Veterinary dermatology literature review: October 2026

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Summary. The October 2026 review focuses mainly on atopic dermatitis, antibiotic stewardship, chronic otitis and parasitic diseases. Two placebo-controlled trials show that fecal microbiota transplantation, added to usual treatment, and oral baicalin reduce the lesions of canine atopic dermatitis. Transplantation also reduces the need for symptomatic medication. The diagnosis of food allergy still relies on an elimination diet followed by oral challenge, because a systematic review finds no test able to replace it. Allergy also plays a part in infections: in diabetic patients, pyoderma is almost always accompanied by another disease, most often allergic dermatitis. To treat these infections, chlorhexidine remains active against staphylococci that are nonetheless multidrug-resistant, which supports topical treatment. In acute otitis, Nordic practitioners almost always give antibiotics topically when they prescribe them. When otitis becomes chronic or recurs, its cause should be sought: a fibroepithelial polyp to remove endoscopically, Aspergillus or a dermatophyte to culture, or Malassezia with reduced susceptibility to miconazole. Finally, two doses of oral lotilaner one month apart eliminate Lynxacarus radovskyi in cats, and a single dose of afoxolaner treats Cordylobia anthropophaga myiasis in dogs.

The October 2026 list brings together fifty-seven publications on the skin and ears of dogs and cats. Canine atopic dermatitis provides the largest share, with seven therapeutic trials, five of which included a placebo. Most of them assess adjunctive treatments, from the gut microbiota to cannabis oil. Otology forms the second group, from ear canal polyps to artificial intelligence applied to otoscopy. Two surveys measure what practitioners actually prescribe for skin and ear infections, and antimicrobial resistance recurs from one bacterial species to another. Parasitic diseases, skin oncology and diagnostic tools complete the month. Each article is presented below with its design, its sample size and what its results change in the consulting room, in eight categories.

Contents hide

1 1 Atopic dermatitis and allergology

1.1 1.1 Treatments for canine atopic dermatitis

1.2 1.2 Assessing atopic dermatitis

1.3 1.3 Allergen-specific immunotherapy

1.4 1.4 Food allergy

2 2 Bacterial infections and antibiotic stewardship

2.1 2.1 Pyoderma

2.2 2.2 Bacterial resistance and antibiotic stewardship

3 3 Fungal infections

4 4 Otology

4.1 4.1 Diagnosing otitis and its causes

4.2 4.2 Topical treatments

5 5 Parasitic diseases and leishmaniosis

6 6 Oncology and skin proliferations

6.1 6.1 Melanoma and squamous cell carcinoma

6.2 6.2 Mast cell tumors

6.3 6.3 Histiocytic proliferations

6.4 6.4 Cutaneous effects of treatments, papillomavirus and lymphoma

7 7 Non-infectious, genetic and behavioral dermatoses

8 8 Diagnostic tools: dermoscopy and endocrinology

9 References

1 Atopic dermatitis and allergology

1.1 Treatments for canine atopic dermatitis

Fecal microbiota transplantation, already used for digestive diseases, reduces the lesions of canine atopic dermatitis when added to usual treatment. Forty-six dogs were enrolled in a randomized, double-blind, placebo-controlled trial, and forty completed it, twenty in each group. Treated dogs received capsules of lyophilized microbiota every day for 90 days, plus three monthly rectal administrations, and symptomatic treatments remained allowed. CADESI-04 was lower with transplantation at month 2 (7 versus 16) and at month 3 (8 versus 15). Sustained responders, whose score had fallen by at least 50% at both visits, were more frequent with transplantation (35% versus 5%). The medication score was also lower at months 2 and 3. Transplanted dogs therefore needed fewer symptomatic treatments. Pruritus decreased in both groups, with no difference between them, and transplantation was well tolerated (Felten et al., 2026). The benefit thus concerns lesions and medication use, not pruritus.

Felten V, West EA, Martini F, Favrot C, Unterer S, Suchodolski J, et al. Faecal Microbiota Transplantation Reduces Lesion Severity and Medication Use in Canine Atopic Dermatitis: A Randomised, Placebo-Controlled, Double-Blinded Clinical Trial. Vet Dermatol. 2026 Oct;37(5):735-744. https://doi.org/10.1111/vde.70092

Oral baicalin, effective in several animal models of dermatitis, had never been evaluated in naturally occurring canine atopic dermatitis. Fifty-six dogs were randomized to receive baicalin or a placebo for 90 days. With baicalin, CADESI-04, pruritus, transepidermal water loss, total IgE and the quality-of-life score fell significantly at day 90 compared with baseline. CADESI-04 and pruritus were also significantly lower than with placebo. A good-to-excellent response was obtained in 82.1% of treated dogs, versus 35.7% with placebo, and the treatment was well tolerated (Qian et al., 2026). The dogs included had mild-to-moderate dermatitis, which limits the result to these forms.

Qian XL, Lu J, Lu W, Xu WX, Jiang ZH. Efficacy of Oral Baicalin in Canine Atopic Dermatitis: A Randomised Placebo Controlled Trial. Vet Dermatol. 2026 Oct;37(5):592-600. https://doi.org/10.1111/vde.70089

Adding a 0.015% triamcinolone acetonide spray to lokivetmab improves lesions within the first weeks. Twenty dogs with nonseasonal atopic dermatitis were randomized to lokivetmab alone or lokivetmab combined with the spray, in a four-week trial in which only the investigators were blinded. With the combination, CADESI-04 and its erythema score fell significantly at day 14 and day 28, and erythema was lower at day 28 than with lokivetmab alone. Pruritus decreased significantly in both groups (Banovic et al., 2026). Despite the small size of this preliminary trial, the spray appears useful as an adjunct during the initial phase of treatment.

Banovic F, Austel M, Johnson L, von Simson C. Comparative Efficacy and Safety of Adjunctive 0.015% Triamcinolone Acetonide Topical Spray With Lokivetmab Versus Lokivetmab Monotherapy as ‘Reactive Therapy’ for Canine Atopic Dermatitis: A Randomised, Single-Blinded, Controlled Preliminary Trial. Vet Dermatol. 2026 Oct;37(5):601-608. https://doi.org/10.1111/vde.70102

A cell therapy was compared with lokivetmab in mild-to-moderate atopic dermatitis. Thirty-two dogs were randomized two to one to a single intravenous injection of allogeneic adipose-derived mesenchymal stromal cells or three monthly subcutaneous injections of lokivetmab, in a single-blind study. At day 28, the primary endpoint, CADESI-04 and pruritus had fallen significantly in both groups, with no difference between them. Improvement was maintained up to day 84. In the cell group, scores were even lower at day 84 than at day 28. Two adverse events, one severe and one mild, occurred during administration of the cells, with no notable hematological or biochemical abnormality (Pasikowska et al., 2026). Intravenous injection therefore requires careful monitoring.

Pasikowska M, Ciszewska-Ceran J, Cekiera A, Gocek E, Grzesiak J, Reniewicz P, et al. Efficacy and Safety of Allogeneic Mesenchymal Stromal Cells Versus Lokivetmab in Mild-To-Moderate Canine Atopic Dermatitis: A Single-Blind Randomised Study. Vet Dermatol. 2026 Oct 22. Epub ahead of print. https://doi.org/10.1111/vde.70136

Three other supplements gave more modest results. The first, a postbiotic made of heat-killed Lactobacillus plantarum L-137, was given for 12 weeks to twelve dogs in a randomized, double-blind, placebo-controlled crossover trial, with oclacitinib still allowed. Pruritus decreased slightly more with the postbiotic, without a significant difference. Serum CCL17 chemokine decreased significantly with the postbiotic, whereas C-reactive protein increased significantly in the control group. CADESI-04 and the fecal microbiota did not change (Kiewsiri et al., 2026).

Kiewsiri C, Patumcharoenpol P, Kovitvadhi A, Chermprapai S. Efficacy of Heat-Killed Lactobacillus plantarum L-137 Supplementation in Treatment of Canine Atopic Dermatitis. Vet Dermatol. 2026 Oct 27. Epub ahead of print. https://doi.org/10.1111/vde.70139

The second, bovine colostrum, has immunomodulatory properties. It was added at 0.2% of dietary dry matter in twenty dogs, in a prospective, double-blind, placebo-controlled study. Four weeks of supplementation changed neither clinical nor immunological parameters (Schäfer et al., 2026).

Schäfer L, Büttner K, Paßlack N. Effects of a Dietary Supplementation of Bovine Colostrum in Dogs With Atopic Dermatitis. Vet Dermatol. 2026 Oct 8. Epub ahead of print. https://doi.org/10.1111/vde.70132

The third, a cannabis oil, was added to oclacitinib in sixteen dogs poorly controlled by that treatment. The sequence was fixed: oclacitinib alone, then placebo, then oil, then oil with an oclacitinib dose reduced by half. Fourteen dogs completed the study. CADESI-04 did not change, and pruritus did not differ between the placebo period and the oil period. Pruritus was, however, lower than at baseline with the oil, and it remained so after the dose reduction (Mariga et al., 2026). The authors consider that the oil contributed to pruritus control. The lack of difference with placebo and the fixed order of the periods nevertheless leave its own effect to be established. This last point is reasoning about the study design, not data reported by the authors.

Mariga C, da Silva FC, Schiefler OHM, Amazonas E, Mateus ALSS, Schmidt C, et al. Clinical observations during adjunctive Cannabis treatment and subsequent oclacitinib dose reduction in dogs with atopic dermatitis. Front Allergy. 2026 Oct 14;7:1852631. https://doi.org/10.3389/falgy.2026.1852631

Long-chain omega-3 fatty acids, EPA and DHA, are part of the nutritional management of atopic dermatitis. Thirty-five products on the Hungarian market were analyzed by gas chromatography: eight hypoallergenic veterinary diets, twenty-two commercial foods and five oral supplements. Combined EPA and DHA accounted on average for 0.94% of the fatty acids of hypoallergenic diets and 0.19% of those of commercial foods, versus 7.52% and 24.19% in the two marine-based supplements. In 29 of the 30 foods, the dominant omega-3 was alpha-linolenic acid. The omega-6 to omega-3 ratio varied widely from one supplement to another, up to 63.49 for a plant-based product (Tóth et al., 2026). Marine-based supplements therefore provided far more EPA and DHA than any of the foods analyzed.

Tóth Z, Fébel H, Wágner L, Buránszki B, Lajos A, Vida K, et al. Comparative Analysis of the Fatty Acid Profiles of Hypoallergenic Veterinary Diets, Commercial Dog Foods, and Oral Fatty Acid Supplements Available on the Hungarian Market. Vet Sci. 2026 Oct 16;13(10):1099. https://doi.org/10.3390/vetsci13101099

Outside atopic dermatitis, puppy microbiota was followed from birth to weaning in eighteen French Bulldogs delivered by cesarean section from four dams. Bacterial richness and diversity of the mouth and rectum increased significantly with age. Profiles converged toward those of the dams, especially after the transition from milk to solid food. The teat-skin microbiota was the main source early in life, before the dam’s oral and rectal microbiota took over (Cicirelli et al., 2026).

Cicirelli V, Peruzzo A, Burgio M, Bramante G, Fabbri G, Toscan E, et al. Evaluation of neonatal oral and rectal microbiota in dogs delivered by c-section, from birth to weaning. Vet J. 2026 Oct;319:106816. https://doi.org/10.1016/j.tvjl.2026.106816

1.2 Assessing atopic dermatitis

An owner-completed scale, the Dog-Orientated Severity of Atopy Scale (DOSAS), was adapted from a human eczema questionnaire to monitor the signs of atopic dermatitis and recurrent otitis. Its reliability and validity exceeded the accepted thresholds for this type of tool. It tracked changes in CADESI-04 and in the pruritus scale well, and those in the OTIS-3 otitis score less well (Harvey et al., 2026). It complements the clinical examination with the owner’s perspective, and owners thus take a more active part in monitoring their dog.

Harvey N, Watson A, Laxalde J, England G, Gow D. Development and Validation of a New Online Tool for Monitoring Clinical Signs of Canine Atopic Dermatitis. Vet Dermatol. 2026 Oct 23. Epub ahead of print. https://doi.org/10.1111/vde.70133

A narrative review, supported by the opinion of a panel of dermatologists, examines the design of clinical trials in canine atopic dermatitis. The sources of error to control are numerous: exposure to food and environmental allergens, season, fleas, bacterial and fungal infections, concomitant treatments and the length of treatment-free periods before enrollment. Registration trials mostly enrolled treatment-naïve dogs with mild-to-moderate disease. The review discusses the trade-off between the rigor of these trials and the applicability of their results to other dogs (Klotsman et al., 2026). It therefore argues for protocols adapted to the phenotype studied rather than a uniform method.

Klotsman M, Sagiv SK, Anderson WH, Santoro D. Canine atopic dermatitis clinical trials: study design and methodological considerations. Front Vet Sci. 2026 Oct 9;13:1878714. https://doi.org/10.3389/fvets.2026.1878714

1.3 Allergen-specific immunotherapy

Rush immunotherapy compresses the induction phase into a single day of increasing doses. Its safety was studied retrospectively in forty-seven cats with feline atopic skin syndrome, in several centers, between 2019 and 2024. Three cats (6.4%) had adverse events: tachypnea, behavioral distress and increased pruritus. The protocol was discontinued in one cat. All then received maintenance immunotherapy without recurrence of these events (Wirkkala et al., 2026). Performed under clinical monitoring, rush induction therefore appears well tolerated in cats.

Wirkkala A, Rosenkrantz W, Mendelsohn C, Griffin C, Schaufele S, Burrows M. Retrospective Review of Rush Allergen-Specific Immunotherapy Safety in Cats With Atopic Skin Syndrome. Vet Dermatol. 2026 Oct;37(5):729-734. https://doi.org/10.1111/vde.70108

Allergen-specific immunotherapy is the only treatment that targets the mechanism of the disease, but owner persistence remains a challenge. This persistence was analyzed with a questionnaire based on the Health Belief Model, among owners of animals treated in four dermatology practices between 2020 and 2024. Owners who considered the disease severe, believed the treatment effective or felt able to administer it renewed the treatment more often. Cost and administration difficulties were the main barriers (Williams et al., 2026). Explaining the disease, the value of treatment and how to administer it could therefore help owners continue.

Williams C, Milum AW, Andritsch S, von Fricken ME, Painter M. Applying the Health Belief Model to Identify Factors Associated With Owner Persistence to Allergen-Specific Immunotherapy. Vet Dermatol. 2026 Oct;37(5):713-721. https://doi.org/10.1111/vde.70072

1.4 Food allergy

A systematic review confirms that no test replaces the elimination diet followed by an oral food challenge for diagnosing food allergy in dogs. Fifty-nine studies published between 1986 and 2025 in sixteen countries were included, too heterogeneous for a meta-analysis. Serum or salivary IgG and IgE assays correlated poorly with clinical outcome. Among skin tests, the standardized patch test performed best, thanks to a high negative predictive value, but its practical value remains limited. Cellular tests, such as lymphocyte proliferation, agreed best with the oral challenge and open a line of research (Morales-Romero et al., 2026).

Morales-Romero R, Gonzalez-Dominguez MS, Roldán-Villalobos W, Correa-Valencia NM. Systematic review supports the idea that no alternative test presently replaces elimination diet test and oral food challenge to diagnose canine adverse food reactions. J Am Vet Med Assoc. 2026 Oct 23:1-10. Epub ahead of print. https://doi.org/10.2460/javma.26.06.0456

In Malaysia, Singapore and Indonesia, chicken is the food allergen most often involved. Forty-nine dogs with nonseasonal pruritus were followed prospectively between 2022 and 2024. All relapsed on challenge after an elimination diet. Chicken was involved in 65% of dogs in Malaysia, 31% in Singapore and 63% in Indonesia. Pedal pruritus, otitis or both affected 68% of dogs (Hernadi and Siew, 2026). These signs therefore warrant investigation of food allergy once other pruritic dermatoses have been ruled out.

Hernadi H, Siew HH. Clinical Signs and Offending Food Allergens in Canine Cutaneous Adverse Food Reactions in Malaysia, Singapore and Indonesia: A Prospective Study. Vet Dermatol. 2026 Oct;37(5):722-728. https://doi.org/10.1111/vde.70093

2 Bacterial infections and antibiotic stewardship

2.1 Pyoderma

The severity of superficial pyoderma had no validated scale. Sixty dogs with papules, pustules, epidermal collarettes or yellow crusts were examined prospectively by six clinicians, at baseline and at up to two follow-up visits. Recognition of lesion types and categorical severity grading agreed poorly from one clinician to another. Counting papules and pustules, and measuring the areas of confluent lesions, collarettes and crusts, were on the other hand reproducible, between clinicians as well as within the same clinician. The model derived from these measurements estimates severity on a continuous scale from 0 to 100, with a mean error of about nine points per case (Pinto et al., 2026). It still needs to be validated.

Pinto M, Grass D, Herrmann I. Standardising Assessment of Superficial Pyoderma in Dogs: Proposal of a Severity Score. Vet Dermatol. 2026 Oct;37(5):609-619. https://doi.org/10.1111/vde.70086

In diabetic patients, pyoderma is almost always accompanied by another disease. At two US universities, cytologically confirmed pyoderma was found between 2019 and 2022 in 61 of 805 diabetic dogs (7.6%) and in 15 of 372 diabetic cats (4.0%). Only two of these dogs and one of these cats had no concurrent disease. Allergic dermatitis was the most frequent, present in 70.5% of dogs and 73.3% of cats with pyoderma, and it was associated with a higher risk of pyoderma. The West Highland White Terrier also had an increased risk. Pyoderma due to diabetes alone therefore concerned only 0.25% of diabetic dogs and 0.27% of diabetic cats (Wixon et al., 2026).

Wixon V, Pieper JB, Bachtel J. The Role of Comorbidities in Pyoderma Among Canine and Feline Diabetic Patients. Vet Dermatol. 2026 Oct 7. Epub ahead of print. https://doi.org/10.1111/vde.70131

Chlorhexidine remains effective against canine staphylococci, even multidrug-resistant ones. One hundred forty-five staphylococcal isolates, including Staphylococcus pseudintermedius and S. schleiferi, were collected in Korea from dogs with pyoderma and from healthy dogs. Of these, 64.1% were multidrug-resistant. Minimum inhibitory concentrations (MICs) of chlorhexidine digluconate ranged from 0.25 to 2 µg/mL, with no difference between multidrug-resistant and other isolates, and remained far below the concentrations used clinically. Antiseptic resistance genes were rare: qacA/B in 4 isolates, qacG in 13 and smr in 10. Isolates carrying both qacA/B and smr had slightly higher MICs, but they were too few to draw conclusions (Kim et al., 2026b). Monitoring of susceptibility therefore remains advisable.

Kim MS, Kang JH, Lim JH, Yang SJ, Hwang CY. Antimicrobial resistance and chlorhexidine susceptibility in canine staphylococcal isolates from dogs with pyoderma and clinically healthy dogs. J Vet Med Sci. 2026 Oct 21. Epub ahead of print. https://doi.org/10.1292/jvms.26-0373

2.2 Bacterial resistance and antibiotic stewardship

Sporotrichosis wounds in cats become infected with staphylococci that are sometimes methicillin-resistant. In Brazil, 233 wound samples from 203 cats treated for sporotrichosis and showing signs of secondary infection were analyzed. A staphylococcus was isolated from 67% of samples, mainly S. aureus (42.3%) and S. felis (25.6%). Resistance was frequent to penicillin (51.9%), erythromycin (28.8%) and clindamycin (19.2%), whereas most isolates remained susceptible to chloramphenicol, ciprofloxacin and nitrofurantoin. Among the isolates, 24% were multidrug-resistant and twelve (7.7%) methicillin-resistant, including four S. pseudintermedius and one S. aureus. This S. aureus belonged to a lineage widespread worldwide and often associated with nosocomial infections in humans (Campos et al., 2026). Feline sporotrichosis, already zoonotic, therefore also raises a public health question of antimicrobial resistance.

Campos JVF, de Souza TGV, de Souza BM, de Melo IMS, de Castro YG, Rosa JCC, et al. Antimicrobial resistance in Staphylococcus spp. isolated from sporotrichosis-affected cats in Brazil: Detection of MRSP and MRSA. Vet Microbiol. 2026 Oct;321:111195. https://doi.org/10.1016/j.vetmic.2026.111195

In dogs, Proteus mirabilis also carries extended-spectrum beta-lactamases. Six hundred sixty-seven isolates were collected in Korea between 2018 and 2024 from the skin and ear, feces, and urinary and reproductive tracts of sick dogs. Just over a quarter (27.3%) were multidrug-resistant. Thirty-eight isolates carried extended-spectrum beta-lactamase or AmpC cephalosporinase genes, mainly blaCMY-2 (65.8%) and blaCTX-M variants. Clone ST135 predominated (39.5%) and concentrated the most marked multidrug-resistance profiles (Hwang et al., 2026). The authors regard it as a high-risk clone, endemic in the Korean canine population, and call for joint surveillance of animals and humans.

Hwang YJ, Lee YH, Ali MS, Choi JH, Park SC, Moon BY, et al. Antimicrobial resistance and molecular characterization of extended-spectrum β-lactamase/AmpC β-lactamase-producing Proteus mirabilis isolates from companion dogs in South Korea (2018-2024). Am J Vet Res. 2026 Oct 28:1-9. Epub ahead of print. https://doi.org/10.2460/ajvr.26.07.0292

Culture and susceptibility testing take at least two days, which delays the choice of antibiotic. A hybrid workflow was evaluated on 60 interpretable plates from skin, ear and urine infections in dogs and cats. The sample is inoculated in the clinic onto a chromogenic agar, where antibiotic disks are placed. After 16 to 20 hours of incubation, the plate is photographed and read remotely by an expert. Identification of the primary bacterium agreed with the laboratory in 83.9% of cases, and in all cases when staphylococcal species were grouped. Secondary bacteria, masked by the dominant bacterium, were identified in the same way in only 16.7% of cases. Susceptibility testing agreed in 93.6% of cases, with a sensitivity of 91.9% for detecting resistance (Cugmas et al., 2026). This early result must be confirmed by the laboratory. The proportion of samples actually suitable was not measured either.

Cugmas B, Štruc E, Vesel U, Viškere D, Kulasalu L, Sapugahawatte DN. Clinical Evaluation of a Centralized In-Clinic Direct Culture and Antimicrobial Susceptibility Testing Workflow for Canine and Feline Skin, Ear, and Urine Infections. Antibiotics (Basel). 2026 Oct 13;15(10):1016. https://doi.org/10.3390/antibiotics15101016

In the United States, more than half of the animals seen in referral dermatology receive an antimicrobial. A point-prevalence survey conducted in August 2023 in 22 practices covered 550 animals, 479 dogs and 71 cats, the first twenty-five seen in each. An antimicrobial was prescribed in 54.9% of cases and an antiseptic in 62.7%. Third-generation cephalosporins accounted for 43.9% of systemic antibiotics given to dogs. For otitis with bacteria only or yeast only, 36.4% of the topical products prescribed combined an antibiotic and an antifungal. Cytology had been performed in 86.3% of conditions treated with an antimicrobial, bacterial culture in only 15.3% (Santoro et al., 2026). The authors see room to reduce broad-spectrum systemic antibiotics in favor of topical treatments.

Santoro D, Bollig ER, Granick JL. Prevalence of Antimicrobial Use in Small Animal Dermatology Referral Practices in the United States. Vet Dermatol. 2026 Oct;37(5):581-591. https://doi.org/10.1111/vde.70087

In Sweden, Finland and Norway, acute otitis externa in dogs is most often treated without antibiotics. A point-prevalence survey conducted in spring 2024 in the clinics of a single group collected 1,060 cases of acute otitis lasting four weeks or less. An antibiotic was prescribed in 18% of cases, almost always topically: the systemic route was used only six times. Prescription reached 28% in Norway and 29% in Finland, versus 2% in Sweden. Polymyxin B was the most used antibiotic. Antibiotic use depended more on cytology, especially the presence of neutrophils and rods, than on clinical appearance. Glucocorticoids were prescribed in 94% of cases and an ear cleaner in 89% (Saarinen et al., 2026).

Saarinen K, Ljungquist D, Seppänen R, Kaimio M, Andersson AM. Treatment Choices for Acute Canine Otitis Externa in Sweden, Finland and Norway: A Comparative Study With a Focus on Antibiotic Use. Vet Dermatol. 2026 Oct;37(5):806-817. https://doi.org/10.1111/vde.70094

3 Fungal infections

Malassezia pachydermatis can resist miconazole. At a referral center, yeast otitis persisted more often after miconazole treatment, which led to the study of isolates from 16 ears of 11 dogs. These isolates fell into three clades. Most mutations in the ERG11 gene, which encodes the azole target lanosterol 14α-demethylase, were clade-specific and did not change susceptibility. Reduced susceptibility was linked to substitutions of amino acid A302, located in the azole-binding site. Less susceptible isolates were easy to find, which suggests that miconazole resistance exists in routine patients (Belcher et al., 2026). Longer-tailed azoles make additional contacts with the enzyme and should therefore be more active against these strains. Responsible antifungal use remains necessary to prevent resistance to all azoles.

Belcher CM, Souza CP, McGuire E, Hung CC, Tyndall JDA, Hoyer LL. Phylogenetic and Structural Analysis of Miconazole Susceptibility in Malassezia pachydermatis Isolates From Dogs With Otitis Externa. Vet Dermatol. 2026 Oct;37(5):620-629. https://doi.org/10.1111/vde.70059

Otitis externa caused by fungi other than Malassezia is uncommon. Seventeen cases, four dogs and thirteen cats, were reviewed retrospectively in Chinese dermatology services between 2022 and 2024. Aspergillus was isolated from thirteen animals, three dogs and ten cats, and Microsporum canis from one dog and two cats. One cat had M. canis in one ear and Aspergillus in the other. The most frequent signs were excessive cerumen and pruritus. Of sixteen treated animals, thirteen received an oral and topical antifungal, three an oral antifungal alone (Tang et al., 2026). In chronic or recurrent otitis, cytology of the exudate and fungal culture therefore help avoid missing Aspergillus or a dermatophyte.

Tang X, Luo X, Liu X, Zhao B, Wang F, Han HS. Seventeen Cases of Fungal Otitis Externa in Dogs and Cats. Vet Dermatol. 2026 Oct 28. Epub ahead of print. https://doi.org/10.1111/vde.70140

In Persian cats, the skin microbiota does not appear to determine the clinical expression of dermatophytosis. Forty-five cats were compared: fifteen Persians with lesions and a positive culture, fifteen Persians without lesions but with a positive culture, and fifteen healthy domestic shorthair cats with a negative culture. Hair and scale samples, collected with a carpet square and a toothbrush, were analyzed by sequencing of fungal and bacterial communities. The composition of these communities was similar in cats with and without lesions, whatever the sampling method, and the relative abundance of Microsporum did not differ (Santana et al., 2026). Other factors, such as the host immune response, therefore seem to determine the outcome.

Santana AE, Torres SMF, Costa MO. Skin Commensal Microbiota Does Not Influence the Clinical Course of Dermatophyte Infection in Persian Cats. Vet Dermatol. 2026 Oct;37(5):700-712. https://doi.org/10.1111/vde.70058

4 Otology

4.1 Diagnosing otitis and its causes

Ear cytology follows the severity of otitis, especially when the infection is bacterial. In 318 dogs seen in referral dermatology and reviewed retrospectively, the clinical OTIS3 score, graded from 0 to 12, was moderately correlated with the total cytology score (coefficient of 0.45). This clinical score increased significantly with the burden of cocci and rods, but not with that of Malassezia, and it was higher when neutrophils were present (Shin et al., 2026). Read together with OTIS3, cytology therefore serves for both assessment and monitoring of otitis.

Shin ES, Kang SY, Kim MS, Hwang CY. Associations Between Otic Cytological Findings and Clinical Severity by Pathogen Group in Canine Otitis Externa: A Retrospective Study of 318 Cases. Vet Dermatol. 2026 Oct;37(5):858-864. https://doi.org/10.1111/vde.70107

Artificial intelligence does not yet perform as well as the veterinarian in otoscopy. Four detection models were tested on 300 otoscopic images they had never seen: 100 healthy canals, 100 cases of otitis and 100 masses. The best one, trained on the largest image set without duplicates, reached 66.3% agreement with the reference. Its sensitivity was 90% for the healthy canal, 59% for otitis and 50% for masses. The six veterinarians evaluated on the same images did better, with a median agreement of 77.2%, and the referral clinician achieved the highest concordance (McInnis et al., 2026). The model therefore remains a decision-support tool, not a substitute for the clinician.

McInnis M, Liu CC, Arbona V, Apostolopoulos N. External Validation of a Custom-Trained Artificial Intelligence Model for Canine Ear Canal Disease and Comparison With Veterinary Professionals. Vet Dermatol. 2026 Oct;37(5):850-857. https://doi.org/10.1111/vde.70105

Fibroepithelial polyps of the canine ear canal were poorly known. Seventeen polyps were described retrospectively in fourteen dogs, all of brachycephalic breeds, mostly French Bulldogs. Twelve dogs had a history of chronic recurrent otitis externa and ten had atopic dermatitis. Video-otoscopy always showed a pedunculated mass, and CT detected 15 of 17. All were removed endoscopically, with a snare or grasping forceps, and a second procedure was needed in two dogs to remove residual fragments. On histology, each mass had a broad fibrous core on a narrow stalk, and thirteen contained bony trabeculae. Thirteen of the fourteen dogs did not relapse during a follow-up of 1 to 80 months (Mendes et al., 2026). Removing these polyps could therefore be decisive in resolving some chronic recurrent otitis.

Mendes C, Berto L, Costa A, Nordio L, Bertolini G, De Lucia M. Fibroepithelial Polyps of the Ear Canal in Dogs: A Retrospective Analysis of 17 Cases. Vet Dermatol. 2026 Oct;37(5):841-849. https://doi.org/10.1111/vde.70103

In young cats, cone beam computed tomography, or CBCT, clearly shows the bony changes associated with inflammatory polyps. The studies of 38 cats with polyps were reviewed retrospectively. Performed without contrast and read by a board-certified radiologist, they made it possible to recognize normal and affected structures of the middle and inner ear. The most frequent changes were thickening of the tympanic bulla (65.7%), widening of the auditory tube (52.6%) and lysis of the cochlea and ossicular chain (7.8%) (Colón Rodríguez et al., 2026). CBCT can therefore serve as a first-line imaging test when a polyp is suspected.

Colón Rodríguez A, Campanale DN, Sarment D, Canfield MS. Osseous Changes in Young Cats With Inflammatory Aural Polyps: A Cone Beam Computed Tomography Analysis. Vet Dermatol. 2026 Oct;37(5):833-840. https://doi.org/10.1111/vde.70100

In cats with ceruminoliths, the tympanic membrane is often damaged. Thirty-one cats were reviewed retrospectively between 2011 and 2024. Twenty-six underwent otoendoscopy-guided lavage under general anesthesia combined with medical treatment, and five received medical treatment alone, most often a ceruminolytic and systemic corticosteroids for 2 to 7 days. The tympanic membrane was perforated in ten cats and thickened or discolored in five. At the final recheck, four cats still had a scar or irregularity of the tympanic membrane, and one perforation persisted. At the first follow-up, 55% of cats were free of ceruminoliths. At the last one, 65% remained recurrence-free (Moreira André et al., 2026). Because ceruminoliths recur, an underlying predisposing factor should be sought and these cats followed over the long term.

Moreira André M, Prélaud P, Briand A. Management and Clinical Outcomes of Cats With Ceruminoliths: A Retrospective Study of 31 Cases. Vet Dermatol. 2026 Oct;37(5):827-832. https://doi.org/10.1111/vde.70065

4.2 Topical treatments

Lactobacilli-based ear drops were tested in non-infected erythroceruminous otitis. Thirty-seven dogs received them every other day for 28 days, in an open-label multicenter study. The OTIS3 score fell on average from 5.11 to 1.66 and pruritus from 4.93 to 2.09, two significant decreases, regardless of concomitant treatments and of the type of initial microbial overgrowth. According to their owners, quality of life improved in 80% of dogs (Carrasco et al., 2026). These drops can serve as an adjunctive treatment, but the study was open-label and had no control group.

Carrasco I, Homedes J, Arcas A, Beasley S, Salichs M. Clinical Efficacy of Probiotic-Based Ear Drops Containing Lactobacilli in Canine Erythroceruminous Otitis Externa: An Open Label, Multicentre Study. Vet Dermatol. 2026 Oct;37(5):818-826. https://doi.org/10.1111/vde.70097

Cold atmospheric plasma was compared with the usual topical treatment in acute otitis externa, each ear of the same dog receiving a different treatment. Twenty-two dogs with bilateral otitis received in one ear a topical product combining an antibiotic, an antifungal and a corticosteroid, twice daily for ten days. The other ear received cold plasma, twice (day 0 and day 5) in one group and four times (days 0, 3, 6 and 9) in the other. OTIS-3 and cytology scores fell significantly with plasma, as with the usual treatment. Almost all investigators and owners rated the response as good to excellent, with no adverse effects (Bakır et al., 2026). Cold plasma could therefore serve as an adjunctive treatment in acute otitis.

Bakır A, Nett-Mettler CS, Ulutas B. An Open-Label Split-Body Clinical Trial Evaluating Therapeutic Efficacy and Safety of Cold Atmospheric Plasma in Canine Acute Otitis Externa. Vet Dermatol. 2026 Oct;37(5):797-805. https://doi.org/10.1111/vde.70063

5 Parasitic diseases and leishmaniosis

Oral lotilaner eliminates Lynxacarus radovskyi, a mite that lives on the hair of cats. Twenty naturally infested cats were allocated to a group treated with lotilaner on day 0 and day 30 and an untreated control group, ten cats each, in a prospective parallel-group study. The parasitological score, determined weekly by trichogram at three sites, fell significantly from day 7, whereas control cats remained infested. Mite count reduction reached 98.0% at day 35 and 100% from day 42, after the second dose. Pruritus and lesions also decreased significantly (da Mota de Magalhães et al., 2026).

da Mota de Magalhães Y, Marques DM, Christ LX, Campos DR, Fernandes JI. Efficacy of Oral Lotilaner in Controlling Clinical Signs in Cats Naturally Infested With Lynxacarus radovskyi. Vet Dermatol. 2026 Oct 30. Epub ahead of print. https://doi.org/10.1111/vde.70141

A single dose of afoxolaner treats furuncular myiasis caused by Cordylobia anthropophaga, a sub-Saharan African fly that also parasitizes humans. In Kenya, 104 naturally infested dogs were randomized to a treated group (53 dogs) or an untreated control group (51 dogs), in a blinded study. Compared with controls, efficacy reached 94% at day 15 and 100% at day 30. Treated dogs improved from the first recheck, whereas infestation persisted in controls. No examined puppy born to or nursed by a treated dam was infested, up to 4 weeks after birth for those exposed during pregnancy and up to 11 weeks of age for those exposed during lactation (Mihalca et al., 2026). This indirect protection of puppies still needs confirmation.

Mihalca AD, Mitrea IB, Rabei ŞO, Lolokote S, Modrý D, Beugnet F. Efficacy of afoxolaner (NexGard®) for the treatment of myiasis caused by the zoonotic tumbu fly, Cordylobia anthropophaga, in domestic dogs under field conditions. Vet Parasitol. 2026 Oct;347:110866. https://doi.org/10.1016/j.vetpar.2026.110866

A single application of a topical combination of fipronil, permethrin, piperonyl butoxide and pyriproxyfen was followed in Mexico in 44 naturally infested dogs. The 18 dogs carrying fleas only had none left at day 15 or day 30. Of the 11 dogs carrying ticks only, none had any left at day 15, and one carried ticks at day 30. In mixed infestations, three dogs out of fifteen remained infested at day 15, and two at day 30. Lesion and pruritus scores also decreased, with no adverse effects (Romero-Núñez et al., 2026). The study, without a control group and based on non-validated scores, remains descriptive and does not establish a treatment effect.

Romero-Núñez C, Heredia-Cárdenas R, Flores-Ortega A, Bautista-Gómez LG, Gaxiola-Camacho SM, Torres-Cruz JD. Changes in flea and tick infestation following topical fipronil, permethrin, piperonyl butoxide, and pyriproxyfen in naturally infested dogs: an exploratory uncontrolled field study. Front Vet Sci. 2026 Oct 13;13:1903878. https://doi.org/10.3389/fvets.2026.1903878

In Turkey, in the Black Sea region, skin abnormalities were associated with positive leishmaniosis tests in shelter dogs. Two hundred stray dogs were examined and tested by blood smear and by rapid serological test. Nine of them (4.5%) met the combined definition of positivity. Skin abnormalities were present in 15% of dogs, and their presence was significantly associated with positivity. The four smear-positive dogs all had abnormal skin (Civek and Özkan, 2026). The authors present these results as exploratory, because confirmation of the diagnosis and of the lesions was limited.

Civek E, Özkan Ö. Clinical and dermatological findings associated with Leishmania spp. test-positivity in shelter dogs of Kastamonu, Black Sea region of Türkiye: an exploratory cross-sectional study. Acta Trop. 2026 Oct 20;283:108376. Epub ahead of print. https://doi.org/10.1016/j.actatropica.2026.108376

In a cat infected with Leishmania amazonensis, skin nodules were examined with five stains: hematoxylin and eosin, PAS, fast green, Fontana-Masson and Mallory’s trichrome. The dermis showed a moderate lymphoplasmacytic infiltrate and numerous macrophages with cytoplasm filled with amastigotes. Hematoxylin and eosin best distinguished amastigotes from surrounding tissue. Fast green and Mallory’s trichrome allowed reasonable differentiation, and Fontana-Masson proved of little use (Assis et al., 2026). This single case is a reminder that cutaneous leishmaniosis, a zoonosis, can also affect cats.

Assis CS, Moron SE, Nogueira AFS, Barbosa SM, Silva GML, Lima LBD, et al. Histopathological findings and staining performance in cutaneous nodules from a cat with Leishmania amazonensis infection. Vet Parasitol. 2026 Oct;347:110868. https://doi.org/10.1016/j.vetpar.2026.110868

6 Oncology and skin proliferations

6.1 Melanoma and squamous cell carcinoma

In canine melanoma, tumor-associated lymphocytic inflammation is accompanied by better survival. One hundred seventeen melanomas were studied, 74 from the oral cavity or digits and 43 cutaneous. Most showed little inflammation, whatever their site. When present, inflammation was mild, mainly lymphocytic, more frequent in large tumors and associated with longer survival. It was also more frequent in oral and digital tumors. The most extensive and aggressive tumors contained more CD4+ and FoxP3+ lymphocytes (Vieira-Filho et al., 2026). These tumors therefore elicit an immune response, but with a regulatory profile.

Vieira-Filho CHC, Veloso ES, Santos JN, Ferreira E, Damasceno KA, Portela RW, et al. Tumor-infiltrating lymphocytes and Treg cells in canine melanomas: Site-specific prognostic implications. Vet Immunol Immunopathol. 2026 Nov;301:111226. https://doi.org/10.1016/j.vetimm.2026.111226

In Australia, the distribution of canine cutaneous squamous cell carcinoma is consistent with chronic ultraviolet exposure. A matched case-control study included 295 histologically confirmed cases and 1,180 controls between 2014 and 2023. Cases were concentrated in Queensland (39.7%) and New South Wales (39.3%), especially along the coast, and 54.9% of tumors were located caudal to the thorax. Dogs aged 7 to 11 years and those aged 12 years and older had a higher risk than dogs aged 2 to 6 years (odds ratios of 7.4 and 4.8). Risk was also higher in Dalmatians, bulldogs, Staffordshire terriers and schnauzers than in mixed breeds. It was higher, finally, in dogs with a white or mostly white coat than in dogs with a dark coat (Zhang et al., 2026).

Zhang JJ, Dejene H, Granados-Soler JL, Henning J, Allavena R. Demographic and environmental factors associated with canine cutaneous squamous cell carcinoma development in Australia: a retrospective matched case-control analysis. Vet Res Commun. 2026 Oct 24;51(1):20. https://doi.org/10.1007/s11259-026-11595-5

6.2 Mast cell tumors

Early neutering is associated with a more frequent diagnosis of mast cell tumor, with no effect on survival. Among 56,254 dogs seen at a university hospital between 2015 and 2024, 313 had a mast cell tumor. These 313 dogs were compared with tumor-free controls matched by age, in a retrospective study. Neutering before 24 months of age was associated with higher odds of diagnosis than remaining intact, unlike neutering after 24 months. Medium or large body size, overweight and certain breeds, especially American Pit Bull Terriers and Boxers, were also associated with diagnosis. Survival depended on histological grade and tumor size, not on neutering (da Silva et al., 2026).

da Silva EMG, Mantovani MM, Silva MJB. Clinical features, survival, and associated factors for canine mast cell tumors: The role of neutering. Vet J. 2026 Oct 11;320:106929. Epub ahead of print. https://doi.org/10.1016/j.tvjl.2026.106929

Intralesional triamcinolone injection before excision of a mast cell tumor is not accompanied by more frequent wound complications. Sixty-nine dogs with 78 cutaneous or subcutaneous mast cell tumors, injected within 30 days before surgery, were reviewed retrospectively. Surgical site complications occurred in 25% of tumors, minor in 90% of cases. They affected no tumor that had received two or more injections, versus 36% of those that had received only one. Neither the dose, nor the interval before surgery, nor tumor characteristics, nor bandaging were associated with them. Among tumors with a recorded response, 65% decreased in size, by a median of 40% (Gruber et al., 2026). The study included only injected dogs: the complication rate is considered acceptable, but without comparison with non-injected dogs.

Gruber DR, Doornink MT, Urie BK. Neoadjuvant intralesional triamcinolone is not associated with increased incidence of surgical site complications in dogs with cutaneous and subcutaneous mast cell tumors. J Am Vet Med Assoc. 2026 Jul 8;264(10):1-7. https://doi.org/10.2460/javma.26.04.0311

6.3 Histiocytic proliferations

Cutaneous histiocytoma mostly affects young dogs, with breed-specific locations. Three hundred fifty-nine histologically confirmed histiocytomas were collected by a Portuguese laboratory between January 2020 and January 2022. Nearly half of the dogs (48.8%) were two years old or younger, and 58.5% were males. The annual incidence in the Lisbon and Setúbal region was 4.0 per 10,000 dogs. Risk was highest in French Bulldogs (relative risk of 11.5) and Boxers (relative risk of 8.3), compared with mixed breeds (De Moura et al., 2026).

De Moura C, Pinello K, Catarino J, Niza-Ribeiro J, Santos J, Faísca P. Epidemiology of Canine Cutaneous Histiocytoma: Insights From Age and Topographic Clustering. Vet Dermatol. 2026 Oct;37(5):780-787. https://doi.org/10.1111/vde.70068

In Golden Retrievers, immunohistochemistry helps distinguish cutaneous reactive histiocytosis from granulomatous diseases. Eleven Golden Retrievers were studied on paraffin-embedded biopsies, with a broad histiocytic marker, Iba1, and a cocktail of antibodies against macrophage markers (CD11b, CD68, CD163, CD14 and CD16). Histiocytic cells were diffusely labeled by Iba1, but the cocktail labeled only a few scattered ones, which points to dendritic cells rather than macrophages (Albanese et al., 2026). Combining the two markers therefore helps separate reactive histiocytosis from macrophage-rich granulomatous diseases.

Albanese F, Lazzarini G, Orlandi M, Pirone A, Miragliotta V, Mazzoni E, et al. Cutaneous Reactive Histiocytosis in Golden Retrievers: An Immunohistochemical Approach. Vet Dermatol. 2026 Oct;37(5):745-751. https://doi.org/10.1111/vde.70104

6.4 Cutaneous effects of treatments, papillomavirus and lymphoma

With lapatinib, cutaneous adverse events accompany a better response to treatment. In dogs with urothelial carcinoma, reviewed retrospectively, these events occurred in 31.8% of the 85 dogs treated with lapatinib and piroxicam, mainly alopecia and hyperpigmentation. They affected only 7.1% of the 42 dogs treated with piroxicam alone, giving the combination a relative risk of 4.4. Dogs with these events had longer progression-free survival, and the Cox model made them an independent prognostic factor (hazard ratio of 0.52) (Horita et al., 2026). These cutaneous events therefore serve as a marker of lapatinib efficacy.

Horita K, Yonezawa T, Momoi Y, Maeda S. Dermatological Adverse Events Associated With Lapatinib Treatment in Dogs With Urothelial Carcinoma: A Retrospective Study. Vet Dermatol. 2026 Oct;37(5):752-760. https://doi.org/10.1111/vde.70062

Feline papillomavirus is associated with previously undescribed lesions. Four cats were reported. Two had a benign proliferation of the sebaceous glands containing FcaPV5 DNA. A third had ulcerated lesions confined to the digits, one of which looked like a viral plaque and contained FcaPV2 DNA. The fourth had a viral plaque containing FcaPV8 DNA, whose cells carried large eosinophilic cytoplasmic bodies never described before, possibly specific to this viral type (Munday et al., 2026). Recognizing a viral origin matters, because an affected cat is more likely to develop further lesions.

Munday JS, Kelly-Bosma M, Lewis M, Lim V, Standage-Wardle J, Hardcastle M. Possible novel manifestations of papillomaviral skin disease in 4 cats, including sebaceous gland adenoma, viral plaques confined to the digits, and a viral plaque containing novel cytopathic features and felis catus type 8 DNA sequences. Vet Pathol. 2026 Oct 12:3009858261487716. Epub ahead of print. https://doi.org/10.1177/03009858261487716

Fluorescent light energy, a photobiomodulation therapy that promotes healing and reduces inflammation, was tested as an adjunct in cutaneous epitheliotropic lymphoma, an off-label use. Eight dogs received the treatment weekly for six weeks on one lesion, another lesion serving as a control treated with the vehicle alone, with three months of follow-up. No significant difference appeared between the two sites. Within-dog comparisons suggested a more favorable course of the treated lesions: 75% of treated nodular lesions remained stable. The severity of treated diffuse lesions decreased by up to 35.3%. More than 66% of owners rated the response as fair to excellent (Nowell et al., 2026). The treatment appears safe, without a statistically demonstrated effect.

Nowell S, Fantini O, Roman A, Milley C, Watson J, Bauer C. Fluorescent Light Energy (FLE) as an Adjunctive Therapy in Canine Cutaneous Epitheliotropic Lymphoma (CTCL). Vet Dermatol. 2026 Oct;37(5):788-796. https://doi.org/10.1111/vde.70098

7 Non-infectious, genetic and behavioral dermatoses

In sebaceous adenitis, neither breed nor type of treatment predicts response. One hundred twenty-two dogs followed over ten years in a multicenter dermatology group were reviewed, and 35 owners answered a survey. Response was excellent in 18.9% of dogs, good in 29.5%, fair in 21.3% and absent in 10.7%. In the remaining 18.9%, the disease progressed. Differences between breeds were not significant. Dogs on multimodal treatment reached the maintenance phase fastest, and 39% flared once maintenance was reached. Owners’ judgment did not agree with these objective categories (Batt et al., 2026). Treatment is therefore adjusted to each dog, according to its response.

Batt H, Griffin J, Daniels MW, Miller J. Therapeutic Outcomes and Owner Assessment in Canine Sebaceous Adenitis Across Breeds: A Multicentre Retrospective Analysis and Owner Survey. Vet Dermatol. 2026 Oct;37(5):650-658. https://doi.org/10.1111/vde.70095

The so-called doodle dysplasia of Poodles and their crosses receives a new name: dorsal melanotrichia. Twenty-nine dogs with a coat color change confined to the back were studied in the United States between 2019 and 2024. The mean age of onset was 4 years. Summer was the most frequently reported season of onset (46%), and recent grooming was noted in 57% of the dogs for which the information was available. The change most often formed a serpiginous pattern (67%), sometimes associated with alopecia or a change in hair texture. Among dogs that resolved, 71% relapsed 12 or 24 months later. Histology showed only mild changes, mainly outer root sheath apoptosis and altered follicular pigmentation, with no evidence of dysplasia (Kim et al., 2026a). A seasonal or environmental component is therefore possible.

Kim J, Linder K, Rosenkrantz W, Keating MK, Laporte C, Mount R, et al. Clinical, Histopathological and Epidemiological Features of Dorsal Melanotrichia of Poodles and Poodle Crosses. Vet Dermatol. 2026 Oct;37(5):761-774. https://doi.org/10.1111/vde.70066

A Finnish Lapphund with cutaneous sarcoidosis, diagnosed by histology, went into remission with oral oclacitinib. Cultures, special stains, electron microscopy and in situ hybridization had found no causative agent (Pänkälä et al., 2026). Idiopathic follicular mucinosis, a rare alopecia due to mucin deposition in the follicular wall, was successfully treated in a Golden Retriever, whose dermoscopic and histological features are described (Theuerkauff et al., 2026).

Pänkälä L, Schildt K, Huupponen A, Sukura A, Saari S. Canine Sarcoidosis Treated Successfully With Oclacitinib: A Case Report. Vet Dermatol. 2026 Oct;37(5):775-779. https://doi.org/10.1111/vde.70070

Theuerkauff E, Dettwiler M, Dölle M. Successful Treatment of Idiopathic Follicular Mucinosis in a Golden Retriever: Clinical, Dermoscopic and Histopathological Findings. Vet Dermatol. 2026 Oct;37(5):577-580. https://doi.org/10.1111/vde.70067

In three related mixed-breed puppies born with skin blistering and ulceration, junctional epidermolysis bullosa is associated with insertion of a SINE retrotransposon in the LAMA3 gene. Whole-genome sequencing of one affected puppy, compared with 1,538 control genomes, revealed a homozygous 240-base-pair insertion in exon 45, initially miscalled as a short heterozygous insertion. The variant fully co-segregated with the disease in the available family (Kiener et al., 2026). This initial error shows that sequencing data should be inspected visually so as not to miss this type of variant.

Kiener S, Kaufmann R, Brenner O, Jagannathan V, Leeb T. SINE Insertion in LAMA3 in Dogs With Junctional Epidermolysis Bullosa. Anim Genet. 2026 Oct;57(5):e70190. https://doi.org/10.1002/age.70190

Grooming varies widely from one cat to another, but psychogenic alopecia changes it in a recognizable way. One hundred eighteen videos of 29 healthy cats and seven shorthair cats with psychogenic alopecia were analyzed. Mean grooming bout duration differed neither with hair length nor with health status. Affected cats groomed fewer body regions than healthy shorthair cats, and they chewed their skin ten times longer. They also groomed the inner hind limbs longer, and the neck for a shorter time (Guillon et al., 2026). These results support classifying psychogenic alopecia as an abnormal repetitive behavior.

Guillon M, Naudin L, Cochet-Faivre N, Titeux E, Gilbert C. Exploring Normal to Abnormal Variations of Grooming Behaviours in Cats. Vet Dermatol. 2026 Oct;37(5):865-875. https://doi.org/10.1111/vde.70109

8 Diagnostic tools: dermoscopy and endocrinology

Dermoscopy is increasingly used in veterinary dermatology, but its data remain mostly descriptive. A systematic review included thirty studies in dogs, cats and horses, most of them case reports or case series. They covered alopecias, parasitic diseases, dermatophytosis, tumors, sebaceous lesions, inflammatory dermatoses and congenital vascular anomalies. Recurrent features closely resembled those of human dermatology, with differences related to the anatomy of each species (Plozner et al., 2026). A common terminology and prospective studies are still needed before broader use.

Plozner N, Errichetti E, Scarampella F. Diagnostic Value and Limitations of Dermoscopy in Humans and Animals: A Critical Comparative Analysis. Vet Dermatol. 2026 Oct;37(5):636-649. https://doi.org/10.1111/vde.70069

In canine calcinosis cutis, dermoscopy shows bright white structureless areas. Twelve lesions from twelve dogs with hypercortisolism, iatrogenic or spontaneous, were examined at ×10 magnification by three board-certified dermatologists and one resident. All showed these white areas and erythema. In eight lesions, the white areas surrounded plugs of yellowish to brown material emerging from follicular ostia or ulcerations. Vessels were mainly short, dilated, linear and curved (seven lesions out of twelve). Histology confirmed that the white areas corresponded to calcium deposits in the dermis (Scarampella et al., 2026).

Scarampella F, Denti D, Colombo S, Barbero P, Fabbri E, Brachelente C, et al. Dermoscopic Features of Calcinosis Cutis in 12 Dogs: An Observational Study. Vet Dermatol. 2026 Oct;37(5):630-635. https://doi.org/10.1111/vde.70064

In ACTH-dependent hyperadrenocorticism, plasma ACTH and the T4 to TSH ratio help identify dogs at low risk of pituitary enlargement. Twenty-three dogs were reviewed retrospectively: twelve with a normal-sized pituitary and eleven with an enlarged pituitary, defined by a pituitary height to brain area ratio of at least 0.31. ACTH was higher and the T4 to TSH ratio lower when the pituitary was enlarged, whereas IGF-1 did not distinguish the two groups. An ACTH cutoff of 44.3 pg/mL had a sensitivity of 72.7% and a specificity of 100%. A cutoff of 107.2 for the T4 to TSH ratio had a sensitivity of 100% and a specificity of 75%. A score combining these two cutoffs was calculated for each dog, and a score of zero had a negative predictive value of 100%. In a validation cohort of nine dogs with an enlarged pituitary, eight had a score of at least 1, but one dog had a score of zero (Chamagne et al., 2026). The tool therefore needs validation in larger cohorts.

Chamagne A, Desquilbet L, Pichard D, Rosenberg D, Benchekroun G. Predicting the presence of an enlarged pituitary gland in ACTH-dependent hyperadrenocorticism in dogs using T4, TSH and ACTH concentrations. Vet J. 2026 Oct 28;320:106952. Epub ahead of print. https://doi.org/10.1016/j.tvjl.2026.106952

Reverse triiodothyronine (rT3) distinguishes hypothyroidism well from nonthyroidal illness syndrome, which also lowers total T4. An assay by liquid chromatography coupled with mass spectrometry was validated in dogs, and the reference interval established in 47 healthy dogs ranges from 113 to 439 pg/mL. Median rT3 was 2.5 pg/mL in the 18 hypothyroid dogs, versus 229 pg/mL in the 23 dogs with nonthyroidal illness and 281 pg/mL in healthy dogs. To separate the two conditions, the area under the ROC curve reached 0.981 for rT3, versus 0.896 for free T4 measured by equilibrium dialysis (Ruß et al., 2026). rT3 therefore appears to be a useful parameter for this differential diagnosis.

Ruß J, Mueller RS, Glos K, Meindl C, Ritz S, Müller DC, et al. Serum reverse triiodothyronine in dogs with hypothyroidism, nonthyroidal illness syndrome and healthy dogs. PLoS One. 2026 Oct 5;21(10):e0357106. https://doi.org/10.1371/journal.pone.0357106

References