Dermatology

Take-away points:

• Biofilm (the protective matrix that bacteria and yeast build on the ear canal surface) is a key driver of chronic and treatment-resistant otitis externa. Once established, biofilms dramatically reduce the effectiveness of topical antimicrobials.
• This study compared the in vitro antibiofilm activity of three otic cleansers: PHMB-EDTA (e.g. Otoflush), N-acetylcysteine (NAC), and Triz-EDTA, against the six most common canine otitis pathogens, including Staphylococcus pseudintermedius, Pseudomonas aeruginosa, and Malassezia pachydermatis.
• Otoflush was the standout performer, demonstrating potent antibiofilm activity at low concentrations against all six pathogens. NAC showed activity against bacterial pathogens only, though at very high concentrations and with poor efficacy against Malassezia. Triz-EDTA showed minimal antibiofilm activity against most pathogens, even at the highest concentration tested.
• Incorporating Otoflush as a pre-treatment ear cleaner – particularly in chronic or recurrent cases – is supported by the strongest available in vitro evidence for biofilm disruption across the full spectrum of common otitis pathogens. As with all in vitro studies, clinical trials are needed to confirm whether these findings translate to improved patient outcomes.
• We often underestimate how much perpetuating factors drive recurrent otitis – a collaborative approach with your local dermatologist gets to the root cause and delivers better long-term outcomes for your patients.

Take-away points:

• Erythemato-ceruminous otitis externa (ECOE) – characterised by erythema and waxy discharge – is one of the most common ear presentations in dogs and is frequently driven by Malassezia overgrowth and disruption of the normal ear microbiome.
• This prospective clinical study assessed whether a ceruminolytic ear cleaner alone could improve clinical signs and restore microbial balance in 30 dogs with mild-to-moderate Malassezia-associated ECOE.
• By Day 14, pruritus scores had reduced by 77%, clinical scores by 66%, and cytological scores by 76% – all statistically significant. Crucially, Malassezia culture converted from positive to negative in all ears by Day 14, and fungal diversity in the ear microbiome significantly increased, suggesting a genuine restoration of microbial balance rather than just surface-level improvement. Bacterial composition was unaffected.
• This study provides some evidence that a ceruminolytic ear cleaner (e.g. Sonotix or Epiotic SIS) used as a sole treatment may resolve mild-to-moderate Malassezia ECOE within two weeks, reinforcing that ear cleaning is not merely supportive but can be therapeutic in its own right for appropriate cases. Due consideration should be given to each component of a topical regimen for managing otitis externa; there really isn’t a template approach.

Medicine

• Frunevetmab is a felinised anti–nerve growth factor monoclonal antibody widely used for the management of osteoarthritis pain in cats, with documented efficacy and increasing clinical utilisation.
• Analysis of real-world pharmacovigilance data from the FDA Animal Drug Adverse Events database (2022–2024) identified over 5,000 reports associated with its use. The most frequently reported adverse effects were dermatological, including pruritus, alopecia, dermatitis, and cutaneous lesions, with the strongest safety signals noted for skin ulceration and injection site pain.
• In addition to dermatological findings, neurological adverse effects have been reported, including paresis and other abnormalities suggestive of altered neuromuscular or central nervous system function.
• There is also emerging concern regarding potential renal implications. Baseline and ongoing monitoring of renal parameters and overall clinical status is therefore recommended when using this therapy in this population.

• Hypersomatotropism (HST) in cats is a chronic endocrine disorder driven by excess growth hormone (GH), most commonly due to a functional pituitary adenoma or hyperplasia. This results in increased insulin-like growth factor-1 (IGF-1) and a range of multisystemic effects. Although it is classically linked with diabetes mellitus (DM), this study highlights that HST can occur in non-diabetic cats and may therefore be under-recognised.
• In this retrospective cohort of 28 cats, the population was largely older, male, and overweight, with markedly increased IGF-1 concentrations but variable clinical expression.
• Clinical signs in non-diabetic cats were often subtle and inconsistent, with 68% showing features compatible with acromegaly. These included prognathia inferior, weight gain, broad facial features, abdominal distension, respiratory stridor, and polyphagia.
• Neurological signs were less common but did occur, likely reflecting the mass effect of a pituitary lesion.
• Clinicopathological changes were generally mild and non-specific, including hyperproteinaemia, mild azotaemia, and reduced urine specific gravity. A hypertrophic cardiomyopathy phenotype was identified in a subset of cats, and chronic kidney disease (CKD) was a frequent comorbidity, emphasising the systemic consequences of prolonged GH and IGF-1 excess.

Oncology

• Many bladder tumours are considered unresectable due to their trigonal location – but not all. If they have a more apical location, then a partial cystectomy, even if not curative, can improve the outcome.
• In this retrospective study of 30 dogs and cats with nontrigonal UC treated with partial cystectomy, median survival was 512 days, and complete surgical margins plus adjuvant chemotherapy were associated with better outcomes.
• So, surgically excise or debulk where possible, then follow up with some form of medical therapy to help your patients.

The JAAHA 2026 guidelines for primary care clinicians for the diagnosis, staging, client communication, supportive care, and appropriate specialist referral is now available. It reminds us that many cancer patients can be managed or co-managed effectively in first opinion practice.

ECC

Oclacitinib (Apoquel) intoxication

In 2023 Apoquel became available in a chewable form. This has resulted in a significant rise in large overdoses in both dogs and cats. The increase in palatability appears to be the driving cause (beef flavoured). We are seeing toxicoses resulting in severe morbidity and at times mortality, compared to the original tablet formulation of “mild GI only signs”.

Potential clinical signs / body system affected

• GI: vomiting, diarrhoea, abdominal pain
• Cardiovascular: hypotension, tachycardia, arrhythmias, new murmurs
• CNS: lethargy, dull mentation, elevated third eyelid
• Renal: acute kidney injury (AKI)
• Hepatic: hepatotoxicity ± coagulopathy
• Other: facial/periocular swelling
• Outcome: deaths/euthanasia reported in some cases

Dose-related effects

• ~10–15 mg/kg: GI, cardiovascular, CNS signs
• ~12–38 mg/kg: AKI (dogs and cats)
• Cats may be more sensitive
• AKI can develop within 12–72 hours (marked ↑ BUN/creatinine)

It is now recommended to be more aggressive with initial management for ingestions ≥10 mg/kg.

Surgery

• Perineal wounds can be challenging to manage
• Several flaps have been described to close wounds in this area:
  • Caudal superficial epigastric axial pattern flap
  • Lateral caudal axial pattern flap (requires tail amputation)
  • Deep circumflex iliac axial pattern flap
  • Flank fold flap
• Distance to perineal region increases risk of distal necrosis of these flaps if performed without preconditioning
• Angiosome mapping for the dorsal and ventral perineal arteries showed the primary cutaneous branch of the ventral and dorsal perineal arteries were consistently present in male and female dogs.
• The ventral perineal artery cutaneous angiosome was subjectively more robust than the dorsal perineal angiosome.
• The primary cutaneous angiosomes of both arteries extended at least two-thirds of the length of the caudal thigh.
• A single clinical case reported for a perineal wound repaired successfully with a dorsal perineal artery flap.
• Conclusion: The dorsal and ventral perineal arteries provide a rich blood supply to the skin of the caudal thigh. Axial pattern skin flaps created within these angiosomes may survive consistently but further clinical cases are required to confirm this in practice. This flap can be considered for closing small wounds in the perineal, ventral tail region.

• A previous study described a U-shaped scrotal subdermal plexus flap with its base located at its rostral border, used to reconstruct perineal skin defects ventral to the anus, but it had a high incidence of necrosis to the caudal border of the flap.
• In this anatomic perfusion study, the dorsal scrotal arteries appear to supply a larger area than the ventral scrotal arteries and so are likely to allow creation of more robust flaps.
• Angiograms suggest flap borders should be about 2.5–3 cm lateral to the midline in a large-breed dog, or at least the same width as the scrotal pouch, to follow the rule of thumb for creation of axial flaps.
• These incisions can be extended to just dorsal to the ischiatic table without concern for transection of the important vasculature.
• The distal border of the flap is the cranial edge of the scrotum. Care should be taken during skin flap elevation to preserve both ventral perineal arteries as they course toward the scrotum.
• A modified scrotal flap could be considered as an option for moderate sized skin defects within its reach, with acceptable cosmetic result and minimal functional impact.
• No case reports are published to support the use of this flap, however it can be considered for small wounds in this area.
• For large wounds in the perineal area, consider axial skin flaps.