Discriminatory features of acute eosinophilic dermatitis with oedema (Wells-like syndrome) and sterile neutrophilic dermatosis (Sweet's-like syndrome) in dogs

A review of cutaneous hypersensitivity reactions in dogs: A diagnostician's guide to allergy

Allergic dermatoses are common in people and domestic animals. Resultant lesions are routinely biopsied and submitted for histological examination to confirm a diagnosis or rule out diseases with overlapping or atypical clinical features. Diagnostic pathologists and clinicians are often faced with the difficult task of determining whether an allergic reaction pattern is present on both the microscopic and macroscopic levels and correlating histopathologic findings with clinical and historical data to achieve a precise clinical diagnosis. The bulk of the current veterinary literature on allergic dermatoses focuses on atopic dermatitis in dogs, distantly followed by cats, horses, and other animals. The objectives of this review are to demonstrate the key histopathologic and clinical diagnostic features of the various allergy-mediated reaction patterns, and to provide diagnosticians with a practical guide for clinicopathological correlations. Current concepts in the pathophysiology of immediate hypersensitivity reactions, with a focus on atopic dermatitis, are discussed. Points of potential histopathologic overlap between the "classic" allergic reaction pattern and less common inflammatory, predominately eosinophilic, conditions that may mimic this pattern will be discussed with the goal of highlighting the critical need for collaboration between pathologists and clinicians in furthering patient care.

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.

Unilateral eosinophilic cellulitis leading to implant extrusion after bilateral enucleation in a dog

A mixed breed dog underwent bilateral enucleation with orbital implant placement for secondary glaucoma. Subsequent unilateral implant extrusion occurred. An orbital mass histologically consistent with eosinophilic cellulitis was discovered. It may have developed secondary to communication between orbit and skin. Inflammatory processes mimicking neoplasia can cause implant loss post‐enucleation.

Sterile neutrophilic dermatitis in a cat associated with a topical plant-derived oil flea preventative

A 4-year-old, female spayed, domestic short hair cat presented with an acute eruption of pustules and bullous plaques after application of a plant-based, essential oil flea preventative. Histopathological evaluation of biopsies revealed severe neutrophilic infiltrate within the dermis and culture was negative. The cat's skin lesions responded rapidly to glucocorticoid monotherapy.

Ulcerative neutrophilic dermatitis resembling human bromoderma in a dog

A dog was referred because of the presence of painful ulcers with violaceous borders and multiple dermal and subcutaneous haemorrhagic nodules on the bridge of the nose, on the dorsal aspect of the front paws, and on all four legs. Lesions had not responded to antibacterial and immunomodulatory therapy. Nine months earlier, the dog had been diagnosed with idiopathic epilepsy and treated with potassium bromide ever since. Histopathological examination of lesions revealed an interstitial neutrophilic dermatitis multifocally extending to the subcutaneous tissue. All special stains were negative for infectious agents, and due to the lack of tropism for follicular structures as well as negative bacterial and fungal cultures, a diagnosis of a sterile neutrophilic process similar to pyoderma gangrenosum was made. A cutaneous drug reaction was suspected, potassium bromide was suspended, and after 6 weeks the ulcerative lesions were completely healed. The present report describes a case of an ulcerative neutrophilic dermatitis presumed to be associated with administration of potassium bromide that resembled human bromoderma.

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

BACKGROUND

A dog with gastrointestinal signs and a history of administration of multiple drugs developed acute multifocal to coalescing ulcerative nodules and a large plaque.

OBJECTIVE

To describe abnormal nodular clinical lesions with an unexpected superficial and deep severe eosinophilic perivascular to interstitial inflammation.

ANIMAL

A 7-year-old spayed female Labrador retriever METHODS AND MATERIALS: Blood tests, faecal and urinalysis, and abdominal radiographs were performed; skin biopsy samples were taken for cytological, culture and histopathological analyses.

RESULTS

The blood tests, faecal, urinalysis and radiographs were within normal limits. Cytological results revealed inflammatory cells and cultures had no growth. Histopathological evaluation revealed dermal and subcutaneous oedema, mucin deposition and perivascular to interstitial inflammation predominated by eosinophils with occasional very small intralesional dense aggregates of eosinophils centred on collagen bundles, eosinophilic exocytosis and small eosinophilic pustules. Focal subepidermal fibrin exudation and haemorrhage resulted in epidermal detachment and ulceration. Clinical resolution of the dermatological and gastrointestinal signs was seen with the withdrawal of prior medications and administration of a tapering course of anti-inflammatory doses of prednisolone.

CONCLUSIONS AND CLINICAL IMPORTANCE

To the best of the authors' knowledge, this is a novel nodular clinical and eosinophilic histopathological pattern combination. This case offers evidence of a spectrum of sterile eosinophilic dermatoses rather than multiple different disease processes.