Cutaneous vasculitis in small animals

Diascopy and histopathological evaluation of nonblanching erythematous dermatoses in dogs

BACKGROUND

Diascopy is a point-of-care diagnostic test used to differentiate skin erythema due to vascular dilation from haemorrhage. In the veterinary literature, only a handful of diseases have been described to be associated with a negative (nonblanching) diascopy result, and histological investigation of haemorrhage has been inconsistent.

OBJECTIVES

Retrospective study to undertake a histopathological investigation of canine, nonblanching erythematous dermatoses for the presence or absence of haemorrhage and vascular changes.

MATERIALS AND METHODS

Skin biopsies from dogs presented with moderate-to-severe nonblanching erythema were evaluated histologically. Additionally, clinical data about each patient were analysed.

RESULTS

Twenty cases were identified with nonblanching erythema. Diagnoses included vasculopathy (n = 6), canine eosinophilic dermatitis (n = 3), cutaneous epitheliotropic T-cell lymphoma (n = 2), and one case each of sterile granuloma and pyogranuloma syndrome, German shepherd dog pyoderma, multiple mast cell tumours, haemangiosarcoma, exfoliative cutaneous lupus erythematosus, canine leishmaniosis with sebaceous adenitis, sebaceous adenitis with concurrent dermatophytosis, calcinosis cutis and canine atopic dermatitis with insect-bite reaction. One or more vascular changes were present in all 20 cases and included perivascular oedema, endothelial swelling and neutrophilic infiltration of vessel walls. Haemorrhage was identified in 17 of 20 cases (85%). Three cases without dermal haemorrhage were calcinosis cutis, sebaceous adenitis with dermatophytosis and canine atopic dermatitis with insect-bite reaction.

CONCLUSIONS AND CLINICAL RELEVANCE

Negative diascopy was associated with haemorrhage and vascular pathological findings in the majority of cases, yet not all. Haemorrhage was identified histologically in all diseases previously reported as nonblanching as well as in a few additional diseases.

Clinical and histopathological features of rostrolateral nasal alar arteriopathy of German shepherd dogs

BACKGROUND

Dermal arteritis of the nasal philtrum (DANP) has been described in large-breed dogs.

OBJECTIVES

To characterise clinically distinct, discrete fissures of the dorsolateral nasal alae associated with severe bleeding in German shepherd dogs (GSDs).

ANIMALS

Fourteen privately owned GSDs with linear rostrolateral nasal alar fissures and a histopathological diagnosis of nasal vasculopathy.

MATERIALS AND METHODS

Retrospective analysis of medical records and histological slides.

RESULTS

Mean age of onset was 6 years. Before biopsy, episodic arteriolar bleeding was noted in 11 of the 14 (79%) dogs. Slide analysis revealed enlarged nasal arterioles with expanded vascular tunics and luminal stenosis beneath ulcers. Histopathological lesions consistent with mucocutaneous pyoderma and/or facial discoid lupus erythematosus were present in 5 of the 14 (36%) dogs. Enlarged arterioles stained blue with Alcian blue and Masson's trichrome stains, consistent with deposition of mucin and collagen, respectively. Immunohistochemical stains (neutrophil myeloperoxidase, IBA1, CD3) were performed. CD3 was negative for all dogs, whilst neutrophil myeloperoxidase and IBA1 occasionally demonstrated intramural neutrophils (3 of the 14 dogs, 21%) or histiocytes (1 of the 14 dogs, 7%) in altered vessels, respectively. All dogs underwent medical management and/or surgical excision. Treatments included tacrolimus, prednisone, ciclosporin-modified, pentoxifylline, antimicrobials and doxycycline/niacinamide. No dogs were treated with antimicrobials alone. For seven dogs with long-term follow-up, treatment response was complete in five (71%) and partial in two (29%), with six of the seven (86%) receiving immunomodulatory treatments to maintain remission.

CONCLUSION AND CLINICAL RELEVANCE

Nasal alar arteriopathy of GSDs shares histopathological changes with DANP. It has characteristic clinical and histopathological features and appears amenable to immunomodulation.

Retrospective evaluation of the etiology and clinical characteristics of peripheral edema in dogs

BACKGROUND

The prevalence and clinical characteristics of different etiologies of peripheral edema in dogs are unknown.

HYPOTHESIS/OBJECTIVES

To determine the prevalence of different etiologies of peripheral edema, describe clinical characteristics that vary among etiologies, and report survival times.

ANIMALS

Five hundred twenty-seven dogs with peripheral edema.

METHODS

Retrospective medical record review. Differences in clinical variables among etiology groups were assessed by Kruskal-Wallis testing with post hoc pairwise Dunn's testing and Chi-square testing with Monte Carlo simulation.

RESULTS

The most common etiologies of peripheral edema in dogs were vasculitis (n = 193, 37%), lymphatic/venous obstruction (LVO; 114, 22%), and hypoalbuminemia (94, 18%). Right-sided congestive heart failure (R-CHF) was uncommon (25, 5%). Edema was localized in 377 (72%) dogs and generalized in 142 (27%) dogs, and hypoalbuminemia was more likely to cause generalized edema compared to LVO or vasculitis (P < .0001). Concurrent abdominal effusion (155, 29%) was more common than pleural (77, 15%) or pericardial (12, 2%) effusion. Abdominal and pleural effusion occurred more commonly in dogs with hypoalbuminemia or R-CHF compared to LVO or vasculitis (P < .0001).

CONCLUSIONS AND CLINICAL IMPORTANCE

Distribution of edema, concurrent cavitary effusions, and clinicopathological data can help predict the underlying etiology of peripheral edema in dogs.

Dermatological Problems of Brachycephalic Dogs

Brachycephalic dogs are not only affected by brachycephalic obstructive airway syndrome (BOAS), but are also frequently referred to veterinary dermatologists for skin conditions, with English bulldogs and pugs particularly over-represented. Some skin diseases, such as skin fold dermatitis, are directly associated with the abnormal anatomic conformation of brachycephalic dogs, while for others, such as atopic dermatitis and viral pigmented plaques, there is an underlying genetic basis or a general predisposition. Anatomic alterations associated with brachycephaly, leading to fold formation of the skin and stenosis of the ear canal, together with primary immunodeficiencies described in some breeds, favor the development of pyoderma, Malassezia dermatitis, and otitis externa/media. In addition, the frequently neglected but often lifelong dermatological problems of brachycephalic dogs are an important consideration when discussing genetic and medical conditions affecting the welfare of those dogs. Here we review the current state of knowledge concerning dermatological problems in brachycephalic dogs and combine it with clinical experience in the management of these challenging disorders.

Vasculitis cutánea asociada a Ehrlichiosis canina. Reporte de un caso clínico

La Ehrlichiosis canina puede desencadenar vasculitis cutánea por mecanismos inmunopatogénicos, como lo hacen las Rickettsia y Leishmania, entre otros. La vasculitis se refiere a la inflamación de los vasos sanguíneos de la piel que resulta en alteración del flujo sanguíneo y necrosis isquémica de la piel. Este trabajo tuvo como objetivo reportar el caso de un perro, macho entero de cuatro años de edad, que presentaba lesiones alopécicas erosivas-ulcerativas y algunas costrosas en cabeza, plano nasal, regiones de flexión, pabellón auricular y punta de cola. Se realizó un hemograma, confirmando anemia, normocítica normocrómica no regenerativa, leucocitos aún normales con linfopenia, y trombocitopenia. En el frotis sanguíneo se determinó la presencia de mórulas basofílicas en monocitos, hallazgos compatibles con Ehrlichia spp. Se procedió a tratar al paciente con Prednisolona 1 miligramo·kilogramo-1 –mg·kg-1– cada 24 horas –h– por 10 días –d-, Pentoxifilina 15 mg cada 12 h por 120 d, 500 mg de Doxiciclina y 500 mg de Niacinamida cada 12 h por 20 d. Se realizaron dos controles (lesiones cutáneas) una a los 21 d y la otra a los 60 d. Se concluye que el tratamiento fue satisfactorio, donde el paciente se recuperó totalmente luego del tratamiento administrado.

Case report: Lympho-histiocytic meningoencephalitis with central nervous system vasculitis of unknown origin in three dogs

Meningoencephalitis of unknown origin (MUO) is an umbrella term for a variety of subtypes of meningoencephalitis of dogs and cats with no identifiable infectious agent. In dogs, granulomatous meningoencephalitis (GME), necrotizing meningoencephalitis (NME), and necrotizing leukoencephalitis (NLE) are the most commonly reported subtypes. However, sporadically there are reports about other subtypes such as greyhound encephalitis or eosinophilic meningoencephalitis. The following case series presents three dogs with peracute to acute progressive signs of encephalopathy. The magnetic resonance imaging (MRI) of two dogs (post mortem n = 1/2) showed severe, diffuse swelling of the cortical gray matter with increased signal intensity in T2weighted (w) and fluid-attenuated inversion recovery (FLAIR) and decreased signal intensity in T1w. Additionally, focal to multifocal areas with signal void in both dogs and caudal transforaminal herniation of the cerebellum in one dog was observed. Post mortem histopathological examination revealed lympho-histiocytic encephalitis and central nervous system (CNS) vasculitis in all dogs. No infectious agents were detectable by histopathology (hematoxylin and eosin stain), periodic acid-Schiff reaction (PAS), Ziehl-Neelsen stain and immunohistochemistry for Canine adenovirus-1, Parvovirus, Listeria monocytogenes, Parainfluenzavirus, Toxoplasma gondii, Herpes-suis virus, Pan-Morbillivirus, Tick born encephalitis virus, Severe acute respiratory syndrome coronavirus (SARS-CoV) 2. Furthermore, two dogs were tested negative for rabies virus. To the best of the authors' knowledge, this is the first report of a lympho-histiocytic encephalitis with CNS vasculitis with no identifiable infectious agent. It is suggested to consider this as an additional subtype of MUO with severe clinical signs.

[Life-threatening acute neutrophilic vasculitis in a Shar-Pei puppy]

A 3-month old male Shar-Pei was presented for lethargy, fever and cutaneous edema. Further investigations revealed superficial pyoderma with Streptococcus canis and an acute neutrophilic vasculitis. Symptomatic and antibiotic treatment in combination with immunosuppressive treatment (initially prednisolone, later cyclosporine) treatment was performed. In the course of the disease complications such as dyspnea, anemia, skin ulceration, skin necrosis and secondary bacterial skin infection with multiresistant bacteria occurred. After intensive care treatment the dog was discharged from the hospital 38 days later. Within the following weeks the dosage of the immunosuppressants were reduced and the drugs were discontinued after 4 months.

Excitement-Induced Cutaneous Bleeding (Haematidrosis-like) in a Dog

A 15-month-old intact female Pitbull was referred because of recurrent, episodic, self-limiting, excitement-induced bleeding from nontraumatised skin. No abnormalities were detected upon physical examination. Subsequently, the dog went for a walk under the direct supervision of one of the authors, became overexcited and, after approximately five minutes, bloody liquid, with a patchy distribution, appeared along the hair shafts of the face and neck. The affected skin was congested, partially blanching on diascopy and bloody liquid was oozing from the follicular openings. Urticaria, dermographism and hypertension were excluded, the complete blood count and coagulation profile were within the reference ranges and an analysis of the bloody exudate confirmed its blood components. The cutaneous bleeding of the dog followed a self-limited course, with no episodes during the last two years. Clinical and laboratory findings and the long-term evolution of this dog bear striking similarities to haematidrosis, a rare human disease of multifactorial aetiology and equivocal pathogenesis.

Cutaneous Vasculopathy and Pulmonary Thromboembolism in an Unstable Diabetic Cat

A 6-year-old, male-neutered, domestic short-haired cat was referred for further management of a 3-month history of uncontrolled diabetes mellitus. The cat visited the hospital on 3 occasions during a 3-week time period. Hyperglycemia was documented at all visits. The cat initially presented with evidence of hypovolemia, cranial abdominal pain, and dehydration. Moderate hyperglycemia, mild ketonemia, and severe hypokalemia were documented. A 3 × 2 cm skin lesion with associated alopecia and erythema was first noticed at a routine follow-up examination (visit 2) 1 week later. A diagnosis of diabetic ketoacidosis was made 6 days later. The previously identified skin lesion now measured 6 × 2.5 cm. Two episodes of respiratory distress were identified at this visit, with no evidence of cardiac or pulmonary pathology. The cat developed a moderate anemia (packed cell volume 16 %, total solids 7.9 g/dL) on the fifth day of hospitalization. Fluid therapy, electrolyte supplementation, regular insulin, anti-emetic, and analgesia medications were administered during visits 1 and 3. Due to development of anemia, suspected pulmonary thromboembolism events and progression of skin lesions, euthanasia was elected. A diagnosis of cutaneous vasculopathy with secondary ischemic necrosis was made postmortem and pulmonary thromboembolism was confirmed. To the authors' knowledge, this is the first report of cutaneous vasculopathy and pulmonary thromboembolism in a cat with confirmed diabetes mellitus, warranting further research to assess if hypercoagulability is common in this patient population, as routine thromboprophylaxis and anticoagulation may be potentially indicated.

New findings associated with presumptive systemic lupus erythematosus in a kitten

CASE SUMMARY

An 8-month-old neutered male domestic shorthair kitten was examined for anorexia, lethargy and palatine ulcers. Systemic lupus erythematosus (SLE) was suspected based on a positive antinuclear antibody (ANA) titer and six manifestations of autoimmunity: fever, paronychia, oral ulcers, proteinuria, thrombocytopenia and leukopenia. Mastocytemia was observed on the blood smear. Although the clinical presentation of this case meets the classification criteria for SLE in humans, tick-borne disease and histopathology evaluation of the oral and cutaneous lesions would have been necessary to support a definite diagnosis of SLE. Baseline ANA titration was performed in two laboratories with conflicting results, which may reflect substrate differences used for the titration, but a false-positive result cannot be excluded. The cat received prednisolone and all clinical and laboratory abnormalities resolved after two months of treatment. Subsequent ANA titers remained positive and were not correlated to the patient's clinical progression.

RELEVANCE AND NOVEL INFORMATION

This report describes new findings associated with a presumptive diagnosis of SLE in a kitten, highlighting that SLE may not be ruled out even in young cats and may be associated with mastocytemia. ANA titration is part of the initial diagnostic work-up of SLE but is a non-specific test and discrepancies can be observed between laboratories. The titration of more specific antibodies such as those used in humans would be helpful to diagnose SLE. ANA titration may not correlate with clinical activity of SLE; hence, the interest of an ANA titer follow-up to establish disease control warrants further investigation.

Subconjunctival haemorrhage in 147 dogs

OBJECTIVES

To identify differential diagnoses for subconjunctival haemorrhage in dogs.

MATERIALS AND METHODS

Retrospective case series.

RESULTS

Of 147 dogs with subconjunctival haemorrhage, 119 had a history of trauma. The most common types of injury were vehicular trauma (47/119) and dog attacks (32/119). Confirmed or suspected non-accidental injury was reported for 5/119. Of the 28 dogs without a history of trauma, 13 had a bleeding disorder and of these, immune-mediated thrombocytopenia was the most common diagnosis (9/13). Other causes included seizure disorders (4/28), vasculitis (3/28) and ocular or periocular disease (3/28).

CLINICAL SIGNIFICANCE

Subconjunctival haemorrhage in dogs can be secondary to a wide range of injuries and systemic diseases, bleeding diathesis or ocular disease.

Hyperhomocysteinemia in Greyhounds and its Association with Hypofolatemia and Other Clinicopathologic Variables

Background

Folate and cobalamin are essential cofactors for homocysteine (HCY) metabolism. Hyperhomocysteinemia, a multifactorial condition, may reflect B vitamin deficiency and is associated with increased risk of cardiovascular disease, thrombosis, and neurodegenerative and chronic gastrointestinal diseases in humans. Hyperhomocysteinemia has been reported in Greyhounds with suspected chronic enteropathy.

Objectives

To evaluate the frequencies of and the association between hypofolatemia and hyperhomocysteinemia in Greyhounds.

Animals

Data and serum samples from 559 Greyhounds.

Methods

Nested case‐control study. The frequency of hypofolatemia in Greyhounds was determined by a laboratory database search. The relationship between hyperhomocysteinemia (measured by gas chromatography‐mass spectrometry) and hypocobalaminemia and hypofolatemia was evaluated, and its frequency compared between healthy Greyhounds and Greyhounds with thrombosis or chronic diarrhea.

Results

Hypofolatemia was identified in 172 of 423 (41%) Greyhounds and was more common in hypo‐ than in normocobalaminemic dogs (49% vs. 35%; P = .0064). Hyperhomocysteinemia was detected in 53 of 78 (68%) of Greyhounds, being more common in hypo‐ than in normofolatemic dogs (88% vs. 59%; P = .0175). All healthy Greyhounds, 21 of 30 (70%) of dogs with chronic diarrhea and 6 of 8 (75%) of those with thrombosis, were hyperhomocysteinemic. Serum HCY concentrations were inversely correlated with serum folate concentration (ρ = −0.28; P = .0386) and were positively associated with serum albumin concentration (ρ = 0.66; P = .0022).

Conclusions and Clinical Relevance

Hyperhomocysteinemia occurs frequently in the Greyhound population. Its association with hypofolatemia suggests decreased intracellular availability of B vitamins, but the functional implications warrant further investigation. Hyperhomocysteinemia in Greyhounds potentially may serve as a spontaneous canine model to further investigate hyperhomocysteinemia in humans.

Atherosclerosis associated with vasculopathic lesions in a golden retriever with hypercholesterolemia

A 2-year-old neutered male golden retriever dog presented for lameness secondary to ulcerations of multiple digital paw pads was diagnosed with vasculitis and hypercholesterolemia. Despite treatment, ischemic necrosis progressed to include all distal extremities and the dog eventually expired due to myocardial infarction secondary to severe atherosclerosis. The rapid demise and the dermatologic lesions may have been secondary to cholesterol embolism syndrome which has never before been reported in a dog.