A case of metabolic epidermal necrosis in a cat

Biology, diagnosis and treatment of Malassezia dermatitis in dogs and cats Clinical Consensus Guidelines of the World Association for Veterinary Dermatology

BACKGROUND

The genus Malassezia is comprised of a group of lipophilic yeasts that have evolved as skin commensals and opportunistic cutaneous pathogens of a variety of mammals and birds.

OBJECTIVES

The objective of this document is to provide the veterinary community and other interested parties with current information on the ecology, pathophysiology, diagnosis, treatment and prevention of skin diseases associated with Malassezia yeasts in dogs and cats.

METHODS AND MATERIAL

The authors served as a Guideline Panel (GP) and reviewed the literature available prior to October 2018. The GP prepared a detailed literature review and made recommendations on selected topics. The World Association of Veterinary Dermatology (WAVD) Clinical Consensus Guideline committee provided guidance and oversight for this process. The document was presented at two international meetings of veterinary dermatology societies and one international mycology workshop; it was made available for comment on the WAVD website for a period of six months. Comments were shared with the GP electronically and responses incorporated into the final document.

CONCLUSIONS AND CLINICAL IMPORTANCE

There has been a remarkable expansion of knowledge on Malassezia yeasts and their role in animal disease, particularly since the early 1990's. Malassezia dermatitis in dogs and cats has evolved from a disease of obscurity and controversy on its existence, to now being a routine diagnosis in general veterinary practice. Clinical signs are well recognised and diagnostic approaches are well developed. A range of topical and systemic therapies is known to be effective, especially when predisposing factors are identified and corrected.

Metabolic epidermal necrosis in a dog associated with pancreatic adenocarcinoma, hyperglucagonaemia, hyperinsulinaemia and hypoaminoacidaemia

A case of metabolic epidermal necrosis associated with a pancreatic carcinoma is described. Normoglycaemia, reduced serum fructosamine, and hypoaminoacidaemia were identified. Hyperinsulinaemia and hyperglucagonaemia were documented. Immunohistochemistry documented strong tumour expression of both insulin and glucagon supporting combined paraneoplastic production of both hormones by the tumour. Enteral protein and fatty acid supplementation and parenteral amino acid supplementation proved ineffective. Metastasis to regional lymph nodes was identified and the patient was euthanased.

Cutaneous paraneoplastic syndromes in dogs and cats: a review of the literature

Cutaneous paraneoplastic syndromes are a group of noncancerous dermatoses associated with internal malignancy. Their recognition can facilitate detection and timely treatment of underlying cancer. More than 30 such disorders have been identified in the human scientific literature, whereas only a few are described in veterinary medicine. This may reflect a lower incidence in animals than in people or may be the result of failure to recognize an association between certain skin lesions and neoplasia. Establishing a relationship between a cutaneous disorder and neoplasia can be difficult unless the skin lesions are rare and almost always associated with a particular tumour type, as is the case for most recognized veterinary paraneoplastic dermatoses. Among these are feline paraneoplastic alopecia, feline thymoma-associated exfoliative dermatitis, nodular dermatofibrosis, feminization syndrome associated with testicular tumours, superficial necrolytic dermatitis and paraneoplastic pemphigus. The aetiology of most cutaneous paraneoplastic syndromes has remained elusive in both people and animals.

Clinicopathological, ultrasonographic, and histopathological findings of superficial necrolytic dermatitis with hepatopathy in a cat

This report describes the antemortem diagnosis and antemortem and postmortem findings of superficial necrolytic dermatitis with hepatopathy (i.e., hepatocutaneous syndrome) in a cat. A 5-year-old Maine coon was evaluated because of a history of pruritic alopecia and liver enzyme elevations. Abdominal ultrasonography revealed a reticular pattern to the hepatic parenchyma. Histopathological findings of the liver were nodular regeneration with bands of vacuolated hepatocytes and bile duct hyperplasia, characteristic of the hepatopathy frequently associated with superficial necrolytic dermatitis. Skin histopathology revealed multifocal parakeratosis, midepidermal spongiosis, and basal cell hyperplasia consistent with superficial necrolytic dermatitis.

Plasma amino acid concentrations in 36 dogs with histologically confirmed superficial necrolytic dermatitis

Plasma amino acid concentrations were measured in 36 dogs diagnosed with superficial necrolytic dermatitis (SND) via skin biopsy. The median age of the dogs was 10 years, and 27 out of 36 (75%) were male. Twenty-two out of 36 (61%) of the dogs were accounted for by six breeds; West Highland white terriers (six), Shetland sheepdogs (five), cocker spaniels (four), Scottish terriers (three), Lhasa apsos (two) and Border collies (two). The mean concentration (+/- standard deviation) was calculated for each measured plasma amino acid and compared to previously documented concentrations of plasma amino acids measured in dogs with acute and chronic hepatitis. The ratio of branched chain amino acids to aromatic amino acids in the dogs with SND was 2.6, slightly lower than that in normal dogs. The mean plasma amino acid concentrations for dogs with SND were significantly lower than for dogs with acute and chronic hepatitis. A metabolic hepatopathy in which there is increased hepatic catabolism of amino acids is hypothesized to explain the hypoaminoacidaemia seen in SND.

Retrospective study: the presence of Malassezia in feline skin biopsies. A clinicopathological study

Malassezia spp. dermatitis, a rare disorder in cats, has previously been associated with immune suppression and internal malignancies. This study evaluates the presence and importance of Malassezia spp. in feline biopsy specimens submitted for histopathological examination. Five hundred and fifty haematoxylin and eosin-stained skin biopsy specimens received for histopathological examination between January 1999 and November 2000 were reviewed. Fifteen (2.7%) submissions contained Malassezia organisms in the stratum corneum of the epidermis or follicular infundibulum. Eleven of 15 cats presented with an acute onset of multifocal to generalized skin lesions. All 11 cats were euthanized or died within 2 months of the onset of clinical signs. Seven cats had dermatopathological changes and clinical signs supportive of paraneoplastic alopecia, and three cats had an interface dermatitis suggestive of erythema multiforme or thymoma-associated dermatosis. Histopathological changes were nonspecific in one cat that was euthanized 2 weeks following onset of severe pruritus and alopecia. In three cats, Malassezia spp. were found in localized sites (two chin, one footpads) and appeared inconsequential to their overall health status. One cat had Malassezia spp. in association with cutaneous demodicosis. These findings suggest that Malassezia yeast in dermatopathological specimens from multifocal or generalized lesions should prompt a thorough clinical work-up for internal neoplasia.

Suspected necrolytic migratory erythema associated with chronic hepatopathy in a cat

A cat presenting with generalised hypotrichosis and crusts on the feet and tail was found to have an unusual chronic hepatopathy. There was also evidence of a chronic small intestinal disease which went undiagnosed. Necrolytic migratory erythema was suspected based on clinical findings and dermatohistopathology, and an association with the chronic hepatopathy was suggested. This is the first report of such an association in a cat. Serum zinc, amino acids and essential fatty acids were analysed, and medical treatment was given with equivocal efficacy.

Metabolic epidermal necrosis-hepatocutaneous syndrome

It is clear that cutaneous lesions of metabolic epidermal necrosis in the dog can occur either with a demonstrable glucagon-secreting tumor or with hepatic disease without any detectable glucagonoma. Additional clinical case reports of the disease in cats are needed to better characterize the disease in this species. The lesions of NME-MEN may not represent a specific physiological mechanism of cutaneous disease but instead a pathophysiological process that can be triggered by several systemic metabolic abnormalities. The fact that NME is observed in association with a variety of conditions supports the theory that an overall metabolic derangement results in the rash. The prognosis for canine MEN is poor; however, some affected dogs have been maintained for many months with dietary management. High-quality protein diets such as Hill's Prescription Diet a/d (Hill's Pet Products) or other "recovery" diets may be helpful. Zinc and essential fatty acid supplementation may help some patients. Dietary supplementation with cooked egg yolks may be helpful. It is prudent to avoid corticosteroids in these cases, as development of diabetes mellitus worsens the prognosis. Histopathological examination of the pancreas coupled with determination of plasma glucagon may help define the characteristics of GS versus HS in dogs. It is possible that some dogs diagnosed with MEN-HS may have an undetected pancreatic tumor. Although the hepatic ultrasound findings in dogs with MEN-HS are becoming well characterized, it is possible for dogs with pancreatic neuroendocrine tumors to also have abnormal hepatic ultrasonography. As the presence of MEN and hepatic disease does not necessarily rule out the presence of a pancreatic tumor, prospective studies correlating plasma glucagon levels with pancreatic histopathology in cases of MEN-GS versus MEN-HS seem warranted.

A case of feline paraneoplastic alopecia with secondary Malassezia-associated dermatitis

A 13-year-old neutered female domestic shorthaired cat had progressive ventral abdominal alopecia attributed initially to hyperthyroidism. Corrective treatment by unilateral thyroidectomy did not, however, resolve the dermatosis and the alopecia progressed to involve the whole ventral trunk, the lower limbs and the head. Pruritus of the lower limbs was a prominent feature and was associated with the finding of Malassezia on cytology; Malassezia-associated dermatitis was diagnosed. Resolution of pruritus was seen after treatment with oral ketoconazole and a cleansing shampoo to eliminate the yeast, but severe polyphagia, small intestinal diarrhoea and polydipsia developed subsequently and the cat was euthanased. Necropsy revealed an exocrine pancreatic adenocarcinoma with hepatic metastases. The pancreatic, hepatic and dermatological lesions were found to be typical of feline paraneoplastic alopecia (FPA). Malassezia-associated dermatitis can be associated with pruritus in cats with FPA.