Dermoscopic features of benign sebaceous proliferations in dogs: Description, assessment and inter-observer agreement.

BACKGROUND: Dermoscopy is a useful, noninvasive technique also used to assess sebaceous lesions in humans. Sebaceous hyperplasia, sebaceous adenoma and sebaceous epithelioma are common cutaneous lesions in dogs; however, their dermoscopic features have not been investigated. HYPOTHESIS/OBJECTIVES: The objectives of this study are to describe the dermoscopic features of canine sebaceous lesions and to assess the interobserver agreement on dermoscopic parameters. ANIMALS: Thirty-four lesions excised from 17 client-owned dogs, histologically confirmed as sebaceous proliferations, were included in this study. MATERIALS AND METHODS: Sebaceous lesions were evaluated in vivo at ×10 magnification with a handheld dermoscope. Each dermoscopic image was assessed independently by two ECVD board-certified veterinary referral clinicians and an ECVD resident. RESULTS: Thirty sebaceous hyperplasias, two sebaceous adenomas and two sebaceous epitheliomas were included. Dermoscopically, most lesions (91%) had single or multiple, well-defined, white-yellowish structures composed of grouped ovoid areas (clods). Irregular linear and, less commonly, arborising vessels were detected at the periphery of the yellow lobular-like structures in 93% of sebaceous hyperplasias and in 50% of neoplastic lesions. Erosions were seen in 6% of sebaceous hyperplasias and 50% of neoplastic lesions. Good interobserver agreement was found for white/yellowish clods (k = 0.75), yellow scales (k = 0.83), brown/grey dots (k = 0.80), erosions (k = 0.82) and red/brownish scales/crusts (k = 0.75). There was moderate agreement for fissures (k = 0.48) and vascular pattern (k = 0.51-0.53). CONCLUSIONS AND CLINICAL RELEVANCE: Dermoscopy represents a useful technique to assess sebaceous gland proliferations in dogs, as it is in humans.

Clinical efficacy of sublingual allergen-specific immunotherapy in 22 cats with atopic dermatitis.

BACKGROUND: Sublingual immunotherapy (SLIT) has been deployed in humans and dogs; to the best of the authors' knowledge, there are no published studies about the use of SLIT in cats. OBJECTIVES: Evaluate the clinical efficacy of SLIT in atopic cats sensitized to dust and storage mites, assessing immunological changes associated with SLIT treatment. ANIMALS: Twenty-two client-owned cats with clinical signs compatible with feline atopic dermatitis (fAD) and serum allergen-specific immunoglobulin (Ig)E against house dust and storage mites. METHODS AND MATERIALS: Prospective, multicentre, open-label clinical trial. Individualized mite-specific SLIT was administered orally for 12 months. All cats underwent clinical examination to record SCORing feline allergic dermatitis (SCORFAD), pruritus Visual Analog Scale (pVAS) and serum allergen-specific IgE and IgG, every three months for 12 months. RESULTS: Sixteen of 22 cats (73%) completed the study and three of six cats withdrawn from the study were included in an intention-to-treat analysis. SCORFAD and pVAS values decreased significantly from baseline (T0) to the third month of treatment (P = 0.0004 and P = 0.0013, respectively), with median total values ranging from 19 (6-44) (T0) to 2.5 (0-17) (T12) (P = 0.0001), and from 8 (6-10) (T0) to 2.3 (0-8) (T12) (P = 0.0001), respectively. Allergen-specific IgE values decreased significantly from the ninth month (T9) of treatment (P = 0.0032), with median scores decreasing from 56 (12-729) (T0) to 34 (0-158) (T12) (P = 0.0208). No significant differences in allergen-specific IgG values were observed throughout the study. No adverse effects related to the use of SLIT were reported. CONCLUSIONS AND CLINICAL IMPORTANCE: Sublingual immunotherapy should be considered a rapid, effective, safe and well-tolerated treatment in cats with feline atopic dermatitis fAD.

Alopecia Areata in a Dog: Clinical, Dermoscopic and Histological Features.

Alopecia areata (AA)-like disease is characterized by multifocal patchy hair loss in humans, rodents, dogs, and horses. Remarkable similarities between human and nonhuman AA cases have been reported in terms of clinical presentation, histology, and immune mechanisms of the disease. Canine AA-like lesions most often consist of well-demarcated alopecic patches, frequently but not only involving the face and the head, which extend to the ear pinnae and legs. In some cases, hair loss can have a more generalized distribution. As in humans, hair regrowth is most commonly spontaneous in canine AA-like disease and the resistant cases usually respond to glucocorticoids or cyclosporine treatment. Diagnosis of AA in veterinary medicine relies on presentation, histopathology, and immunohistochemistry and on regrowth following therapy. This case report describes the first dermoscopic evaluation of AA-like disease in a dog with a clinical presentation of symmetrical hair loss.

Non-toxigenic Corynebacterium ulcerans sequence types 325 and 339 isolated from two dogs with ulcerative lesions in Italy.

Corynebacterium ulcerans, an emerging pathogen related to C. diphtheriae and C. pseudotuberculosis, is able to cause disease in both human and animal hosts. C. ulcerans may harbor acquired virulence factors such as dermonecrotic exotoxin phospholipase D (PLD) and the prophage-encoded diphtheria toxin (DT). Infections typically occur in persons reporting close contact with animals. In pets, C. ulcerans has been isolated from both asymptomatic carriers and clinically affected dogs and cats. We describe the isolation and characterization of C. ulcerans strains from 2 pet dogs with ulcerative lesions in Italy. The 2 isolates tested negative for both DT genes, but were PLD-producers and belonged to sequence types (STs) 325 and 339. These 2 cases highlight that C. ulcerans cutaneous infections might be underestimated in pets, given that many veterinary laboratories do not routinely consider and/or identify Corynebacterium species from cutaneous samples. Early detection and molecular typing of C. ulcerans is essential in order to implement effective treatment and to prevent diffusion and possible zoonotic transmission of certain STs.

Ultrasonography as a complementary diagnostic method for evaluating the skin of healthy cats.

Ultrasonography is not often used in feline dermatology. The purpose of this study was to assess the usefulness and applicability of ultrasonography for skin evaluation in 21 clinically healthy cats. Ultrasonographic examination was conducted in 4 cutaneous regions (frontal, dorsal neck, sacral, and abdominal) using an 18-MHz linear-sequential-array transducer. Findings were assessed using histomorphometric analysis of skin samples set as reference standards. Morphologic evaluation, thickness measurements, measurement variability, and comparison between regions and genders were carried out. The ultrasonographic pattern of feline skin was characterized by 3 distinct layers of different echogenicity and echostructure. Skin was thickest at the dorsal neck region and thinnest at the abdominal region. Skin at the frontal region and dorsal neck region was thicker in males. Variability was < 10% in all regions. No apparent correspondence was found between ultrasonographic and histometric measurements of skin thickness. Collectively, these findings suggest that ultrasonography is a simple, noninvasive, and reproducible technique that allows cutaneous layers to be identified and accurately measures skin thickness in cats.

L'échographie en dermatologie féline est actuellement peu utilisée. L'objectif de ce travail était d'estimer l'utilité et l'applicabilité de l'échographie pour l'évaluation de la peau chez 21 chats cliniquement sains. L'examen échographique a été effectué sur 4 régions cutanées (frontale, dorsale du cou, sacrée et abdominale) avec une sonde linéaire de 18 MHz. Les résultats ont été évalués en utilisant une analyse histomorphométrique établie comme référence standard. L'évaluation morphologique, les mesures d'épaisseur, la variabilité des mesures et la comparaison entre les régions et les sexes ont été effectuées. Le pattern échographique de la peau féline a été caractérisé par 3 couches distinctes pour échogénicité et échostructure différentes. La région dorsale du cou était la plus épaisse et l'abdominale la plus fine. Les régions frontale et dorsale du cou étaient plus épaisses chez le mâle. La variabilité était < 10 % en toutes les régions. Aucune correspondance apparente n'a été trouvée entre les mesures échographiques et histométrique. En général, ces résultats suggèrent que l'échographie représente une technique simple non invasive et reproductible, permettant d'identifier les couches cutanées et de mesurer l'épaisseur de la peau avec précision aussi chez les chats.(Traduit par les auteurs).

The usefulness of dermoscopy in canine pattern alopecia: a descriptive study.

BACKGROUND: Dermoscopic studies evaluating noninflammatory, nonpruritic progressive alopecia attributable to pattern alopecia are currently unavailable. HYPOTHESIS/OBJECTIVES: To evaluate the dermoscopic features observed in healthy skin of short coated dogs and compare these findings with those observed in dogs affected by pattern alopecia diagnosed by clinical and dermatopathological examination. ANIMALS: Thirty male and female, healthy, breed matched, young adult, short coated dogs (controls) and 30 male and female, young adult, short coated dogs affected by pattern alopecia. METHODS: Dermoscopy was performed with a Fotofinder II videodermoscope equipped with software that allowed the measurement of structures visualized in magnified images (20×-40×-70×). Skin biopsy samples were obtained from the thorax and evaluated dermoscopically for dermoscopic-histological correlation in affected dogs. RESULTS: Dermoscopic findings in canine pattern alopecia were hair shaft thinning, circle hairs and follicular keratin plugs; in the affected sun exposed areas there was a honeycomb-like pattern of pigmentation. Arborizing red lines reflecting vascularization were classified as a nonspecific finding because they were also common in healthy dogs. Dermoscopic features correlated with histology for selected hair follicle abnormalities. CONCLUSIONS AND CLINICAL IMPORTANCE: Although canine pattern alopecia is a visually striking disease, this study supports the value of dermoscopy for clinical examination and also opens promising perspectives for the identification of diagnostic dermoscopic patterns that may be useful for other skin disorders.

Rifampicin treatment of canine pyoderma due to multidrug-resistant meticillin-resistant staphylococci: a retrospective study of 32 cases.

BACKGROUND: Rifampicin has received increased interest in veterinary dermatology because of its activity against multidrug-resistant meticillin-resistant staphylococci (MRS). There is limited knowledge about the efficacy and safety of rifampicin in dogs. HYPOTHESIS/OBJECTIVE: To provide information on response to treatment and adverse effects in dogs treated with rifampicin for multidrug-resistant MRS pyoderma. ANIMALS: Thirty two dogs treated with rifampicin for rifampicin-susceptible multidrug-resistant MRS pyoderma. METHODS: Retrospective review of medical records, including alanine aminotransferase (ALT) and alkaline phosphatase (ALP) serum activity levels and total bilirubin concentrations, obtained before and throughout the treatment, was performed. RESULTS: Oral rifampicin as sole systemic antimicrobial therapy (median dose 5 mg/kg twice daily) was effective in 71.88% of cases. Topical antimicrobials were used in most cases. Median duration of rifampicin treatment was five weeks for superficial pyoderma and four weeks for deep pyoderma. Gastrointestinal signs were reported in 15% of treated dogs. Statistically significant increases of ALT (P = 0.045) and ALP (P = 0.0002) values after 3-4 weeks of treatment was observed. The median increase was equal to 0.3 and ×1.5 the upper limit of the reference ranges for ALT and ALP, respectively. CONCLUSIONS/CLINICAL IMPORTANCE: Oral rifampicin combined with topical antimicrobials can be considered an effective therapeutic option for canine superficial and deep pyoderma caused by rifampicin-susceptible multidrug-resistant MRS. Liver enzyme induction might be the most important cause of ALT and ALP increase associated with rifampicin therapy in dogs.

Evaluation of dermoscopy in the diagnosis of naturally occurring dermatophytosis in cats.

BACKGROUND: A rapid, accurate screening test for dermatophytosis in cats is desirable in clinical and shelter medicine. In human dermatology, dermoscopy is used to identify dermatophyte-infected hairs by their characteristic comma hair appearance. Similar "comma-like" hairs have been observed in infected cats. HYPOTHESIS/OBJECTIVES: The purpose of this study was to evaluate the usefulness of dermoscopy for the diagnosis of naturally occurring dermatophytosis compared to fungal culture. ANIMALS: A total of 67 cats were enrolled. METHODS: This was a descriptive field study. All cats were evaluated by dermoscopy and fungal culture. Dermoscopy was performed with a hand held nonpolarized light dermoscope. RESULTS: Three dermatophyte pathogens were isolated via fungal cultures in 36 cats: Microsporum canis (n = 31), Microsporum gypseum (n = 3) and Trichophyton mentagrophytes (n = 2). Dermoscopy was positive in 21 of 36 cats with culture-confirmed dermatophytosis. CONCLUSIONS AND CLINICAL IMPORTANCE: Dermoscopy may be a useful point-of care-test to identify infected hairs to sample for dermatophyte cultures, but a definitive diagnosis for dermatophytosis should be based on clinical signs and the results of multiple diagnostic tests.

Dermoscopic features in 12 cats with dermatophytosis and in 12 cats with self-induced alopecia due to other causes: an observational descriptive study.

BACKGROUND: Dermoscopy is a noninvasive technique allowing rapid magnified in vivo observation of the skin and structures that lie beneath the skin surface. Various congenital and acquired hair shaft abnormalities may also be evaluated by dermoscopy. Additionally, characteristic features of Microsporum canis-induced tinea capitis and trichotillomania in humans have been reported. OBJECTIVES: To describe the dermoscopic findings observed in cats with patchy alopecia due to M. canis infection and in cats with self-inflicted hair loss. ANIMALS: Twenty-four client-owned cats presented at a veterinary referral practice. METHODS: Dermoscopy was performed with a hand-held nonpolarized light dermoscope at 10-fold magnification. The glass plate of the dermoscope was applied gently to the lesions and no sedation was required. RESULTS: Twelve cats were diagnosed with dermatophytosis and 12 with self-induced alopecia due to other causes. At 10-fold magnification, the most characteristic findings observed in circumscribed lesions of cats with dermatophytosis were opaque, slightly curved, broken hairs of a homogeneous thickness (comma-like structures) and a variable amount of brown-to-yellow greasy scales. In cats with self-induced alopecia, multiple hairs with a normal shaft cleanly broken at different lengths, short tufts of hairs broken at an equal level and hook-like and coiled hairs were observed. CONCLUSIONS AND CLINICAL IMPORTANCE: This observational descriptive study suggests that dermoscopy may represent a helpful noninvasive in vivo technique in the differential diagnosis of patchy alopecia in cats.

Dermoscopic evaluation of skin in healthy cats.

BACKGROUND: Dermoscopy is a diagnostic tool that can reveal morphological structures not visible upon clinical examination. HYPOTHESIS/OBJECTIVES: To assess the usefulness and applicability of dermoscopy for the examination of healthy cat skin. ANIMALS: Twenty-one domestic short-haired cats from a feline rescue association. METHODS: Four regions (head, dorsal neck, sacral and abdominal regions) were examined with both a contact hand-held nonpolarized light dermoscope at 10-fold magnification and a videodermoscope at 70-fold magnification. Findings were assessed using histological analysis of skin samples cut both longitudinally and transversely, set as the gold standard. RESULTS: With a hand-held dermoscope at 10-fold magnification, thick, straight primary hairs surrounded by multiple secondary hairs were observed. With a videodermoscope at 70-fold magnification, hair shaft thickness was measured and the follicular openings and arrangement of vessels were clearly observed. Correspondence was observed between dermoscopic and histological results. CONCLUSIONS AND CLINICAL IMPORTANCE: Dermoscopy represents a valid noninvasive and reproducible technique that could be helpful in clinical examination.

Cytologic and immunocytochemical characterization of feline progressive histiocytosis.

BACKGROUND: Feline Progressive Histiocytosis (FPH) is a cutaneous dendritic cell neoplasm characterized by slow progression and spread to internal organs in the terminal stage. FPH is often misdiagnosed as an inflammatory reaction and has not been fully characterized from a cytologic diagnostic perspective. OBJECTIVES: The purpose of the study was to characterize the cytologic and immunocytochemical aspects useful for FPH diagnosis. METHODS: Fine-needle aspiration cytologic samples of 5 cases of FPH confirmed by skin biopsy and necropsy were evaluated. Immunocytochemistry with antibodies recognizing CD1a, CD1c, CD3, CD11b, CD18, CD21, and MHCII was performed on air-dried, acetone-fixed smears. E-cadherin expression was assessed on paraffin-embedded skin biopsies. Transmission electron microscopy (TEM) was performed in one case. RESULTS: Main cytologic findings on variably cellular samples were characterized by single to cohesive large, round to polygonal cells with intermediate to low N/C ratio, abundant clear homogeneous cytoplasm, and round to oval nuclei with rare bi- to multinucleated atypical cells, associated with low numbers of small lymphocytes and/or neutrophils. Neoplastic cells expressed CD1a, CD1c, CD11b, CD18, and MHCII. Anti-CD3 antibodies identified reactive T cells admixed with the neoplastic cells. E-cadherin expression was observed in all but one case. TEM failed to identify Birbeck granules in one case. CONCLUSIONS: FPH is a distinctive neoplastic lesion composed of nonphagocytizing histiocytes variably admixed with neutrophils and small mature lymphocytes. Immunocytochemical analysis with CD1 is mandatory to confirm a dendritic cell origin. Immunocytochemistry and cytomorphology allowed the specific and rapid diagnosis of FPH on cytologic samples.

Dermatophytosis and papular eosinophilic/mastocytic dermatitis (urticaria pigmentosa-like dermatitis) in three Devon Rex cats.

UNLABELLED: PRESENTING SIGNS: Three Devon Rex cats were presented with multiple erythematous papules, occasionally associated with crusting and hyperpigmentation, with a linear distribution on the head, neck, chest and abdomen. One cat also had multifocal alopecia with hyperpigmentation on the dorsum. DIAGNOSIS AND TREATMENT: Clinical and histopathological features were suggestive of papular eosinophilic/mastocytic dermatitis (urticaria pigmentosa-like dermatitis). In all cases, dermatophytosis was diagnosed: in cases 1 and 2 there was histopathological evidence of dermatophytosis, while fungal culture was positive for Microsporum canis in cases 2 and 3. In all cats, lesions disappeared following antifungal treatment. CLINICAL SIGNIFICANCE: Papular eosinophilic/mastocytic dermatitis in Devon Rex cats may represent either an atypical presentation of dermatophytosis or a clinical and histological reaction pattern to various diseases, including dermatophytosis and allergic diseases. Clinical differentiation is crucial as there are important implications regarding treatment and, in particular, the use of glucocorticoids, which are contraindicated in cases of dermatophytosis.

Evaluation of the bacterial microflora of the conjunctival sac of healthy dogs and dogs with atopic dermatitis.

The aim of this case-control study was to evaluate and compare the bacterial microflora from the conjunctival sac of dogs with atopic dermatitis and healthy dogs. Twenty-one atopic dogs without clinical and/or cytopathological signs of bacterial blepharoconjunctivitis and 21 breed-matched healthy dogs were enrolled. Under topical anaesthesia, the inferior conjunctival sac of one eye was scraped twice. Material was collected with a Kimura spatula, spread over a slide and stained with a Diff Quick(®) -type stain (Medion Diagnostics GmbH, Düdingen, Switzerland) for cytological examination. An area of 0.5 cm(2) was examined at ×1000 magnification, and the types and numbers of cells and bacteria were recorded. A bacterial swab was collected and inoculated into culture media for the growth of aerobic bacteria. Before sampling, each atopic dog was evaluated for severity of cutaneous lesions, pruritus and conjunctival inflammation. Significant differences were observed between atopic and healthy dogs for the presence of bacteria on cytology (P = 0.015), keratinized (P = 0.001) and nonkeratinized epithelial cells (P = 0.013), eosinophils (P = 0.019) and lymphocytes (P = 0.008). Bacteria were recovered from 12 atopic dogs and three healthy dogs (P = 0.004). Staphylococcus pseudintermedius was the most commonly isolated species in atopic dogs (seven of 12). In atopic dogs, no significant relation was found between conjunctival bacterial colonization (on cytology and culture) and the severity of any of the clinical parameters. This study suggests differences in conjunctival bacterial colonization and cytological features between atopic and healthy dogs.

Prevalence of Demodex canis-positive healthy dogs at trichoscopic examination.

Demodex canis is thought to be present in small numbers in the skin of most healthy dogs; however, available data on the prevalence of normal dogs harbouring D. canis are scarce. The purpose of this study was to investigate, using microscopic examination of plucked hairs, the prevalence of healthy dogs harbouring D. canis. Seventy-eight clinically healthy dogs with no history of dermatological problems and clinically normal skin and hair coat were included in the study. Five areas (perioral skin 2-3mm from both labial commissures, periungual skin of the third digit of both anterior paws and chin) were examined in each dog. Fifty to sixty hairs were plucked from each skin site and microscopically examined. No D. canis mites were observed and only one adult form of Demodex injai was found in the labial commissure of one dog. Based on these results, the estimated prevalence of healthy dogs harbouring D. canis in clinically normal skin should not exceed the threshold of 5.4%, with 95% confidence level. Considering our and previous findings, we propose that, although small numbers of D. canis might inhabit the skin of normal dogs, the probability of finding these mites in normal dogs is low. Consequently, in most cases, the presence of a D. canis mite in the skin should not be considered as indicative of normality.

Demodex injai infestation and dorsal greasy skin and hair in eight wirehaired fox terrier dogs.

Demodex injai mites were detected on trichoscopic examinations and/or deep skin scrapings in eight wirehaired fox terrier dogs with dorsal greasy skin and hair. Histological examination performed in five dogs revealed marked sebaceous gland hyperplasia with lympho-plasmacytic periadnexal dermatitis in all of them. One mite section was observed in one patient. Seven dogs were parasitologically cured after 2 to 7 months of oral ivermectin treatment. Greasy skin and hair resolved in four dogs, was partially reduced in two dogs and persisted in the remaining dog. Skin biopsies were repeated after parasitological cure in two dogs and revealed the persistence of sebaceous gland hyperplasia with mild lympho-plasmacytic periadnexal dermatitis and no parasites. Based on the findings in this case series, the terrier dog breed might be at increased risk for the development of D. injai mite infestation associated with dorsal greasy skin and hair, and microscopically with sebaceous gland hyperplasia. Persistence of sebaceous gland hyperplasia after parasitological cure in some patients suggested that this histological finding may not always be resulting from Demodex infestation. Moreover, low numbers of adult mites and variable clinical responses to acaricidal therapy suggested a contributory rather than a major role of D. injai in this skin condition. Dermatopathological diagnosis of sebaceous gland hyperplasia, particularly in case of dorsal trunk specimens from terrier dog breeds, warrants the search for D. injai mites on trichoscopic examinations and/or deep skin scrapings.

Malassezia spp. overgrowth in allergic cats.

A series of 18 allergic cats with multifocal Malassezia spp. overgrowth is reported: atopic dermatitis was diagnosed in 16, an adverse food reaction in another and one was euthanized 2 months after diagnosis of Malassezia overgrowth. All the cats were otherwise healthy and those tested (16 out of 18) for feline leukaemia or feline immunodeficiency virus infections were all negative. At dermatological examination, multifocal alopecia, erythema, crusting and greasy adherent brownish scales were variably distributed on all cats. Cytological examination revealed Malassezia spp. overgrowth with/without bacterial infection in facial skin (n = 11), ventral neck (n = 6), abdomen (n = 6), ear canal (n = 4), chin (n = 2), ear pinnae (n = 2), interdigital (n = 1) and claw folds skin (n = 1). Moreover, in two cats Malassezia pachydermatis was isolated in fungal cultures from lesional skin. Azoles therapy alone was prescribed in seven, azoles and antibacterial therapy in eight and azoles with both antibacterial and anti-inflammatory therapy in three of the cats. After 3-4 weeks of treatment, substantial reduction of pruritus and skin lesions was observed in all 11 cats treated with a combined therapy and in five of seven treated solely with azoles. Malassezia spp. overgrowth may represent a secondary cutaneous problem in allergic cats particularly in those presented for dermatological examination displaying greasy adherent brownish scales. The favourable response to treatment with antifungal treatments alone suggests that, as in dogs, Malassezia spp. may be partly responsible for both pruritus and cutaneous lesions in allergic cats.

Papular eosinophilic/mastocytic dermatitis (feline urticaria pigmentosa) in Devon Rex cats: A distinct disease entity or a histopathological reaction pattern?

A maculopapular eruption with clinical and histological features similar to those previously described in Sphinx cats under the name of urticaria pigmentosa is reported in five unrelated Devon Rex cats. Physical examination revealed erythematous, occasionally crusted papules, with a bilaterally symmetrical linear distribution on the latero-ventral trunk in two cases and a diffuse distribution on the ventral thorax in the other three cats. One cat also had a greasy seborrhoea on the head and dorsum. Pruritus and pigmented macules were present only in cats affected by secondary bacterial infection. Histological examination of papules in all cats and of the lesional skin of the cat affected by greasy seborrhoea revealed the presence of a perivascular to diffuse mastocytic and eosinophilic infiltrate in the dermis. The mean numbers of nondegranulated and degranulated mast cells per mm(2) were 303.2 and 451.6, respectively. The condition waxed and waned in all cats, and exacerbations were controlled with prednisolone or essential fatty acids.

Linear organoid nevus in a dog.

A skin lesion classified as linear organoid nevus is reported in a female standard Schnauzer. The dog was brought to the clinic with multiple hyperpigmented, hyperkeratotic linear or ovoid plaques on the head, neck, trunk, ears, and limbs. Histological findings included severe orthokeratotic hyperkeratosis, focal parakeratosis and hyperplasia of both the epidermis and the follicular infundibular epithelium, and marked sebaceous hyperplasia. No improvement was noted with systemic retinoid therapy. This is the second linear organoid nevus described in a dog, and the first report of retinoid therapy for this disease.