Canine acute radiation dermatitis, a survey of current management practices in North America

Acute radiation‐induced dermatitis (ARID) is a common sequela of radiation therapy in dogs. There is no consensus regarding ARID management in human medicine and the standard of care in veterinary medicine has not been reported. The objective was to report the practice standards for ARID management in dogs in North America. The design used was a questionnaire survey. Fifty‐eight private and university teaching veterinary hospitals were contacted, 54 participated. The topical and oral medications used to treat ARID, prevent or treat bacterial infection, control pain and the indications for and timing of treatment initiation were the outcome measures. A minority of facilities (4/54, 7.5%) use exactly the same protocol regarding all parameters. There was agreement (>75% of facilities) with respect to the general use of oral antibiotics (77.8%), the need for pain control (92.6%) and the use of tramadol for pain control (76%), although the details of their use varied widely. There is a divergence of opinions regarding all details of ARID management in dogs except the general use of oral antibiotics and pain control medications.     

Investigation on the clinical efficacy and safety of 0.1% tacrolimus ointment (Protopic) in canine atopic dermatitis: a randomized, double-blinded, placebo-controlled, cross-over study

Topical tacrolimus is successfully used in people with atopic dermatitis. Preliminary studies in dogs with atopic dermatitis using tacrolimus in a compounded lotion formulation indicated that tacrolimus significantly decreased erythema and pruritus according to investigator, but no significant improvement was reported by the dog owners. The objectives of this study were to evaluate the clinical efficacy and safety of the commercially available 0.1% tacrolimus ointment (Protopic) in dogs with atopic dermatitis. The study was designed as a double-blinded, placebo-controlled, cross-over study. Selected dogs were allocated to either tacrolimus or placebo for 4 weeks. After 4 weeks there was a wash-out period of 2 weeks and treatments were switched. Twelve dogs completed the study. Clinical signs were scored. Blood samples were collected for complete blood count, chemistry panels and tacrolimus levels at week 0 and 4 of each treatment. Tacrolimus ointment significantly decreased severity of symptoms for both owners and investigators at the end of the trial. When the same dogs received the placebo, there were no differences between week 0 and week 4 scores. Dogs with localized disease responded better than dogs with generalized disease. Tacrolimus was detected in the blood of animals receiving the active ingredient. Levels were below the level of toxicity and no adverse effects were reported in any of the dogs. No changes in complete blood count and chemistry parameters were detected between groups or within groups. In conclusion, tacrolimus appears to be a safe alternative treatment in dogs with atopic dermatitis, especially in those with localized disease.     

Identification of major allergens of Malassezia pachydermatis in dogs with atopic dermatitis and Malassezia overgrowth

Abstract We have previously shown that both atopic and normal dogs generate an IgG response to antigens of Malassezia pachydermatis . The aim of this study was to compare IgE responses to separated proteins of M. pachydermatis in 28 atopic dogs with Malassezia dermatitis and 22 clinically normal dogs using Western immunoblotting. Six different detection systems were evaluated in order to assess sensitivity and eliminate nonspecific binding and cross-reactivity. The protocol yielding the best results utilized a monoclonal mouse antidog IgE, an alkaline phosphatase conjugated goat antimouse IgG which had been passed through a canine IgG column 3 times, a chemiluminescent substrate and a digital imaging system. Proteins of 45, 52, 56 and 63 kDa were recognized by more than 50% of the atopic dog sera and thus represented major allergens. Only a minority of normal dogs showed faint IgE binding to these proteins. The results indicate that the majority of atopic dogs with Malassezia dermatitis have a greater IgE response than normal dogs, suggesting an IgE-mediated immune response may be clinically important in the pathogenesis of the disease.     

The effects of capsaicin topical therapy in dogs with atopic dermatitis: a randomized,double-blinded,placebo-controlled,cross-over clinical trial

Abstract The efficacy of twice daily topical application of capsaicin (0.025%) for the management of pruritus in dogs with atopic dermatitis (AD) was evaluated in double-blinded, placebo-controlled study. Twelve dogs with AD were randomly assigned to either 0.025% capsaicin or vehicle lotion applied twice daily for 6 weeks. After a 4-week wash-out period, treatments were switched. Significant improvement was reported by owners ( P  = 0.0006), but not by investigators. Owners noted temporary worsening of pruritus after the first week of capsaicin therapy. Overall capsaicin was well tolerated. Substance P (SP) concentrations in the skin did not correlate with the severity of the pruritus and did not change significantly over time and between treatments. Lesional skin had less SP than nonlesional skin ( P  = 0.03). These observations suggest that topical capsaicin should be further evaluated as an adjunctive antipruritic agent in dogs with AD.     

Therapeutic efficacy of topical hydrocortisone aceponate in experimental flea-allergy dermatitis in dogs

Objective   To evaluate the treatment efficacy of a topical spray containing hydrocortisone aceponate (HCA) on dogs with flea-allergy dermatitis (FAD).
Design   A controlled clinical study was conducted on dogs with experimentally induced FAD. Sixteen laboratory beagles with mild to moderate clinical signs were divided into two groups. The test group received HCA by topical spray once daily for 7 days, while the control group did not. Pruritic events (time and frequency) were videotaped and then scored. Clinical signs (erythema, papules, excoriation and alopecia) present on four anatomical regions were monitored and their severity directly assessed.
Results   After 2 days, pruritus was reduced by 94% in the treatment group and by 24% in the control group (P = 0.014) in cumulative time, and by 86% versus 34% (P = 0.034) in frequency. The HCA spray also resulted in significant improvements in overall clinical signs: 23% versus 0% in the control group (P = 0.0006) on day 3 and 43% versus 15% in the control group (P = 0.0006) on day 7. During the 7-day trial, no drug-related adverse effects were observed.
Conclusions   Topical treatment with HCA showed a rapid and potent antipruritic effect on dogs with FAD. HCA also demonstrated significant overall therapeutic effects on FAD-associated skin lesions.     

Aero-allergens in canine atopic dermatitis in southeastern Australia based on 1000 intradermal skin tests

OBJECTIVE: To determine the most relevant aero-allergens involved in canine atopic dermatitis in southeastern Australia and provide information about these aero-allergens to the general practitioner. PROCEDURE: Dogs presented to the Animal Skin & Allergy Clinic with history and clinical signs of atopic dermatitis were injected intradermally with 38 different allergens and negative and positive control. Intradermal skin tests in 1000 dogs were retrospectively evaluated. RESULTS: One third of all patients reacted to the house dust mite Dermatophagoides farinae. Allergens reacting in more than 15% of the patients were wheat (Triticum aestivum), sweet vernal (Anthoxanthum odoratum), English couch (Agropyron repens), yellow dock (Rumex crispus), Mexican tea (Chenopodium ambrosioides), plantain (Plantago lanceolata), melaleuca (Melaleuca quinquenervia) and peppercorn (Schimus spp). CONCLUSION: House dust mites are the most common allergens in canine atopic dermatitis in southeastern Australia and D farinae is involved most frequently. However, a number of grass, weed and tree pollens also are involved regularly.     

Disseminated nocardiosis caused by Nocardia abscessus in a dog

Abstract: A 4‐year‐old female spayed Bichon Frise dog that had been receiving cyclosporine A per os 3 times per week for 2 months to control allergic dermatitis developed lethargy, anorexia, fever, and multiple firm subcutaneous masses. Pyogranulomatous inflammation with branching nonseptate filamentous organisms approximately 2 μm in diameter, presumptively fungal organisms, was diagnosed by cytologic evaluation of fine‐needle aspirates from several masses. A partially acid‐fast actinomycete was cultured from 2 of the masses. The organism was identified as Nocardia abscessus (formerly Nocardia asteroides type 1) based on 16S ribosomal DNA sequencing of samples extracted from cultures and unstained cytologic smears. Immunosuppression caused by long‐term administration of cyclosporine A likely predisposed the dog to disseminated infection. To our knowledge, this is the first report of N. abscessus infection in a dog. This case demonstrates that N. abscessus may be mistaken for a fungal organism based on its cytologic appearance and underscores the importance of using molecular techniques for the diagnosis of suspected fungal diseases.     

Sensitization rates of causative allergens for dogs with atopic dermatitis: detection of canine allergen-specific IgE

Allergen-specific IgE serology tests became commercially available in the 1980s. Since then these tests have been widely used to diagnose and treat allergic skin diseases. However, the relationship between a positive reaction and disease occurrence has been controversial. The purpose of this study was to evaluate allergens using a serologic allergy test in dogs with atopic dermatitis (AD). Dogs clinically diagnosed with AD (n=101) were tested using an allergen-specific IgE immunoassay. Among the total 92 environmental and food allergens, house dust and house dust mites were the most common. Several allergens including airborne pollens and molds produced positive reactions, and which was considered increasing allergens relating to the climate changes. The presence of antibodies against staphylococci and Malassezia in cases of canine AD was warranted in this study. Additionally, strong (chicken, turkey, brown rice, brewer''s yeast, and soybean) and weakly (rabbit, vension, duck, and tuna) positive reactions to food allergens could be used for avoidance and limited-allergen trials.     

Tertiary hypothyroidism in a dog

: A nine-year-old male entire Labrador was diagnosed with pituitary dependent hyperadrenocorticism. Following seven months of successful mitotane therapy, the dog presented with marked weight gain, seborrhoea and alopecia. Routine clinicopathological analyses revealed marked hypercholesterolaemia. Serum total and free thyroxine (T4) concentrations were below their respective reference ranges. Serum thyroid stimulating hormone (cTSH) concentration was within reference range. TSH and thyrotropin releasing hormone (TRH) response tests revealed adequate stimulation of total T4 in both, and cTSH in the latter test. Magnetic resonance imaging revealed a mass arising from the pituitary fossa, with suprasellar extension. A diagnosis of tertiary hypothyroidism was made. Following four weeks of levothyroxine therapy, circulating cholesterol concentration had declined, weight loss had ensued and dermatological abnormalities had improved. Euthanasia was performed four months later due to the development of neurological signs. A highly infiltrative pituitary adenoma, with effacement of the overlying hypothalamus was identified on post mortem examination. Tertiary hypothyroidism has not been previously reported in dogs.     

The antimicrobial susceptibility of Staphylococcus species isolated from canine dermatitis

In a retrospective study, 1538 strains of -haemolysin-producing Staphylococcus species isolated from dermatitis in dogs at three veterinary clinical microbiology laboratories in Norway during 1986–87 and 1993–94 were investigated for their antimicrobial susceptibility. None of the strains was resistant to cloxacillin, cephalexin or the quinolones enrofloxacin and ciprofloxacin. More than 96% of the strains were susceptible to trimethoprim-sulphonamide, bacitracin and fucidic acid. Between 67% and 89% of the strains were susceptible to erythromycin, lincosamides, tetracycline, neomycin and chloramphenicol. Only 37.9% of the strains were susceptible to penicillin. The frequency of penicillin resistance increased significantly between the first and second periods, from 46.0% to 58.6%. The frequency of resistance to lincomycin, clindamycin and erythromycin also increased significantly between the first and second periods, from 3.0%, 2.1% and 3.3% to 25.5%, 19.5% and 24.8%, respectively. A moderate increase in resistance to tetracycline was also noted, from 20.4% in the first to 27.6% in the second period. On the other hand, the frequency of resistance to trimethoprim-sulphonamide decreased significantly from 4.1% in the first to 0.9% in the second period. Many different resistance patterns were observed in each period. However, the proportion of multiresistant strains increased from 2.1% in the first to 10.2% in the second period. There was a decrease in resistance to the combination of trimethoprim-sulphonamide and penicillin from the first to the second period. Resistance to the combination of lincosamides and pencillin increased. For the combinations penicillin-tetracycline-lincosamides, pencillin-lincosamides-erythromycin, and pencillin-tetracycline-lincosamides-erythromycin, there was a striking increase in resistance between the first and the second periods.Abbreviations CVL Central Veterinary Laboratory - NCVM Norwegian College of Veterinary Medicine - NVL Norwegian Veterinary Laboratory     

Surgical removal of a localised vascular hepatic hamartoma in a dog

A 2-year-old male Labrador Retriever was presented for sudden abdominal distension. Abdominal ultrasonography revealed abundant abdominal fluid and a hepatic mass, which was removed by total lobectomy. Histologic evaluation of the mass supported a vascular hepatic hamartoma. Vascular hamartomas are rare malformations in animals and only two cases have been reported in the dog. This is the first recorded case of a canine vascular hepatic hamartoma treated surgically and having a successful long-term outcome.     

Omentalisation of a caudal mediastinal abscess in a dog

A caudal mediastinal abscess was diagnosed in a 2-year-old German Short-haired Pointer with acute onset of lethargy, pyrexia and tachypnoea. The abscess was managed surgically by median sternotomy, abscess content evacuation and omentalisation of the abscess cavity via the diaphragm. Although surgical management of mediastinal abscesses has been reported previously, this is the first report to describe successful management of the condition in a dog by omentalisation.     

Malassezia dermatitis in the dog: a retrospective histopathological and immunopathological study of 86 cases (1990–95)

A retrospective histopathological and immunopathological study was conducted on 86 dogs with Malassezia dermatitis. West Highland White terriers, English Setters, Shih Tzus, Basset Hounds, American Cocker Spaniels, spayed females, and castrated males were found to be at increased risk. The histopathological reaction pattern of lymphocytic superficial perivascular to interstitial dermatitis with parakeratotic hyperkeratosis, irregular epidermal hyperplasia, diffuse intercellular oedema and lymphocytic exocytosis was found to be consistent with a diagnosis of Malassezia dermatitis whether yeast were histologically visible (73.3% of the cases) or not (26.7%). Immunopathological studies revealed that 60– > 90% of the inflammatory cells within the epidermis, and 25–75% of those within the dermis were CD3+T lymphocytes, and that the only immunoglobulin-positive cells were dermal plasma cells.     

Emphysematous cystitis in a chemically-induced diabetic dog

Emphysematous cystitis is a rare disorder caused by bacterial infection and characterized by gas accumulation within the bladder wall with cyst formation. This report describes the histopathological characteristics of emphysematous cystitis found in a diabetic female beagle induced by streptozotocin and alloxan. Macroscopically, multiple cyst-like structures were observed on the cut surface of the urinary mucosa. During fixation, small specimens cut from the mucosa floated on the surface of the fixative solution. Histopathologically, multiple cysts were lined with a single layer of flattened cells found to be immunohistochemically positive for vimentin, partially positive for α-smooth muscle actin or macrophage scavenger receptor, class A, and thought to be myofibroblasts, fibroblasts or macrophages. Multinucleated giant cells were observed around the cysts, and gram-negative short bacilli were observed in the lumen of the urinary bladder. From these findings, this case was diagnosed as emphysematous cystitis.