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.

A case series of canine cutaneous inverted papilloma with one case showing evidence of recurrence

BACKGROUND

This article describes a case of multiple, recurrent, cutaneous inverted papillomas (CIPs) in a German shepherd dog, combined with a retrospective follow-up assessment of eight cases.

METHODS

A 3-year-old, black, female German shepherd dog presented with four rapidly growing, alopecic, domed, hyperpigmented, shiny nodules, compatible with CIP. The dog was managed for pruritus, associated with atopic dermatitis, with long-term prednisolone therapy and this therapy was continued after the surgical excision. Twelve months after the initial presentation the dog was represented for two new CIP lesions, coinciding with an increased dosage of prednisolone during an allergic flare-up period.

RESULTS

Histopathological evaluation was conducted on both the original and subsequent lesions from the case with recurrence. Eight cases of CIP, based on histopathological findings, were identified retrospectively from the authors' diagnostic pathology service over the previous two years. All nine cases had lesions that exhibited varying degrees of inverted epithelial hyperplasia, multiple, endophytic, papillary epidermal projections, a cup-shaped base with central hyperkeratosis and active viral pathological findings (koilocytes). The submitting veterinarians were contacted and follow-up regarding recurrence and concurrent medications was obtained.

CONCLUSIONS AND CLINICAL IMPORTANCE

CIP is uncommonly reported, typically as a single lesion with no previous reports of recurrence, although one group of dogs with severe combined immunodeficiency developed invasive malignancies. In seven of eight retrospective cases no recurrence of CIP was recorded. The authors speculate that the recurrence in the German shepherd dog may have been associated with chronic (although low-dose) glucocorticoid administration.

Hair follicle dystrophy in a litter of domestic cats resembling lanceolate hair mutant mice

BACKGROUND

A new congenital hair-shaft abnormality resembling the lanceolate hair phenotype of rodents is described in a litter of four domestic short hair (DSH) cats. Data relating to hair shaft and follicle disorders remain scarce in veterinary medicine.

OBJECTIVES

To describe and compare structural abnormalities in these cats with other hair dystrophies in cats and other mammals.

ANIMALS

A DSH cat litter with progressive noninflammatory alopecia.

METHODS AND MATERIALS

Histopathological evaluation, scanning and transmission electron microscopy, and X-ray based element analysis defined the hair and skin changes in cats born with alopecia. Findings were compared to archival data from normal cats and lanceolate hair (Dsg4lahJ ) and Keratin 75 (Krt75tm1Der ) mutant mice.

RESULTS

Light and scanning electron microscopy of the hairs revealed lance- or spear-head shaped defects of the hair tip. Histological findings were swollen hair shafts, initially above the hair bulb matrix and later found in the distal parts of the telogen hair follicles, similar to those observed in Dsg4lahJ Krt75tm1Der mutant mice. Transmission electron microscopy of the hair shaft and hair follicles showed a loss in the normal structure of the guard hairs in the alopecic cats. There was a statistically significant decrease in sulfur content just below the defects in the hair shafts (trichothiodystrophy).

CONCLUSION AND CLINICAL IMPORTANCE

A rare form of congenital alopecia resulting in follicular dystrophy is described in cats which is similar to hair follicle and hair-shaft changes reported in several mutant mouse strains with single gene mutations in adhesion molecules or keratin genes.

Feline cowpoxvirus infections in Germany: clinical and epidemiological aspects

Clinical and epidemiological aspects of cats with cowpox in Germany from the years 2004 to 2010 are described and discussed. Questionnaires were sent to veterinarians and owners of affected cats identified with the help of a number of pathology laboratories. Of 69 mailed questionnaires, 45 veterinary and 26 owner questionnaires were returned and a total of 46 feline poxcases were evaluated. The cases were distributed all over Germany although there was an accumulation of cases in specific geographic areas. The clinical and epidemiological observations match those of other studies. The majority of cats were outdoor cats, came from a rural environment and developed clinical signs in late summer or autumn. All cats showed skin lesions which were predominantly localized on the anterior part of the body, 61% of the cats showed other clinical signs in addition to the skin lesions. Approximately half of the cats lived in a multi-pet household, but in only one case clinical signs typical for cowpox were observed in another cat of the household. In two cases a cat-to-human transmission was assumed. In addition, to evaluate the prevalence of pox virus infections in outdoor cats in areas with previous reports of such infections, 92 apparently unaffected outdoor cats were tested for orthopoxvirus antibodies using an indirect immunofluorescence assay. Sixteen (17%) of the tested serum samples were seropositive against orthopoxvirus (titre between 1:20 and 1:40).This is a higher serum prevalence than in previously published studies from Germany. A possible explanation is selection of a population of outdoor cats from regions with previous known clinical cases.

Hereditary equine regional dermal asthenia ('hyperelastosis cutis') in 50 horses: clinical, histological, immunohistological and ultrastructural findings

Data on fifty horses with hereditary equine regional dermal asthenia (HERDA; "hyperelastosis cutis") were collected on clinical, histopathological, ultrastructural and immunohistological findings. All horses were Quarter horses or of Quarter horse ancestry. Pedigree evaluation strongly supported an autosomal recessive mode of inheritance. The most common lesions were seromas/haematomas, open wounds, sloughing skin, and loose, easily tented skin that did not return to its initial position. Definitive diagnosis could not be made via histopathology, although the presence of tightly grouped thin and shortened collagen fibres arranged in clusters in the deep dermis was suggestive of the disease. Trichrome, acid orcein-Giemsa and immunohistochemical stains for collagens I and III showed no consistent abnormalities compared to control horses; an increase in elastic fibres was not a consistent finding. Electron microscopy showed no abnormalities in the periodicity of the collagen bundles; neither orientation nor variation of cross-section diameter of the collagen fibrils differentiated control from affected horses. The diagnosis of HERDA relies on clinical presentation, but may be supported by suggestive (although not pathognomonic) histopathological lesions.