Microbiology of normal and seborrheic canine skin.

Quantitative and qualitative bacterial assays were performed on the skin of 15 normal and 32 seborrheic dogs. Nonionic detergent scrubs were made on areas demarcated by glass sidearm cylinders. Quantitative analysis was accomplished by the serial dilution technique, and the bacteria were identified by individual and colonial morphology and by enzyme production. Areas measured on control dogs had a markedly lower total bacterial count than similar areas measured on seborrheic animals. Control dogs had a flora consisting primarily of coagulase-negative cocci, whereas seborrheic dogs usually had a cutaneous flora composed primarily of Stahylococcus aureus, coagulase-positive.     

Regional distribution of ten common skin diseases in dogs

We investigated the regional distributions of the most commonly diagnosed skin diseases in dogs from 17 North American veterinary teaching hospitals. Between January 1983 and December 1983, 11,456 diagnoses of skin disease were made. The 10 most common diagnoses were fleabite allergic dermatitis, skin cancer, pyoderma, seborrhea, allergy, demodectic acariasis (demodicosis), sarcoptic acariasis, immune-mediated skin disease, endocrine related skin disease, and acral lick dermatitis. Regional differences in the frequency of skin diseases were apparent. The northeast region had high frequencies of fleabite allergic dermatitis, allergy, and immune-mediated disease, and a low frequency of seborrhea. The midwest had a high frequency of seborrhea, and low frequencies of demodectic acariasis and allergy. In the plains region, low frequencies of fleabite allergic dermatitis, pyoderma, seborrhea, allergy, and demodectic acariasis were detected. In the west, the frequencies of fleabite allergic dermatitis, skin cancer, pyoderma, seborrhea, and acral lick dermatitis were high, whereas few dogs had allergic disease and sarcoptic acariasis. The southwest had high frequencies of fleabite allergic dermatitis and demodectic and sarcoptic acariasis. Fleabite allergic dermatitis, pyoderma, and demodectic and sarcoptic acariasis were frequently diagnosed in the southeast, but the number of dogs with seborrhea was low.     

Papular dermatitis due to Leishmania spp. infection in dogs with parasite-specific cellular immune responses

Papular dermatitis due to Leishmania spp. infection was diagnosed in three boxers and two Rottweilers with Leishmania-specific cellular immunity. Diagnosis was based on histological and immunohistochemical examination of papules in four dogs and on cytological examination in one dog. Serum protein electrophoresis was within reference ranges and low antibody levels to Leishmania infantum were detected. Delayed-type hypersensitivity (DTH) reaction to leishmanin was evaluated before treatment in three dogs with positive results. After meglumine antimoniate therapy for 3 to 4 weeks and allopurinol treatment for 6 to 10 months, all dogs were clinically normal, had positive DTH reactions to leishmanin and reduced antibody titres. In conclusion, we suggest that this previously unreported cutaneous presentation of canine leishmaniosis appears to be associated with specific immunocompetence and, consequently, with a favourable prognosis.     

Total hemolytic complement values in normal and diseased dog populations

The optimum conditions for handling and storage of canine sera for total hemolytic complement assays were assessed. Sera from 113 normal dogs and 217 clinical admissions to the University of Pennsylvania Veterinary Hospital were assayed for total hemolytic complement levels. Normal sera had a mean value of 185 CH50 units. Sera from animals with systemic lupus erythematosus and hemorrhagic gastroenteritis, had significantly lower mean levels of complement than the normal group. Sera from dogs with generalized demodectic mange, tumors, various inflammatory diseases, hypothyroidism, seborrhea, and rheumatoid arthritis had values significantly higher than the normal population.     

Impact of tumour depth, tumour location and multiple synchronous masses on the prognosis of canine cutaneous mast cell tumours

The goal of this study was to determine the significance of tumour depth, tumour location and multiple synchronous tumour masses for the prognostic evaluation of canine cutaneous mast cell tumours (MCTs). The study population consisted of 100 formalin-fixed, paraffin-embedded cutaneous MCTs that had been surgically removed from 100 dogs and submitted to the Diagnostic Center of Population and Animal Health at Michigan State University between 1998 and 2001. None of the dogs had received chemotherapy or radiation therapy. For each case the following data were obtained from the referring veterinarians: sex, breed, weight, age at diagnosis, diagnostics performed, adjunct medications given at the time of surgery, tumour location, number of tumour masses, tumour recurrence (development of MCTs at the surgical site), development of additional MCTs at distant sites (outside the surgical margins), tumour duration before removal, survival time and cause of death, if applicable. Tumour depth was determined through microscopic evaluation of 5 microm sections stained with haematoxylin and eosin. Based on univariable and multivariable survival analysis, dogs with multiple synchronous cutaneous MCTs at the time of diagnosis have a worse prognosis compared with dogs with single tumours. Additional treatment beyond surgical excision alone should be considered for these animals. Older dogs and Boxers with cutaneous MCTs were at higher risk to develop additional MCTs at distant sites (outside the surgical margins), and older and male dogs with cutaneous MCTs had significantly shorter survival times. Univariable analysis also determined that dogs with cutaneous MCTs located on the head and neck had an increased risk of additional MCT development at distant sites and that sterilized dogs with cutaneous MCTs had shorter survival times. However, these findings were not confirmed by multivariable analysis. Tumour depth was of no prognostic significance for dogs with cutaneous MCTs.     

Cutaneous antimicrobial preparation prior to intravenous catheterization in healthy dogs: clinical, microbiological, and histopathological evaluation.

The purpose of this study was to determine the effects of a one-minute chlorhexidine gluconate skin preparation protocol prior to cephalic vein catheterization. Twenty-three healthy beagle dogs had one leg aseptically prepared and the opposite leg served as a control. Twenty-six- and 77-hour time groups were studied. Chlorhexidine-treated legs had significantly lower cutaneous bacterial counts than the control legs prior to catheter insertion and prior to catheter withdrawal for both time groups. Control legs developed significantly more dermatitis than the treated legs after 77 h. A one-minute preparation with 4% chlorhexidine gluconate was an effective method for sustained reduction of cutaneous bacterial counts at peripheral intravenous catheter insertion points in dogs. Increased cutaneous bacterial counts were associated with significantly more microscopic dermatitis in untreated legs after 77 h of catheterization.     

CCNU in the treatment of canine epitheliotropic lymphoma

This retrospective study examined the use of CCNU (1-[2-chloroethyl]3-cyclohexyl-1-nitrosurea) in 36 dogs with epitheliotropic lymphoma. Thirty-one (86%) dogs had the cutaneous form of disease, and 5 (14%) dogs had the oral form of disease. Nineteen (51%) dogs were treated with other chemotherapeutic agents before receiving CCNU. All dogs had detectable disease at the time CCNU therapy was initiated. Dogs received a median starting CCNU dosage of 70 mg/m2 (range, 50-100 mg/m2). The median number of treatments administered was 3 (range, 1-12 treatments). After the initial treatment, the CCNU dosage was adjusted in 9 of 26 (35%) dogs in which CCNU was continued: 7 had dosage reductions, and 2 had dosage escalations. Twenty-eight of 36 (78%) dogs had a measurable response to CCNU for a median duration of 106 days (95% confidence interval [CI], 75-182). Six dogs (17%) had a complete response, including 5 dogs with the cutaneous form and 1 dog with the oral form. Twenty-two dogs (61%) had a partial response, including 20 dogs with the cutaneous form and 2 dogs with the oral form, for a median duration of 88 days (95% CI, 62-170). Toxicoses after CCNU chemotherapy included myelosuppression in up to 29% of the dogs, gastrointestinal signs in up to 22% of the dogs, and liver enzyme activity increases in up to 86% of the dogs. This study demonstrates that CCNU chemotherapy can be considered a reasonable option for the treatment of canine epitheliotropic lymphoma in dogs.     

Chronic tracheobronchial syndrome in eight dogs.

Chronic tracheobronchial syndrome was diagnosed in eight dogs which had had a chronic mild cough for two to 13 months but were otherwise clinically normal. In five of them there was evidence of contact with other coughing dogs before the appearance of clinical signs and the majority at first responded favourably to antibacterial therapy. The coughing occurred mainly when the dogs pulled on their leads or became excited. Three cases had bronchoscopic evidence of active airway inflammation, and five had varying numbers of inflammatory cells (neutrophils) in bronchial aspirates. There was no evidence of excessive production of mucus in the airways of any of the dogs. Seven had an increased bronchial pattern on radiographs but only one of the dogs has developed chronic bronchitis.     

Tolerance of cutaneous or mucosal flaps placed into a radiation therapy field in dogs

OBJECTIVE: To determine the clinical outcome and factors affecting cutaneous or mucosal flaps in dogs treated with radiation therapy (RT). STUDY DESIGN: Longitudinal clinical study. ANIMALS: Twenty-six client-owned dogs. METHODS: Dogs entered in the study had a flapping procedure and RT as part of their treatment. The sequence of flapping and RT included: (1) planned preoperative RT, (2) postoperative RT, and (3) flapping as a salvage procedure for management of complications or local tumor recurrence after RT. Flap complications were defined as necrosis, local infection, dehiscence, and ulceration. The risk and severity of flap complication were analyzed independently. RESULTS: Twenty (77%) dogs had a complication; 6 dogs required an additional flapping procedure; and 4 dogs had an unresolved complication. Flapping procedures performed to correct a complication, or failure of RT, had a significantly greater risk for complication; however, postoperative RT decreased the severity of complication. A dose per fraction of 4 Gy compared with 3 Gy was prognostic for increased severity of complications, whereas the head and neck location was prognostic for decreased severity of complication. CONCLUSIONS: Although morbidity was substantial, cutaneous or mucosal flaps were used successfully in an RT field in 85% of the dogs. Flaps that were part of the planned therapy as opposed to those used to correct a complication or failure of RT had a better clinical outcome. CLINICAL RELEVANCE: Cutaneous or mucosal flaps can be part of the treatment of dogs with tumor when adjuvant or neoadjuvant RT is to be used.     

Subepidermal linear alignment of mast cells in inflammatory dermatoses of the dog

A recent study demonstrated that 47.7% of dogs with Malassezia dermatitis had a subepidermal linear alignment of mast cells (SLAM). A retrospective histopathological study was conducted on 419 canine skin biopsies to determine if a SLAM was present in other inflammatory diseases. Cases examined included dogs with demodicosis, sarcoptic mange, dermatophytosis, pemphigus foliaceus, pemphigus erythematosus, discoid lupus erythematosus, systemic lupus erythematosus, erythema multiforme, dermatomyositis, staphylococcal pyoderma, primary seborrhea, arthropod bites, contact hypersensitivity, flea bite hypersensitivity, atopy, and food hypersensitivity. Three cases (3/419, 0.7%) were identified with SLAM. The diagnoses for these cases were atopy (1/23, 4%) with a secondary bacterial folliculitis (1/136, 0.7%), pemphigus erythematosus (1/18, 6%), and discoid lupus erythematosus (1/16, 6%). Based on this study, SLAM is significantly more common in Malassezia dermatitis than in other inflammatory diseases.     

Cutaneous reactive histiocytosis in dogs: a retrospective evaluation of 32 cases

Thirty-two cases of canine cutaneous histiocytosis were retrospectively evaluated. Median age at onset was 4 years. Lesions included nodules and plaques affecting the head/face, trunk and limbs, and erythema, swelling and depigmentation of the nasal planum/nares. Systemic involvement was not ruled out in all cases. All dogs had complete resolution of dermatological lesions after initial treatment (median 45 days). Initial treatment included prednisone +/- antibiotics (12 of 32 dogs), prednisone and tetracycline/niacinamide (four of 32), prednisone and azathioprine (three of 32), tetracycline/niacinamide +/- vitamin E/essential fatty acids (six of 32), antibiotics +/- antihistamines (three of 32), cyclosporine and ketoconazole (one of 32), topical therapy (two of 32), and no treatment (one of 32). Seventeen dogs received maintenance therapy which consisted of tetracycline/niacinamide +/- vitamin E/essential fatty acids (12 of 17), cyclosporine/ketoconazole (two to three times a week) (two of 17), azathioprine daily (one of 17), prednisone/azathioprine (two times a week) (one of 17), and prednisone daily (one of 17). Median follow up was 25 months. Nine dogs had a recurrence of cutaneous histiocytosis (median days to recurrence 130 days), with seven of nine having more than one recurrence. At study completion, six dogs were deceased (no lesions at the time of death) and 26 of 32 were alive with no lesions. Ten of 26 dogs were on maintenance treatment (eight tetracycline/niacinamide, one azathioprine, one vitamin E). Previous dermatological disease and season had no detectable influence on recurrence. Recurrence was significantly more likely in dogs with nasal planum/nares lesions than dogs without these lesions. Tetracycline/niacinamide was an effective treatment option for dogs in this study population.     

Long-term management of atopic disease in the dog

Canine atopy is a common dermatologic disorder. Because the disease most frequently strikes young dogs, lifetime management strategies are necessary. Consideration must be given to the treatment of pruritus and secondary manifestations of the allergy, such as pyoderma, otitis externa, and seborrhea, to manage these patients successfully. The use of glucocorticoid therapy and hyposensitization are discussed.     

Abnormal cutaneous response to mitogens and a contact allergen in dogs with atopic dermatitis

Antigen specific and nonspecific T-lymphocyte activity was evaluated in normal dogs and in dogs with atopic dermatitis by measuring the increase in skin thickness after application of the contact allergen dinitrochlorobenzene and after intradermal injection of the mitogens phytohemagglutinin and concanavalin A. The atopic dogs had a significantly reduced response to the contact allergen (P less than or equal to 0.001) but a significantly increased response to the mitogens (P less than or equal to 0.001). The atopic and normal dogs responded similarly to intradermally injected histamine. The response of dogs with non-atopic skin conditions to the cutaneous mitogen test was like that of normal dogs. Pre-existing dermatitis does not apparently influence cutaneous response to mitogens in dogs. The cutaneous response of atopics during treatment with corticosteroids is not different from normal controls. These results suggest a role for altered cell-mediated immunity in the pathogenesis of canine atopy and that the cutaneous mitogen test may have value as a rapid screening test for the disease.     

Bilateral Ureteroileostomy and Perineal Urinary Diversion in Dogs

The urinary bladder was excised, and the ureters were implanted into an isolated segment of distal jejunum and ileum in three experimental dogs. The isolated bowel loop was drawn through the pelvic canal within the external anal sphincter to exit ventral to the anus. The dogs were evaluated for urinary continence, urinary tract infection, and renal function for up to 6 months postoperatively.
Urinary continence did not return. Continuous urine leakage caused perineal scalding. The cutaneous openings of the isolated bowel loops developed strictures. Serum creatinine and urea nitrogen concentrations did not increase. Excretory urography and retrograde radiographic studies of the bowel loop were performed periodically. Unilateral hydronephrosis was observed in two dogs 2 weeks postoperatively. The remainder of the excretory urograms were normal. Ureteral reflux was observed commonly on retrograde contrast studies. Positive bacterial cultures were obtained from all bowel loops and kidneys at necropsy. Alpha-streptococcus, Escherichia coli , and Proteus spp. were isolated most frequently. Mild pyelitis was seen in histopathologic examination of the kidneys after necropsy. Urothelium replaced bowel mucosa near the site of ureteral implantation.
This method of urinary diversion is not satisfactory for clinical use.     

Evaluation of prognostic indicators in dogs with multiple,simultaneously occurring cutaneous mast cell tumours: 63 cases

Sixty‐three dogs with multiple contemporaneous cutaneous mast cell tumours (MCTs) were identified. The aim of this study was to determine the significance of breed, concurrent dermatological condition; number of cutaneous MCTs, size, location, histological grade and mitotic index; completeness of excision (complete, close or incomplete); local recurrence, metastasis and adjuvant therapy for the prognostic evaluation of dogs with a unique disease presentation of multiple, simultaneously occurring cutaneous MCTs. On the basis of multivariable survival analysis, dogs with one recorded grade 3 MCT had shorter progression‐free survival (PFS) times (18.7 versus 2.2 months) and median survival times (MSTs) (24 versus 3 months). Dogs treated with adjuvant vinblastine/lomustine had a 16 times increased risk of dying. MSTs were found to be significantly longer in dogs with one recorded MCT on an extremity. For all dogs, the PFS (range 14–1835 days) and MSTs (range 28–1835 days) were not reached.     

Deionised water as an adjunct to surgery for the treatment of canine cutaneous mast cell tumours

Medical records of 55 dogs with a diagnosis of cutaneous mast cell tumour were reviewed. Twenty-seven of the dogs were treated with surgery plus deionised water and the remaining 28 with surgery alone. A survival analysis was performed to determine whether deionised water, as an adjunct to surgery for cutaneous mast cell tumour, affected survival time or time to tumour recurrence. Dogs in which mast cell tumour recurred had a significantly shorter survival time compared with dogs with no recurrence (P=0.05), regardless of the method of treatment. A significant negative association between tumour recurrence and method of treatment (P=0.0097) and clinical stage (P=0.0223) was observed. Dogs treated with surgery and deionised water had a significantly shorter time to recurrence of their mast cell tumour (P=0.0113). Based on these results, deionised water does not appear to be beneficial in prolonging survival time or time to tumour recurrence for dogs with cutaneous mast cell tumours.     

Abdominal CT evaluation of the liver and spleen for staging mast cell tumors in dogs yields nonspecific results

Canine mast cell tumor staging is commonly performed using abdominal ultrasonography and fine‐needle aspiration cytology of masses, lymph nodes, and hepatic and splenic parenchyma. Computed tomography is used for abdominal, thoracic, or whole body imaging in staging mast cell tumors in the authors’ institution enabling evaluation of multiple body areas in one examination. The aim of this study was to compare the CT examinations acquired for staging of mast cell disease to their subsequent liver and spleen cytology findings. Medical records of dogs with primary mast cell tumors that underwent abdominal CT and concurrent liver and spleen aspirates were reviewed. The CT examinations were evaluated for attenuation, size, and margination of the liver and spleen. The relationship between CT findings and cytology results was analyzed. Forty‐nine dogs matched the inclusion criteria: five of forty‐nine dogs with cutaneous mast cell tumors were positive for metastasis from liver and/or spleen aspirates. Of the five dogs with cytological evidence of liver or spleen metastasis, four had normal CT liver attenuation and size, one dog had concurrent primary hepatocellular neoplasia, four dogs had abnormal splenic parenchyma (two nodular and two diffuse heterogeneity), and one dog had a normal attenuation of the spleen. In four dogs, the spleen was subjectively enlarged. Computed tomographic evaluation of the liver showed no consistent pattern associated with mast cell metastasis and did not predict cytology results. Multifocal splenic hypoattenuating lesions more commonly coincided with mast cell metastasis. Sampling of the liver and spleen remains to be considered in the absence of abnormal CT findings for full staging.     

Infrequent detection of papillomaviral DNA within canine cutaneous squamous cell carcinomas, haemangiosarcomas and healthy skin on the ventrum of dogs

Background – Canine squamous cell carcinomas (SCCs) most frequently develop on the ventral abdomen and are thought to be caused by ultraviolet (UV) light. Papillomaviruses (PVs) have been associated with cutaneous SCCs in multiple species, including dogs. Hypothesis – That PVs act as cofactors in canine UV‐induced SCCs. Animals – The study was performed on skin from the ventrum of 60 dogs. These samples included 20 SCCs, 20 haemangiosarcomas and 20 samples of clinically normal skin. Two canine viral plaques were included as positive controls for PV. Methods – PCR was used to amplify PV DNA from all samples. Primers used included two sets of consensus primers and two sets of primers that were designed specifically to amplify PV DNA sequences detected in the viral plaques. Results – The MY09/11 consensus primers amplified PV DNA from both viral plaques. One plaque contained a DNA sequence (CfPV‐JM) that had been previously reported from a dog with multiple cutaneous SCCs. The other plaque contained a previously unreported PV DNA sequence. No PV DNA was amplified by either consensus primer from any of the ventrum skin samples. Primers designed specifically to amplify the CfPV‐JM sequence amplified DNA from one SCC, but no other sample. No PV DNA was amplified using the other specific PCR primer set. Conclusions and clinical importance – These results do not support a significant role for PVs in SCC development from the ventrum of dogs. However, they contribute another PV sequence to the list of PVs that have been associated with viral plaque development in dogs.     

Use of high-frequency ultrasonography for evaluation of skin thickness in relation to hydration status and fluid distribution at various cutaneous sites in dogs

OBJECTIVE: To assess the usefulness of high-frequency diagnostic ultrasonography for evaluation of changes of skin thickness in relation to hydration status and fluid distribution at various cutaneous sites in dogs. ANIMALS: 10 clinically normal adult dogs (6 males and 4 females) of various breeds. PROCEDURES: Ultrasonographic examination of the skin was performed before and after hydration via IV administration of an isotonic crystalloid solution (30 mL/kg/h for 30 minutes). A 13-MHz linear-array transducer was used to obtain series of ultrasonographic images at 4 different cutaneous sites (the frontal, sacral, flank, and metatarsal regions). Weight and various clinicopathologic variables (PCV; serum osmolality; and serum total protein, albumin, and sodium concentrations) were determined before and after the infusion. These variables and ultrasonographic measurements of skin thickness before and after hydration were compared. RESULTS: Among the 10 dogs, mean preinfusion skin thickness ranged from 2,211 microm (metatarsal region) to 3,249 microm (sacral region). Compared with preinfusion values, weight was significantly increased, whereas PCV; serum osmolality; and serum total protein, albumin, and sodium concentrations were significantly decreased after infusion. After infusion, dermal echogenicity decreased and skin thickness increased significantly by 21%, 14%, 15%, and 13% in the frontal, sacral, flank, and metatarsal regions, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Cutaneous site and hydration were correlated with cutaneous characteristics and skin thickness determined by use of high-frequency ultrasonography in dogs. Thus, diagnostic ultrasonography may be a useful tool for the noninvasive evaluation of skin hydration in healthy dogs and in dogs with skin edema.