Canine and Feline Eosinophilic Skin Diseases

Feline eosinophilic sclerosing fibroplasia – a characteristic inflammatory response in sites beyond the gastrointestinal tract: case report and proposed nomenclature

Case summary

An adult male neutered Russian Blue cat presented for a right-sided nasal mass with bilateral retropharyngeal and right mandibular lymphadenomegaly. Medial retropharyngeal lymph node excision with nasal mass biopsy revealed eosinophilic sclerosing lymphadenitis and eosinophilic and lymphoplasmacytic rhinitis, respectively. Bacterial culture of the lymph node grew Pseudomonas aeruginosa, and treatment with pradofloxacin was started. Despite initial improvement, clinical signs recurred after 9 months, and fine-needle aspirates of the right mandibular and left medial retropharyngeal lymph nodes showed eosinophilic and mastocytic infiltration. Bacterial culture of the left medial retropharyngeal lymph node grew P aeruginosa, and treatment with anti-inflammatory doses of prednisolone and, later, marbofloxacin was instituted.

Relevance and novel information

This report describes a case of feline eosinophilic sclerosing lymphadenitis diagnosed outside of the abdominal cavity and is the first case reported to be associated with P aeruginosa. Feline eosinophilic sclerosing lymphadenitis should be considered as a differential for lymphadenopathy occurring in areas other than the abdominal cavity. Feline eosinophilic sclerosing lymphadenitis may develop in cats due to a species-specific inflammatory response to chronic bacterial and fungal infections.

Management of Severe Oral Inflammatory Conditions in Dogs and Cats

Severe oral inflammatory disease is not uncommon in the mouths of canine and feline patients. An approach to oral diagnosis is offered. This article discusses a brief review of important points in the oral diagnosis and management of main canine (canine chronic ulcerative stomatitis (CCUS), eosinophilic stomatitis, and Wegener's granulomatosis (WG)) and feline diseases (feline gingivostomatitis/caudal stomatitis, oral eosinophilic lesions, pyogenic granuloma, and autoimmune diseases with oral manifestations), and-whereby possible-information about the current understanding of disease pathogenesis and treatment is offered.

Model Based Evaluation of Hypersensitivity Adverse Drug Reactions to Antimicrobial Agents in Children

Drug use in children is-in most cases-supported by extrapolation of data generated from clinical trials in adult populations. This puts children at higher risk of developing adverse drug reactions (ADRs) due to "off-label" use of drugs and dosing issues. Major types of ADRs are drug hypersensitivity reactions, an idiosyncratic type of ADRs that are largely unpredictable and can cause high morbidity and mortality in a hard-to-identify specific population of patients. Lack of a complete understanding of the pathophysiology of DHRs and their unpredictive nature make them problematic in clinical practice and in drug development. In addition, ethical and legal obstacles hinder conducting large clinical trials in children, which in turn make children a "therapeutic orphan" where clear clinical guidelines are lacking, and practice is based largely on the personal experience of the clinician, hence making modeling desirable. This brief review summarizes the current knowledge of model-based evaluation of diagnosis and management of drug hypersensitivity reactions (DHRs) to antimicrobial drugs in the pediatric population. Ethical and legal aspects of drug research in children and the effect of different stages of child development and other factors on the risk of DHRs are discussed. The role of animal models, in vitro models and oral provocation test in management of DHRs are examined in the context of the current understanding of the pathophysiology of DHRs. Finally, recent changes in drug development legislations have been put forward to encourage drug developers to conduct trials in children clearly indicate the urgent need for evidence to support drug safety in children and for modeling to guide these clinical trials.

A case of an intramural, cavitated feline gastrointestinal eosinophilic sclerosing fibroplasia of the cranial abdomen in a domestic longhair cat

Case summary

A 5-year-old neutered male domestic longhair cat was presented for the investigation of a cranial abdominal mass following a 1-month history of inappetence and lethargy. Abdominal ultrasound revealed a large cavitated mass confluent with the mesenteric aspect of the descending duodenum. At surgery, the mass was found to involve the pylorus, proximal duodenum and pancreas, and was non-resectable. Histopathological examination of surgical biopsies revealed a non-neoplastic process involving eosinophils and fibroplasia.

Relevance and novel information

This case report describes an uncommon feline gastrointestinal pathology with an unusual appearance that may provide an additional differential diagnosis other than neoplasia or abdominal abscess when confronted with a cavitated abdominal mass in cats.

Feline oral cavity lesions diagnosed by histopathology: a 6-year retrospective study in Portugal

OBJECTIVES

The aim of this study was to analyse the frequency of oral cavity lesions in cats, their anatomical location and histological diagnosis, and the effect of life stage, breed and sex on different diagnoses.

METHODS

For this purpose, a retrospective study comprising 297 feline oral cavity lesions was performed over a 6-year period between 2010 and 2015. Histopathological records from the DNAtech Pathology Laboratory (Lisbon, Portugal) were analysed.

RESULTS

The incidence of oral disease was higher in male cats (n = 173; 58.4%), mature adults (ranging from 7 to 10 years old [n = 88; 33.0%]) and in the European Shorthair breed (n = 206; 73.6%). The gingiva was the site where oral lesions were most commonly found, with 128 samples (43.1%). Incisional biopsies were used to obtain the majority of samples (n = 256; 86.2%), while excisional biopsies and punch biopsies were performed in 36 (12.1%) and five (1.7%) cases, respectively. Inflammatory and neoplastic lesions accounted for 187 (63%) and 110 (37%) of the studied cases, respectively. Malignancies were found in >80% of neoplastic cases. Feline chronic gingivostomatitis was the most common histological diagnosis (n = 116; 39.1%), followed by squamous cell carcinoma (n = 49; 16.5%) and eosinophilic granuloma complex (n = 33; 11.1%).

CONCLUSIONS AND RELEVANCE

The present work, involving a large series of samples of feline oral cavity lesions, from numerous geographically scattered practices and all examined at a reference veterinary pathology laboratory, adds important new understanding of the epidemiology of feline oral disease.

Bilateral Sterile Pyogranulomatous Keratitis in a Dog

Purpose

To describe the clinicopathologic features of bilateral sterile pyogranulomatous keratitis in a 16-year-old spayed female rat terrier dog.

Methods

The dog presented one year prior due to ulceration of the right and left corneas. The ulcers healed but plaques developed on both eyes which progressed, during the course of one year, to cover both the left and the right corneas. Due to the animal's loss of sight and its painful condition, bilateral enucleation was performed with submission of the eyes for histopathology.

Results

Microscopic examination revealed bilateral pyogranulomatous keratitis absent of etiological organisms.

Conclusions

To the authors' knowledge, this is the first documented case of bilateral sterile pyogranulomatous keratitis in a dog.

Clinicopathological Features, Risk Factors and Predispositions, and Response to Treatment of Eosinophilic Oral Disease in 24 Dogs (2000-2016)

The objectives of this study were to retrospectively describe clinicopathological features of eosinophilic oral disease in dogs, to identify possible risk factors or predispositions to the condition, and to report overall treatment response. Canine medical records from a veterinary teaching hospital and private referral practice over a 17-year period were reviewed for a diagnosis of eosinophilic oral disease. Twenty-four dogs with 26 lesions met the inclusion criteria. Patient mean age and body weight were 6.8 (3.8) years and 13.4 kg, respectively. Fifteen breeds were represented including Cavalier King Charles spaniel (16.7%), Labrador retriever (12.5%), and West Highland white terrier (12.5%). Eosinophilic lesions were found in the palate (65.4%), tongue (26.9%), and other oral locations (7.7%). Median follow-up time was 5 months. Analysis revealed statistically significant associations between lesion location and body weight (palatal and tongue lesions were more likely in smaller dogs, whereas lesions in the other category [lip or mucosa] were more likely in larger dogs). There was a correlation in lesion location and resolution (all dogs with palatal lesions became asymptomatic at their last recheck), and resolution and the use of antibiotics plus prednisone (greater likelihood of resolution without the use of this combination). Seventy percent of asymptomatic dogs resolved without medication or with allergen therapy alone, suggesting that asymptomatic dogs may respond well to conservative management. No associations were found between lesion location and breed, signalment and response to therapy, lesion resolution and the use of glucocorticoids, or significance of peripheral eosinophilia.

EAACI position paper: Comparing insect hypersensitivity induced by bite, sting, inhalation or ingestion in human beings and animals

Adverse reactions to insects occur in both human and veterinary patients. Systematic comparison may lead to improved recommendations for prevention and treatment in all species. In this position paper, we summarize the current knowledge on insect allergy induced via stings, bites, inhalation or ingestion, and compare reactions in companion animals to those in people. With few exceptions, the situation in human insect allergy is better documented than in animals. We focus on a review of recent literature and give overviews of the epidemiology and clinical signs. We discuss allergen sources and allergenic molecules to the extent described, and aspects of diagnosis, prophylaxis, management and therapy.

Ciclosporin and the cat: Current understanding and review of clinical use

Practical relevance: Ciclosporin (CsA) is a systemic immuno-modulatory drug widely used to treat immune-mediated diseases in humans and veterinary species. CsA was registered for use in cats in the USA and Europe in 2011, and is indicated for the treatment of chronic allergic dermatitis at a recommended daily dose of 7 mg/kg PO.

AUDIENCE

This review will be of interest to all veterinarians working with cats, given the wide range of potential applications of CsA and its safety profile. Although the drug is currently only licensed to treat chronic allergic dermatitis in cats, a small number of reports describe its use in non-dermatological conditions. Evidence base: This article reviews the mechanism of action, pharmacokinetics, drug interactions, adverse effects and clinical use of CsA, both for the licensed indication and for off-label use in the feline patient. Information presented has been summarised from the existing literature on CsA, with specific interest in studies carried out in cats. For its licensed indication, chronic allergic dermatitis, evidence provided includes randomised, placebo or prednisolone-controlled studies (EBM grade I) and prospective or retrospective open trials.

A case of feline gastrointestinal eosinophilic sclerosing fibroplasia associated with phycomycetes

Feline gastrointestinal eosinophilic sclerosing fibroplasia (FGESF) is a recently described inflammatory condition of domestic cats with unknown aetiology. A proportion of cases of FGESF are associated with bacteria, but antibiotic treatment is ineffective. It has been hypothesized that genetically predisposed cats may develop FGESF in response to the introduction of bacteria or other antigens into the intestinal wall. A 9- month-old male Persian cat presented with a history of marked acute haematemesis. A mass (10 cm diameter) was detected within the pylorus and proximal duodenum and this was not surgically accessible. On necropsy examination the duodenal wall was seen to be markedly thickened with extensive mucosal ulceration. Microscopically, there were haphazardly oriented trabecular bands of dense eosinophilic collagen, separated by wide, clear areas containing variable numbers of fibroblasts, eosinophils, mast cells, neutrophils, macrophages, lymphocytes and plasma cells. Numerous pleomorphic, non-parallel walled, sparsely septate hyphae, characteristic of phycomycetes, were present within the collagen matrix. Colonies of gram-positive and gram-negative rods were also present within the lesion. This is the first description of FGESF with intralesional fungi.

Feline gastrointestinal eosinophilic sclerosing fibroplasia: 13 cases and review of an emerging clinical entity

Objective:

Feline gastrointestinal eosinophilic sclerosing fibroplasia (FGESF) is a recently described inflammatory disease of cats affecting stomach or intestines and draining regional lymph nodes. This study presents clinical and laboratory data on 13 newly described cases from Australia (11) and the UK (two).

Observations:

The disease was most often observed in middle-aged cats (median 7 years of age; interquartile range 5–9 years). Ragdolls (7/13) and males (9/13) were overrepresented. Cats generally had a long history of vomiting and/or diarrhoea. Lesions were typically large, hard, non-painful, easily palpable and most commonly situated near the pylorus or ileocaecocolic junction. Lesions were heterogeneous ultrasonographically and on sectioning at celiotomy or necropsy. Masses were hard and ‘gritty’ on fine-needle aspiration due to internal trabeculae made up of mature collagen bundles. Bacteria were commonly detected within masses (9/13 cases) using either culture or conventional light microscopy and a panel of special stains, and/or fluorescence in situ hybridisation (FISH), although detection often required a diligent search of multiple tissue sections. A consistent bacterial morphology could not be appreciated among the different cases.

Outcome:

Patients were treated with a variable combination of cytoreduction (debulking and biopsy, to complete surgical resection), immunosuppressive therapy and antimicrobial agents. Many cats had a poor outcome, which was attributable to late diagnosis combined with suboptimal management. It is hoped that suggestions outlined in the discussion may improve clinical outcomes and long-term survival in future cases.

Feline familial pedal eosinophilic dermatosis in two littermates

In cats, the most common eosinophilic dermatoses are feline miliary dermatitis and eosinophilic granuloma complex. The most commonly identified underlying cause is a hypersensitivity reaction. Few cases of familial forms of eosinophilic dermatoses are reported in the literature. Two young adult cats from the same litter presented 2 years apart with a severe and chronic fluid or tissue infiltration of the distal part of several limbs. Lesions started on the forelegs and developed on the other limbs. Cytological and histopathological examinations showed lesions consistent with an atypical form of feline eosinophilic dermatosis associated with secondary bacterial infection. In both cats, antibiotics combined with immunosuppressive treatment partially improved the lesions, which continued to progress on a waxing and waning course, even in the absence of treatment. Allergy work-up did not permit the identification of an underlying allergic triggering factor. The severity of the lesions, the unusual presentation and the unsatisfactory response to immunosuppressive therapy in two feline littermates suggested a genetic form of eosinophilic dermatosis.

Comparative immunology of allergic responses

Allergic responses occur in humans, rodents, non-human primates, avian species, and all of the domestic animals. These responses are mediated by immunoglobulin E (IgE) antibodies that bind to mast cells and cause release/synthesis of potent mediators. Clinical syndromes include naturally occurring asthma in humans and cats; atopic dermatitis in humans, dogs, horses, and several other species; food allergies; and anaphylactic shock. Experimental induction of asthma in mice, rats, monkeys, sheep, and cats has helped to reveal mechanisms of pathogenesis of asthma in humans. All of these species share the ability to develop a rapid and often fatal response to systemic administration of an allergen--anaphylactic shock. Genetic predisposition to development of allergic disease (atopy) has been demonstrated in humans, dogs, and horses. Application of mouse models of IgE-mediated allergic asthma has provided evidence for a role of air pollutants (ozone, diesel exhaust, environmental tobacco smoke) in enhanced sensitization to allergens.

Feline eosinophilic dermatoses: a retrospective immunohistochemical and ultrastructural study of extracellular matrix remodelling

BACKGROUND

Feline eosinophilic dermatoses (FEDs) are common diseases of cats with an unknown pathogenesis. They are histologically characterized by an eosinophilic infiltration and often by the presence of flame figures (FFs) and/or areas of loss of tissue architecture, here termed necrotic foci (NF). It has been postulated that an alteration in the degradation of the extracellular matrix could be responsible for these histological features. Matrix metalloproteinases (MMPs) are a group of proteases that are fundamental in extracellular matrix remodelling.

HYPOTHESIS/OBJECTIVES

The aim of the study was to investigate retrospectively the expression of a subgroup of MMPs, in particular MMP-2 and MMP-9 gelatinases, in FEDs. The expression of one of their inhibitors, TIMP-2, was also investigated in order to establish the role of these molecules in the pathogenesis of FEDs. The ultrastructural characteristics of extracellular matrix in FFs and NF were subsequently assessed.

METHODS

Fifty-one formalin-fixed, paraffin-embedded specimens from cutaneous and mucosal biopsies diagnosed as FEDs were investigated immunohistochemically. Two selected samples were processed for electron microscopy.

RESULTS

This study revealed an increased expression of MMP-2 in NF and a decreased expression of this gelatinase in FFs. An imbalance between MMP-2 and TIMP-2 was evident using immunohistochemistry. No significative results were observed for MMP-9 expression. Electron microscopy confirmed the lack of normal collagen fibres in NF, whereas in FFs only occasional, amorphous material was observed among normal collagen fibres.

CONCLUSIONS AND CLINICAL IMPORTANCE

Our study suggests that an imbalance in the expression of matrix metalloproteinases could be responsible for different morphological findings in FEDs. Further studies are needed to assess the role of matrix metalloproteinases in the pathogenesis of FEDs.

Dose tapering for ciclosporin in cats with nonflea-induced hypersensitivity dermatitis

BACKGROUND

Little information is available on the ciclosporin dose-tapering regimen and clinical response in the treatment of feline hypersensitivity dermatitis.

HYPOTHESIS/OBJECTIVES

To test a dose-tapering regimen and assess efficacy and clinical safety for up to 18 weeks.

ANIMALS

Eighty-eight client-owned cats with feline hypersensitivity dermatitis.

METHODS

Cats that received either a placebo or ciclosporin at 2.5 mg/kg or 7 mg/kg daily for 6 weeks were given 7 mg/kg ciclosporin daily for 4 weeks. Depending on the clinical response, the dose was tapered from daily to every other day over the next 4 weeks and further to twice a week for an additional 4 weeks.

RESULTS

After all cats received 7 mg/kg for 4 weeks, the dose could be tapered to every other day for the next 4 weeks in 70% of cats remaining in the study. During the next 4 weeks, 57, 15 and 22% of cats remaining in the study could be treated at twice a week, every other day or daily, respectively. After the first 4 weeks, the mean lesion score and owner-assessed pruritus improved over baseline by 69 and 61%, respectively, and remained stable during the following 8 weeks. Approximately 65% of the cats in the study were reported to have an adverse event (AE), very often mild and resolving spontaneously. The most frequent AEs were gastrointestinal and included primarily vomiting and diarrhoea. Eighty per cent of AEs occurred when cats were on daily treatment.

CONCLUSIONS AND CLINICAL IMPORTANCE

Results suggest that the induction dose of 7 mg/kg ciclosporin can be tapered as soon as 4 weeks without deterioration of the clinical response. Establishment of the lowest effective dosing regimen of ciclosporin reduced the frequency of AEs.

Feline Eosinophilic Granuloma Complex(ITIES)

Practical relevance: The feline eosinophilic granuloma complex (EGC) comprises a group of clinically well recognised but poorly understood dermatoses that are common in cats. In many cases, lesions are severe and can be accompanied by varying degrees of (and sometimes considerable) pruritus and/or pain. In addition, lesions can be chronic and recurrent. It is, therefore, important to achieve a prompt and accurate diagnosis in order to provide optimal, often life-long, treatment for affected cats.

Patient group: There is no age predisposition or well documented breed predilection for the development of EGC lesions in cats. Some studies have reported a possible female predisposition, but this has not been consistently documented.

Clinical challenges: The clinical diagnosis of EGC lesions is usually straightforward, but investigation of the potential underlying aetiology can pose a challenge for the clinician. Information on the indication for various diagnostic tests and their interpretation is lacking, and the tendency for these cases to be managed with chronic medical intervention prior to achieving a definitive diagnosis can further complicate the interpretation of any diagnostic investigation. In addition, successful therapeutic management of these cases can be challenging. Some cats suffer only a single episode of disease that resolves with treatment, while others have recurrent lesions and some of these can be refractory to treatment. The individual variation in both the clinical nature of the disease and the response to therapy could be related to disease severity, but could also be explained by differences in the underlying aetiopathogenesis.

Evidence base: This article reviews the published literature to discuss the complex aetiology of the EGC and present an overview of the different clinical presentations and diagnosis. A further and particular aim has been to provide some evidence-based recommendations for the management of this unusual group of dermatoses.

The use of ciclosporin A in veterinary dermatology

Ciclosporin A (CsA) has potent immunosuppressive and immunomodulatory activity that has been exploited in human medicine to prevent the rejection of transplanted organs and to manage atopic dermatitis and psoriasis. Over the past decade, CsA has been employed more frequently in veterinary dermatology and its value in the management of several canine and feline dermatoses is now well established. CsA inhibits calcineurin phosphatase, suppressing T cell activation and the synthesis of T cell cytokines consequently impairing the activity of B cells, antigen-presenting cells, mast cells, basophils and eosinophils. The pharmacokinetics of CsA are similar in humans, dogs and cats and the drug has a wide safety margin in dogs, cats and rabbits. Adverse effects, principally transient vomiting and soft faeces/diarrhoea, may be seen shortly after instituting treatment but often resolve despite continuing treatment. Gingival hyperplasia and cutaneous effects such as hirsutism may occur after prolonged treatment.

Immunohistological evaluation of feline herpesvirus-1 infection in feline eosinophilic dermatoses or stomatitis

This study used immunohistochemistry (IHC) and histopathology to evaluate the presence of feline herpesvirus-1 (FHV-1) in feline cases of 'eosinophilic granuloma complex' (EGC) or other eosinophilic dermatoses or stomatitis, diagnosed at the Veterinary Pathology Diagnostic Service, University of Sydney between January 1996 and June 2008. Two of the 30 cases (6.6%) examined showed positive immunoreactivity to FHV-1 using IHC. Intranuclear inclusion bodies were also detected on histopathological examination of haematoxylin and eosin stained sections of both cases but were very difficult to find. Therefore, FHV-1 is uncommonly associated with EGC or other eosinophilic dermatoses or stomatitis in Sydney. However, misdiagnosis as an EGC lesion or other eosinophilic dermatoses may occur if inclusion bodies are overlooked or absent on histopathology and this may significantly decrease the chance of a favourable treatment outcome. FHV-1 should be considered in cats with severe ulcerative cutaneous or oral lesions, unresponsive to corticosteroid treatment, with or without concurrent or historical signs of upper respiratory tract or ocular disease more typical of FHV-1. IHC may be helpful in differentiating FHV-1 dermatitis or stomatitis from other eosinophilic lesions, which is of vital clinical and therapeutic importance.

Feline Gastrointestinal Eosinophilic Sclerosing Fibroplasia

A retrospective study of cases of a unique intramural inflammatory mass within the feline gastrointestinal tract was performed in order to describe and characterize the lesion. Twenty-five cases were identified from archival surgical and postmortem tissues. The lesion most often occurred as an ulcerated intramural mass at the pyloric sphincter (n = 12) or the ileocecocolic junction or colon (n = 9); the remaining cases were in the small intestine. Seven cases also had lymph node involvement. The lesions were characterized by eosinophilic inflammation, large reactive fibroblasts, and trabeculae of dense collagen. Intralesional bacteria were identified in 56% of the cases overall and all of the ileocecocolic junction and colon lesions. Fifty-eight percent of cats tested had peripheral eosinophilia. Cats treated with prednisone had a significantly longer survival time than those receiving other treatments. We propose that this is a unique fibroblastic response of the feline gastrointestinal tract to eosinophilic inflammation that in some cases is associated with bacteria. The lesion is often grossly and sometimes histologically mistaken for neoplasia.