsule, debridement and flushing of the abscess contents, followed by marsupialization of the capsule to facilitate continued flushing of the abscess capsule post-operatively.5 There are several reported modifications to this surgical approach, including more radical debridement of the diseased tissue,10 tooth removal via extraoral and/or intraoral approach,11 and packing the abscess capsule with antibiotic-soaked gauze and or antibiotic-impregnated beads.2,9 Combinations of these approaches have also been reported.5 Each of these techniques has been evaluated retrospectively with variable success rates. However, these successful outcomes are difficult to compare and to extrapolate to individual clinical cases due to patient variability and surgical experience in this species. Lancing and flushing of the abscess without additional debridement or marsupialization anecdotally has a lower success rate and is not recommended in rabbits.5 Olivia A. Petritz, DVM, DACZM, graduated from Purdue University and then completed several internships and a residency in the field of zoo and exotic animal medicine. Dr. Petritz became a diplomate in the American College of Zoological Medicine in 2013, specializing in zoological companion animals (exotic pets). Petritz started an exotics service at a specialty hospital in Los Angeles, Calif., following her residency, and is currently an associate professor of Avian and Exotic Animal Medicine at North Carolina State University. References American Veterinary Medical Association. U.S. Pet Ownership & Demographics Sourcebook. 2024 ed., American Veterinary Medical Association, 2024. Crăciun, Smaranda, and George Cosmin Nadăş. “Odontogenic Abscesses in Pet Rabbits: A Comprehensive Review of Pathogenesis, Diagnosis, and Treatment Advances.” Animals 15.13 (2025): 1994. Crossley DA. Oral biology and disorders of lagomorphs. Vet Clin North Am Exot Anim Pract 2003;6:629–659 Harcourt-Brown FM. The progressive syndrome of acquired dental disease in rabbits. J Exot Pet Med 2007;16:146–157. Capello, Vittorio. “Surgical treatment of facial abscesses and facial surgery in pet rabbits.” Veterinary Clinics: Exotic Animal Practice 28.3 (2025): 645-672. Levy, Ivana, and Christoph Mans. “Diagnosis and outcome of odontogenic abscesses in client-owned rabbits (Oryctolagus cuniculus): 72 cases (2011–2022).” Journal of the American Veterinary Medical Association 262.5 (2024): 658-664. Artiles, Charles A., et al. “Computed tomographic findings of dental disease in domestic rabbits (Oryctolagus cuniculus): 100 cases (2009–2017).” Journal of the American Veterinary Medical Association 257.3 (2020): 313-327. Minich, David J., et al. “High incidence of complications following intraoral extractions and treatment of periapical infections in the management of domestic rabbit (Oryctolagus cuniculus) dental disease (51 cases).” Journal of the American Veterinary Medical Association 263.2 (2025): 193-198. Taylor, W. Michael, et al. “Long-term outcome of treatment of dental abscesses with a wound-packing technique in pet rabbits: 13 cases (1998–2007).” Journal of the American Veterinary Medical Association 237.12 (2010): 1444-1449. Jekl, Vladimir, Edita Jeklova, and Karel Hauptman. “Radical debridement guided by advanced imaging and frequent monitoring is an effective approach for the treatment of odontogenic abscesses and jaw osteomyelitis in rabbits: a review of 200 cases (2018–2023).” Journal of the American Veterinary Medical Association 261.S2 (2023): S52-S61. Girard, Nicolas. “Surgical treatment of facial abscesses and jaw osteomyelitis of dental origin using extraoral tooth extraction in the domestic rabbit: a case series.” Journal of Veterinary Dentistry 41.2 (2024): 93-105.
