Rabbit Dermatology.

The majority of rabbit skin disease presentations can be divided into pruritus, alopecia, scaling, and nodules. Some disease will have more than one of these clinical signs. Ectoparasites, bacterial and fungal infections, and neoplasia account for most of the causes seen. Diagnostic tests include skin scraping and cytology, microbial culture, and biopsy. Therapy is dependent on cause. In addition to discussing the various causes and their treatments, important clinical care points are noted.

Approach to the pruritic horse.

Pruritus in the horse may be due to several causes, the most common being a hypersensitivity response to salivary proteins in the Culicoides genera, which may coexist with atopic dermatitis, also known as an environmental allergy to pollens, molds, dust, storage mites, etc. Less common etiologies are food allergy and contact allergy, the latter often caused by owners applying various products to the skin. Other ectoparasites, such as Chorioptes mites, may also initiate pruritus. Secondary bacterial infections (usually Staphylococcus spp) may be pruritic in and of themselves. This article reviews the questions that need to be asked of owners to obtain a relevant history, always important for any organ system, but perhaps none more so than the skin. The various clinical findings such as alopecia and crusts and their location on the horse, diagnostic methods such as intradermal or serum testing for allergies, and subsequent hyposensitization are also discussed. Therapeutic options currently available for the potential underlying diseases, in particular for the hypersensitivity reactions to Culicoides spp or environmental allergens, are reviewed with the studies of hyposensitization over the last 40 years, as well as medications that may be effective. While the most common causes of pruritus in the horse are known, the current understanding of the pathophysiology still needs to be investigated, and consequently, the most effective treatments for those causes need to be improved. Newer research is discussed that may eventually add to the diagnostic and therapeutic options currently available for the pruritic horse.

Evaluation of aural masses submitted as inflammatory polyps in 20 dogs (2000-2020).

BACKGROUND: Canine non-neoplastic aural polypoid masses (APMs) are uncommon, with few published studies. OBJECTIVES: The aim of this retrospective study was to characterise the clinical presentation, diagnostic imaging and histopathological results for APMs submitted as aural inflammatory polyps (AIPs). ANIMALS: Twenty dogs with APMs evaluated at a veterinary teaching hospital. MATERIALS AND METHODS: Cases were selected by searching computerised medical records from 2000 to 2020, using keywords 'canine', 'aural/otic polyp' and 'aural/otic inflammatory mass'. Histological samples and medical records were reviewed. RESULTS: In 14 of 20 dogs, external ear canal masses were characterised by keratinised squamous epithelium with or without adnexa. Tympanic bulla origin was confirmed in four of 20 dogs by the presence of cuboidal to ciliated columnar epithelium, with or without squamous epithelium. The site of origin could not be determined in two dogs. Diagnostic imaging (MRI or CT) confirmed APM presence in 14 of 20 dogs. Otitis media was diagnosed in four of four tympanic bulla APMs and seven of 13 ear canal APMs. In 18 of 20 dogs, debulking, traction avulsion, and total ear canal ablation and bulla osteotomy led to APM resolution in two of eight, four of six and four of four dogs, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Type of epithelium was a key feature in determining the APM origin, and interpretation in conjunction with video otoscopy and diagnostic imaging was crucial. Canine APMs more commonly arose from the ear canal. Tympanic bulla APMs and APMs of undetermined origin were comparable to feline AIPs. Regardless of APM origin site, debulking had the greatest likelihood of recurrence.

Retrospective case series: Necrotising fasciitis in 23 dogs.

BACKGROUND: Necrotising fasciitis (NF) is a rare, rapidly progressive subcutaneous bacterial infection. Few studies have characterised NF in dogs. HYPOTHESIS/OBJECTIVES: To retrospectively describe clinical and laboratory findings, with treatments and outcomes, in dogs with NF. ANIMALS: Twenty-three client-owned dogs treated at a veterinary teaching hospital between 1998 and 2021. MATERIALS AND METHODS: Medical records and laboratory data from 23 dogs diagnosed with NF were reviewed. RESULTS: Male dogs were significantly over-represented (p = 0.003). The most common presenting complaint was sudden lameness. Infection occurred in one or two limbs in 19 of 23 dogs, with right hindlimbs most often affected (13 of 23). Pitting oedema was evident in 14 of 23 dogs. Antibiotic and nonsteroidal anti-inflammatory drugs were administered before presentation in nine and 13 of 23 dogs, respectively. Common clinicopathological abnormalities included hypoalbuminemia, hyponatremia, elevated liver enzymes, elevated creatine kinase, increased bands and lymphopenia. Streptococcus canis was isolated from 18 of 23 dogs. Histopathological features included acute necrosis and severe neutrophilic inflammation. Fifteen dogs were euthanised or died, while surgical intervention led to survival in eight of 23 dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Dogs presenting for acute swelling of a limb with oedema should have the diagnosis of NF considered and early surgical intervention might increase survival.

Locally extensive follicular hamartomas with concurrent follicular cysts and dermoid cysts on the head of a dog.

A 5-month-old, male intact Australian shepherd dog was presented with nodular lesions affecting the dorsal head. A locally diffuse form of follicular hamartomas, with concurrent dermoid cysts and follicular cysts, was diagnosed by histopathological examination. Complete surgical excision of the affected skin and closure with a subdermal plexus advancement flap led to long-term resolution.

Un berger australien mâle intact âgé de 5 mois a été présenté avec des lésions nodulaires affectant la face dorsale de la tête. Une forme localement diffuse d'hamartomes folliculaires, avec des kystes dermoïdes et des kystes folliculaires concomitants, a été diagnostiquée par examen histopathologique. L'éxérèse chirurgicale complète de la peau atteinte et la fermeture avec un lambeau d'avancement du plexus sous-cutané ont conduit à une résolution à long terme.

Un perro pastor australiano macho entero de 5 meses de edad se presentó con lesiones nodulares que afectaban el dorso de la cabeza. Mediante examen histopatológico se diagnosticó una forma localmente difusa de hamartomas foliculares, con quistes dermoides y quistes foliculares concurrentes. La escisión quirúrgica completa de la piel afectada y el cierre con una zona avanzada en colgajo del plexo subdérmico condujo a una resolución a largo plazo.

Pathology in Practice.

In collaboration with the American College of Veterinary Pathologists.

Skin disease in goats (Capra aegagrus hircus): a retrospective study of 358 cases at a university veterinary teaching hospital (1988-2020).

BACKGROUND: Goats are important worldwide as a source of milk, meat, fibre and hide, and as show animals and pets. HYPOTHESIS/OBJECTIVES: To document the type, signalment associations and prevalence of skin disease in a referral hospital population. ANIMALS: Case population at a university veterinary teaching hospital. METHODS AND MATERIALS: Retrospective study by searching computerised medical records of goats seen between 1 January 1988 and 1 January 2021. Key words employed were "alopecia, caseous lymphadenitis, Chorioptes, dermatitis, dermatophyte, dermatophytosis, goat, lice, louse, mange, mite, pemphigus foliaceus, Psoroptes, ringworm, seborrhea, skin" RESULTS: Of 1,488 records reviewed, 358 (24%) goats had skin disease recorded. Seventy-nine (22.1%) of 358 goats presented primarily for skin disease. The Nigerian Dwarf goat breed was at higher risk of developing skin disease (P < 0.0002). As goats aged, the odds for developing skin disease was higher [odds ratio (OR) = 1.07 per year, 95% confidence interval (1.04, 1.12)] as was the predilection for malignant skin tumours (P < 0.001). Sex was not associated with skin disease (P = 0.98). The most common clinical sign was exfoliative dermatitis, noted in 94 (26.4%) of 358 goats. The most common diagnoses were pediculosis, bacterial skin disease and squamous cell carcinoma. Less frequent diagnoses were Chorioptes spp. infestation, contagious ecthyma (orf), coronitis/interdigital dermatitis, demodicosis, dermatophytosis, Psoroptes spp. infestation, dermatophilosis and pemphigus foliaceus. CONCLUSIONS AND CLINICAL IMPORTANCE: Skin diseases are common in goats. Nigerian Dwarf goats and older goats are at greater risk of developing skin disease; Nigerian Dwarf goats had a predilection for malignant skin tumours. Clinicians should include a dermatological examination in goats regardless of the reason for presentation.

Pharmacokinetics of mycophenolate mofetil following single-dose intravenous and single- and multiple-dose oral administration and clinicopathologic effects of mycophenolate mofetil following long-term oral administration in healthy horses.

OBJECTIVE: To characterize the pharmacokinetics of mycophenolate mofetil (MMF) following single-dose IV or PO administration, characterize the pharmacokinetics of MMF following long-term PO administration, and describe the clinicopathologic effects of long-term MMF administration in horses. ANIMALS: 12 healthy adult horses. PROCEDURES: In phase 1, 6 horses received a single IV (2.5 mg/kg) or PO (5 mg/kg) dose of MMF in a randomized balanced crossover assessment (≥ 2-week interval between administrations). In phase 2, 6 other horses received MMF for 60 days (5 mg/kg, PO, q 24 h for 30 days and then 5 mg/kg, PO, q 48 h for an additional 30 days). RESULTS: Following IV (single-dose) or PO (single- or multiple-dose) administration, MMF was rapidly converted to mycophenolic acid. For single-dose PO administration, mean ± SD maximum plasma mycophenolic acid concentration was 1,778.3 ± 441.5 ng/mL at 0.71 ± 0.29 hours. For single-dose IV administration, mean systemic clearance and volume of distribution at steady state were 0.689 ± 0.194 L/h/kg and 1.57 ± 0.626 L/kg, respectively. Following single doses, mean terminal half-life was 3.99 ± 0.865 hours for IV administration and 4.02 ± 1.01 hours for PO administration. The accumulation index following long-term PO administration was 1.0 ± 0.002, and the terminal half-life was 4.59 ± 1.25 hours following the final dose on day 60. None of the horses developed abnormal clinical signs or had any consistently abnormal clinicopathologic findings. CONCLUSIONS AND CLINICAL RELEVANCE: Further investigation of the clinical efficacy of long-term MMF treatment of horses with autoimmune diseases is warranted.

Preclinical Efficacy and Anti-Inflammatory Mechanisms of Action of the Bruton Tyrosine Kinase Inhibitor Rilzabrutinib for Immune-Mediated Disease.

Bruton tyrosine kinase (BTK) is expressed in B cells and innate immune cells, acting as an essential signaling element in multiple immune cell pathways. Selective BTK inhibition has the potential to target multiple immune-mediated disease pathways. Rilzabrutinib is an oral, reversible, covalent BTK inhibitor designed for immune-mediated diseases. We examined the pharmacodynamic profile of rilzabrutinib and its preclinical mechanisms of action. In addition to potent and selective BTK enzyme and cellular activity, rilzabrutinib inhibited activation and inflammatory activities of B cells and innate cells such as macrophages, basophils, mast cells, and neutrophils, without cell death (in human and rodent assay systems). Rilzabrutinib demonstrated dose-dependent improvement of clinical scores and joint pathology in a rat model of collagen-induced arthritis and demonstrated reductions in autoantibody-mediated FcγR signaling in vitro and in vivo, with blockade of rat Arthus reaction, kidney protection in mouse Ab-induced nephritis, and reduction in platelet loss in mouse immune thrombocytopenia. Additionally, rilzabrutinib inhibited IgE-mediated, FcεR-dependent immune mechanisms in human basophils and mast cell-dependent mouse models. In canines with naturally occurring pemphigus, rilzabrutinib treatment resulted in rapid clinical improvement demonstrated by anti-inflammatory effects visible within 2 wk and all animals proceeding to complete or substantial disease control. Rilzabrutinib is characterized by reversible covalent BTK binding, long BTK residence time with low systemic exposure, and multiple mechanistic and biological effects on immune cells. Rilzabrutinib's unique characteristics and promising efficacy and safety profile support clinical development of rilzabrutinib for a broad array of immune-mediated diseases.

Preliminary study of the stability of dexamethasone when added to commercial veterinary ear cleaners over a 90 day period.

BACKGROUND: Topical corticosteroids are commonly used in the management of allergic otitis externa to diminish inflammation. A common strategy is to make compounded solutions of dexamethasone in ear cleaner. HYPOTHESIS/OBJECTIVES: The objective of this study was to determine the stability of dexamethasone when added to four commercial ear cleaners (ec): designated ecA, ecB, ecC and ecD. METHODS AND MATERIALS: Two concentrations (0.1 and 0.25 mg/mL) of dexamethasone were formulated for each cleaner solution from a 2 mg/mL solution and stored in the original manufacturers' bottles at two temperatures: room (22 ËšC) and refrigerated (4 ËšC). Samples were evaluated in triplicate, using liquid chromatography-tandem mass spectrometry at 10 time points over 90 days. The mean and standard deviation were calculated for each time point. RESULTS: A solution was considered stable if the dexamethasone value remained >90% of the target concentration. All dexamethasone solution values were stable to 90 days, except two solutions for ecA; the 0.25 mg/mL dexamethasone concentration was only stable to 14 (4 ËšC) and 21 days (22 ËšC). CONCLUSIONS AND CLINICAL IMPORTANCE: These results provide preliminary evidence in support of pharmaceutical stability data for dexamethasone when included in the above compounded solutions at the noted concentrations and temperatures.

Serum immunoglobulin E responses to aeroallergens in cats with naturally occurring airway eosinophilia compared to unaffected control cats.

BACKGROUND: Eosinophilic airway disease in cats is sometimes described as allergic in origin, but controversy exists in the documentation of allergy in cats and the utility of allergy testing for respiratory tract diseases. OBJECTIVE: To examine serum immunoglobulin E (IgE) response to aeroallergens in cats with airway eosinophilia. ANIMALS: Fifteen cats with idiopathic eosinophilic airway inflammation and 9 control cats. METHODS: Prospective, case-control study. Surplus serum from cats with airway eosinophilia documented by bronchoscopic bronchoalveolar lavage was submitted for IgE measurement using ELISA polyclonal antibody methodology. Responses for regional allergens (fungal organisms, weeds, grasses, trees, mites, insects) were assessed. Results were reported as ELISA absorbance units with scores 0 to 79 considered negative, scores between 80 and 300 considered intermediate, and scores >300 considered positive. RESULTS: Cats with airway eosinophilia had significantly more positive serum IgE responses (25/720) than did healthy controls (5/432, P = .02); however, the number of cats with positive IgE responses (5/15) did not differ from controls (1/9, P = .35). The allergen that most commonly resulted in positive serum IgE response in cats with airway eosinophilia was dust mite (n = 4) followed by 2 types of storage mites (n = 3 each). No control cat tested positive for these allergens. CONCLUSIONS AND CLINICAL IMPORTANCE: Serum IgE production against aeroallergens was found in some cats with eosinophilic airway inflammation, but the number of affected cats with positive results did not differ from controls. Further investigation in cats with eosinophilic, mixed, and neutrophilic airway disease in comparison to control cats is warranted.

Open trial of Bruton's tyrosine kinase inhibitor (PRN1008) in the treatment of canine pemphigus foliaceus.

BACKGROUND: Bruton's tyrosine kinase (BTK) is important in B-cell signalling. Efficacy has been reported for BTK inhibitors (BTKi) in human autoimmune diseases. Canine pemphigus foliaceus (cPF) is one of the most common canine autoimmune skin diseases. OBJECTIVES: To determine the safety and efficacy of the BTKi PRN1008 in the treatment of cPF. ANIMALS: Four privately owned dogs. METHODS AND MATERIALS: Four dogs diagnosed with PF were administered BTKi PRN1008. Initial dosages approximated to 15 mg/kg once daily, increased to twice daily if inadequate response was seen. Treatment continued for 20 weeks, attempting to decrease to every other day. Dogs were monitored with complete blood counts, serum biochemistry panels and urinalyses, and evaluated with a modified version of a validated human Pemphigus Disease Activity Index (cPDAI). Serum anti-desmocollin-1 (DSC-1) and desmoglein-1 (DSG-1) immunoglobulin (Ig)G titres were performed before and after the treatment period. Drug bound to target was measured in peripheral blood mononuclear cells (PBMC). RESULTS: All four dogs showed reduction in lesions and cPDAI score during the first two weeks of treatment. Three dogs continued to improve and sustained near complete remission by 20 weeks, at which point three responses were considered "good" and one "fair". Final daily dosages were in the range 17-33 mg/kg. Anti-DSC-1 IgG titre decreased dramatically in one dog, was undetectable in two and was uninterpretable in one dog. No dogs had detectable IgG to DSG1. A possible adverse event occurred in one dog. CONCLUSIONS AND CLINICAL IMPORTANCE: BTKi PRN1008 monotherapy may have some beneficial effects in some cases of cPF.

A case of atypical multifocal nodular eosinophilic dermatosis in a Labrador retriever dog.

BACKGROUND: A dog with gastrointestinal signs and a history of administration of multiple drugs developed acute multifocal to coalescing ulcerative nodules and a large plaque. OBJECTIVE: To describe abnormal nodular clinical lesions with an unexpected superficial and deep severe eosinophilic perivascular to interstitial inflammation. ANIMAL: A 7-year-old spayed female Labrador retriever METHODS AND MATERIALS: Blood tests, faecal and urinalysis, and abdominal radiographs were performed; skin biopsy samples were taken for cytological, culture and histopathological analyses. RESULTS: The blood tests, faecal, urinalysis and radiographs were within normal limits. Cytological results revealed inflammatory cells and cultures had no growth. Histopathological evaluation revealed dermal and subcutaneous oedema, mucin deposition and perivascular to interstitial inflammation predominated by eosinophils with occasional very small intralesional dense aggregates of eosinophils centred on collagen bundles, eosinophilic exocytosis and small eosinophilic pustules. Focal subepidermal fibrin exudation and haemorrhage resulted in epidermal detachment and ulceration. Clinical resolution of the dermatological and gastrointestinal signs was seen with the withdrawal of prior medications and administration of a tapering course of anti-inflammatory doses of prednisolone. CONCLUSIONS AND CLINICAL IMPORTANCE: To the best of the authors' knowledge, this is a novel nodular clinical and eosinophilic histopathological pattern combination. This case offers evidence of a spectrum of sterile eosinophilic dermatoses rather than multiple different disease processes.

A Missense Variant Affecting the C-Terminal Tail of UNC93B1 in Dogs with Exfoliative Cutaneous Lupus Erythematosus (ECLE).

Cutaneous lupus erythematosus (CLE) in humans encompasses multiple subtypes that exhibit a wide array of skin lesions and, in some cases, are associated with the development of systemic lupus erythematosus (SLE). We investigated dogs with exfoliative cutaneous lupus erythematosus (ECLE), a dog-specific form of chronic CLE that is inherited as a monogenic autosomal recessive trait. A genome-wide association study (GWAS) with 14 cases and 29 controls confirmed a previously published result that the causative variant maps to chromosome 18. Autozygosity mapping refined the ECLE locus to a 493 kb critical interval. Filtering of whole genome sequence data from two cases against 654 controls revealed a single private protein-changing variant in this critical interval, UNC93B1:c.1438C>A or p.Pro480Thr. The homozygous mutant genotype was exclusively observed in 23 ECLE affected German Shorthaired Pointers and an ECLE affected Vizsla, but absent from 845 controls. UNC93B1 is a transmembrane protein located in the endoplasmic reticulum and endolysosomes, which is required for correct trafficking of several Toll-like receptors (TLRs). The p.Pro480Thr variant is predicted to affect the C-terminal tail of the UNC93B1 that has recently been shown to restrict TLR7 mediated autoimmunity via an interaction with syndecan binding protein (SDCBP). The functional knowledge on UNC93B1 strongly suggests that p.Pro480Thr is causing ECLE in dogs. These dogs therefore represent an interesting spontaneous model for human lupus erythematosus. Our results warrant further investigations of whether genetic variants affecting the C-terminus of UNC93B1 might be involved in specific subsets of CLE or SLE cases in humans and other species.

Efficacy of a Bruton's Tyrosine Kinase Inhibitor (PRN-473) in the treatment of canine pemphigus foliaceus.

BACKGROUND: Bruton's tyrosine kinase (BTK) is important in B-cell signalling. Efficacy has been reported for BTK inhibitors (BTKi) in human autoimmune diseases. Canine pemphigus foliaceus (cPF) is the most common canine autoimmune skin disease. OBJECTIVES: To determine the safety and efficacy of a BTKi in cPF treatment. ANIMALS: Nine privately owned dogs. METHODS AND MATERIALS: Nine dogs diagnosed with PF were administered BTKi PRN473. Initial dosages were ≈15 mg/kg once daily, increased to twice daily if inadequate response was seen. Treatment continued for a maximum of 20 weeks, attempting decrease to every other day. Dogs were monitored with complete blood counts, serum biochemistry panels, urinalyses and evaluated with a modified version of a validated human Pemphigus Disease Activity Index (cPDAI). Anti-desmocollin-1 (DSC-1) and desmoglein-1 (DSG-1) immunoglobulin G (IgG) titres were performed before and after the treatment period. Drug bound to target was measured in peripheral blood mononuclear cells. RESULTS: All nine dogs showed reduction in lesions and cPDAI score during the first two weeks of treatment. At the end of the study, four responses were considered "good", two "fair", two "poor" and one dog withdrawn due to recurrence of a previously excised mast cell tumour. Four dogs continued to improve by Week 4; three sustained near complete remission by study's end. The anti-DSC-1 IgG titre decreased in three dogs, increased in two, was undetected in three and was not performed in the withdrawn dog. No dogs had detectable IgG to DSG1. Possible adverse effects occurred in three dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: Bruton's tyrosine kinase inhibitor monotherapy may have beneficial effects in some cases of cPF.

Skin disease in donkeys (Equus asinus): a retrospective study from four veterinary schools.

BACKGROUND: Donkeys are important throughout the world as work animals and occasionally as pets or a meat source. Most descriptions of skin disease in donkeys are reported in small case series, textbooks or review articles. HYPOTHESIS/OBJECTIVES: To document skin diseases and their prevalence in donkeys and to investigate predilections for the most common conditions. ANIMALS: Case populations at four veterinary schools totalling 156 donkeys. METHODS AND MATERIALS: A retrospective study was performed by searching computerized medical records, using the key word "donkey", at the School of Veterinary Medicine, University of California, Davis (UCD). Records of donkeys from the veterinary schools in Nantes, France; Utrecht, Netherlands and Ghent, Belgium were searched in a similar manner. The time periods included in the searches varied by institution. RESULTS: At UCD, 83 of 346 (24%) of donkeys had skin disease noted in their records. The most common diagnoses were insect bite hypersensitivity, sarcoid and habronemiasis. At Nantes, 36 of 144 (25%) had skin disease and the most common diagnoses were sarcoid and superficial pyoderma. At Utrecht 23 of 143 (16%) had skin disease and the most common diagnosis was dermatophytosis. At Ghent, 14 of 320 (4%) had skin disease and the most common diagnosis was sarcoid. CONCLUSIONS AND CLINICAL IMPORTANCE: Cutaneous conditions in donkeys are common. Age, sex and breed predisposition and the most common diagnoses varied with geographical location. Clinicians should include a dermatological examination regardless of the reason for presentation.

Companion rats (Rattus norvegicus) with cutaneous lesions: a retrospective study of 470 cases at two university veterinary teaching hospitals (1985-2018).

BACKGROUND: Rats are popular companion animals that are often presented to veterinarians for treatment of skin diseases. However, descriptions of dermatoses in rats have primarily been limited to case reports and text books. HYPOTHESIS/OBJECTIVES: To document skin diseases and their prevalence in companion rats examined in northern California, USA and Nantes, France and to investigate predilections for the most common conditions over a 33 year or 15 year period, respectively. ANIMALS: Four hundred and seventy rats from two hospital populations met the inclusion criteria. METHODS AND MATERIALS: A retrospective study was performed by searching computerized medical records of rats seen at the School of Veterinary Medicine at University of California, Davis (UCD), USA from 1 January 1985 to 1 January 2018 using the key words "skin" and "dermatitis". The medical records of rats presenting to Ecole Nationale Vétérinaire, Agroalimentaire et de l'Alimentation Nantes-Atlantique (ONIRIS), France from 1995 to 2016 were reviewed for evidence of skin disease. The presence of lesions as noted in the key search words for the UCD records were used as the inclusion criteria for both institutions. RESULTS: Of 494 rats examined at UCD, 231 (47%) had skin disease, with neoplasia the most common diagnosis. Of the 619 rats examined at ONIRIS, 239 (39%) had skin disease, with ectoparasitism being the most common diagnosis. CONCLUSIONS AND CLINICAL IMPORTANCE: Cutaneous conditions in companion rats are common. Clinicians should include a dermatological examination when examining these rodents, especially in regard to neoplasia, ectoparasites and pyoderma.

Companion hamsters with cutaneous lesions; a retrospective study of 102 cases at two university veterinary teaching hospitals (1985-2018).

BACKGROUND: Hamsters are popular companion animals which may present to veterinarians for treatment of skin diseases. Most descriptions of dermatoses in hamsters have primarily been in case reports and in text books. HYPOTHESIS/OBJECTIVES: To document skin diseases and their prevalence in companion hamsters examined in northern California, USA, and Nantes, France, and to investigate predilections for the most common conditions documented in medical records over a 33 year or 15 year period, respectively. ANIMALS: One hundred and one hamsters from two hospital populations. METHODS AND MATERIAL: A computerized search of medical records of all hamsters seen at the School of Veterinary Medicine at UC-Davis in California, USA, from 1 January 1985 to 1 January 2018, was performed using the key search words "skin" and "dermatitis". The medical records of all hamsters presenting to the Ecole Nationale Vétérinaire, Nantes, from 1 September 1998 to 1 December 2013, were reviewed for skin diseases. The presence of lesions noted in key search words for the California records were used as inclusion guidelines for both institutions. Cases of suspected mammary neoplasia were excluded. RESULTS: Of the 65 hamsters seen in California, 34 (54%) had skin disease; of a total of 164 hamsters in Nantes, 67 (41%) had skin disease. Nodules were the most common lesions noted by both institutions. CONCLUSIONS AND CLINICAL IMPORTANCE: Cutaneous conditions in companion hamsters are common. Clinicians should include a dermatological examination when examining these rodents.