Suspected contact scrotal dermatitis in the dog: a retrospective study of 13 cases (1987 to 2003)

Objectives : The aim of this study was to assess the clinical and aetiological aspects of contact dermatitis of the scrotum in dogs. Methods : The medical records of 13 dogs with suspected scrotal contact dermatitis were retrospectively included in the study. For each case, historical findings, results of physical and dermatological examination and of avoidance tests as well as follow‐up were included. Results of re‐exposure tests and patch tests were also included when available. Results : Avoidance tests to various suspected substances such as floor detergents, bleach, cement, laundry detergent and plastic fabric were performed and led to clinical improvement in all patients. Provocative re‐exposure was performed in six cases, with five positive responses. Patch tests were undertaken in three of the five re‐exposed cases, with two responding positively. Clinical Significance : Scrotal skin is thin and with few hair follicles, and is therefore very susceptible to contact dermatitis. A range of substances can induce contact dermatitis. The diagnosis of contact dermatitis is made by results of avoidance and/or provocation tests and/or patch tests. Once an aetiological agent has been identified, treatment is straightforward consisting of avoidance of this agent.     

Pilot evaluation of the efficacy of shampoo treatment with ultrapure soft water for canine pruritus

Ultrapure soft water (UPSW) is water in which calcium and magnesium ions have been replaced with sodium ions using a cation‐exchange resin. We recently demonstrated that washing with soap and UPSW reduced the clinical severity of dermatitis and improved the skin barrier function in NC/NgaTnd mice, a murine model for human atopic dermatitis. The purpose of this pilot study was to evaluate the efficacy of shampoo treatment with UPSW for dogs with pruritus. Eleven dogs with pruritus were randomly assigned to two groups depending on whether they received weekly shampoo treatment with UPSW or tap water for 4 weeks. After a washout period, the treatment protocol was switched such that each dog received both treatments. The pre‐treatment and post‐treatment values of the following were compared: pruritus scores assessed by the owners; dermatitis scores recorded by an investigator; and transepidermal water loss (TEWL). Shampoo treatment with UPSW significantly decreased pruritus and dermatitis scores in the dogs, whereas shampoo treatment with tap water did not. In addition, shampoo treatment with UPSW, but not with tap water, significantly reduced TEWL in the dogs. Adverse events due to the treatment were not observed in the dogs. Furthermore, we found that topical application of UPSW for barrier‐disrupted skin caused by tape stripping in healthy dogs decreased TEWL more rapidly than topical application of tap water. Our findings suggest that shampoo treatment with UPSW promotes skin barrier recovery and thus could be considered as a possible therapeutic option in the management of pruritus and dermatitis in dogs.     

Systemic lupus erythematosus in a cat: fulfillment of the American Rheumatism Association criteria with supportive skin histopathology

Systemic lupus erythematosus (SLE) was diagnosed in a 9-year-old castrated male Persian cat. The cat described is the first to fulfil four of 11 American Rheumatism Association criteria for the diagnosis of SLE in humans (symmetrical facial dermatitis, thrombocytopenia, positive antinuclear antibodies, oral ulceration) with supportive skin histopathology. Haematological abnormalities included a mild anaemia and severe thrombocytopenia. Skin disease consisted of symmetrical multifocal alopecia with crusting, predominantly on the face. Histopathology of the skin revealed interface dermatitis and interface folliculitis with follicular atrophy. Complete remission was obtained with corticosteroid therapy.     

Patch test reactions to house dust mites in dogs with atopic dermatitis

The purpose of this study was to determine the percentage of dogs with spontaneous atopic dermatitis that show a positive patch test reaction to a commercially available 20% house dust mites mixture containing equal parts of Dermatophagoides farinae and Dermatophagoides pteronyssinus in white petrolatum. In addition, we evaluated whether skin reactions induced after the epicutaneous application of house dust mites were clinically and histologically similar to naturally developed skin lesions of dogs with atopic dermatitis. Furthermore, we investigated if the reactions induced by house dust mites were true allergic reactions by comparing them to atopic lesional skin and to patch test reactions induced by an irritant substance (sodium lauryl sulphate). White petrolatum alone and nonlesional skin sites were used as negative controls. Macroscopic and microscopic evaluations of the patch test and control sites were performed in a blinded fashion at 48 and 72 h after patch test application. Microscopic results were evaluated in a qualitative and quantitative manner. A chi‐square test for homogenicity was used for the quantitative analysis to compare the proportion of each dermal inflammatory cell type among positive histopathological tested sites. P values ≤ 0.05 were considered significant. The study included 12 healthy nonatopic dogs and 13 dogs with nonseasonal atopic dermatitis. None of the nonatopic dogs reacted to house dust mites and white petrolatum. Ten (77%) of the 13 atopic dogs reacted macroscopically and histopathologically to house dust mites. Macroscopic reactions induced by house dust mites were characterized by erythema, oedema and papules. The macroscopic reactions induced by house dust mites were identical to lesional skin in 20% of the dogs and identical to reactions induced by sodium lauryl sulphate in 40% of the dogs. Qualitative histopathological findings showed that the reactions induced by house dust mites were similar to atopic lesional skin in 80% of the dogs and were similar to sodium lauryl sulphate in 20% of the dogs. Quantitative analyses showed that the proportion of neutrophils in reactions induced by sodium lauryl sulphate was significantly higher (P < 0.05) compared to house dust mites reactions, which could be a differentiator factor between an allergic and an irritant reaction. These results showed that the epicutaneous application of house dust mites in dogs with atopic dermatitis induced histopathological lesions similar to spontaneous atopic lesions in dogs. Therefore, this study demonstrated that house dust mites penetrated the skin of dogs with atopic dermatitis and induced an inflammatory response that resembled a true allergic reaction. Funding: Small Companion Animal Grant, University of Minnesota.     

A case of superficial suppurative necrolytic dermatitis of miniature schnauzers with identification of a causative agent using patch testing

A 9‐year‐old, castrated male, miniature schnauzer presented with malaise, anorexia, fever and severe inflammatory skin lesions on the dorsum, thighs and pinnae. The lesions developed 2 days after bathing with a commercial shampoo. Histopathological examination of skin samples revealed neutrophilic exocytosis, parakeratosis, epidermal hyperplasia and neutrophilic infiltration in the superficial dermis. Skin lesions resolved completely after 14 days of treatment with prednisolone and ofloxacin. Patch testing performed on the patient and a clinically healthy dog showed erythema at the site exposed to the culprit shampoo 48 h later only on the patient. Histopathological findings of the erythematous reaction were similar to those of the spontaneous skin lesions. Based on these findings, the dog was diagnosed with superficial suppurative necrolytic dermatitis of miniature schnauzers. The patch test results suggested that contact dermatitis to a commercial shampoo played a role in the pathogenesis of this disease.     

Combined moxidectin and environmental therapy do not eliminate Chorioptes bovis infestation in heavily feathered horses

Chorioptes bovis infestation is a common cause of pastern dermatitis in the horse, with a predilection in draft horses and other horses with thick hair ‘feathers’ on the distal limbs. The treatment of this superficial mite is challenging; treatment failure and relapse are common. Furthermore, C. bovis infestation may affect the progression of chronic pastern dermatitis (also known as chronic proliferative pastern dermatitis, chronic progressive lymphoedema and dermatitis verrucosa) in draft horses, manifesting with oedema, lichenification and excessive skin folds that can progress to verruciform lesions. An effective cure for C. bovis infestation would therefore be of great clinical value. In a prospective, double‐blind, placebo‐controlled study, the efficacy of oral moxidectin (0.4 mg/kg body weight) given twice with a 3 week interval in combination with environmental treatment with 4‐chloro‐3‐methylphenol and propoxur was tested in 19 heavily feathered horses with clinical pastern dermatitis and C. bovis infestation. Follow‐up examinations over a period of 180 days revealed significantly more skin crusting in the placebo group than in the treatment group. However, no other differences in clinical signs or the numbers of mites detected were found between the two groups. The results of this study suggest that moxidectin in combination with environmental insecticide treatment as used in this study is ineffective in the treatment of C. bovis in feathered horses.     

Detection of feline herpesvirus 1 DNA in skin biopsy specimens from cats with or without dermatitis

OBJECTIVE: To compare detection rates of feline herpesvirus 1 (FHV-1) DNA in skin biopsy specimens from cats with herpetic dermatitis, cats with nonherpetic dermatitis, and cats without dermatitis. DESIGN: Prevalence survey. Animals-5 cats (9 biopsy specimens) with herpetic ulcerative dermatitis, 14 cats (17 biopsy specimens) with nonherpetic ulcerative dermatitis, and 8 cats (21 biopsy specimens) without clinically apparent skin lesions. PROCEDURES: A single-phase PCR assay was used to detect FHV-1 DNA in biopsy specimens. Assay results were compared with results of histologic examination. RESULTS: FHV-1 DNA was detected in all 9 biopsy specimens from the 5 cats with herpetic dermatitis and in 1 of 17 biopsy specimens from the 14 cats with nonherpetic dermatitis, but was not detected in any of the 21 biopsy specimens from the 8 cats without dermatitis. When results of histologic examination were used as the gold standard, sensitivity and specificity of the PCR assay were 100% and 95%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Results confirmed that FHV-1 DNA can be detected in the skin of cats with herpetic dermatitis and suggest that the virus may play a causative role in the disease. In addition, the PCR assay may be useful in confirming a diagnosis of herpetic dermatitis.     

Ciclosporin therapy is associated with minimal changes in calcium metabolism in dogs with atopic dermatitis

Background – Ciclosporin is widely used in the management of canine atopic dermatitis. In humans, ciclosporin therapy has been linked to disturbances in calcium metabolism and resultant skeletal disorders. Objectives – The objective of this study was to assess calcium homeostasis in dogs before and after a 6 week course of once daily oral ciclosporin at the licensed dose (5 mg/kg). Animals – Sixteen client‐owned dogs with spontaneous atopic dermatitis. Methods – Serum concentrations of calcium, phosphate, creatinine, 25‐hydroxyvitamin D, 1,25‐dihyroxyvitamin D and plasma concentrations of ionized calcium and parathyroid hormone (PTH) were measured, together with the urinary fractional excretion of calcium and phosphate. The extent of skin lesions was scored using the Canine Atopic Dermatitis Extent and Severity Index (CADESI)‐03 and the degree of pruritus by the Edinburgh Pruritus Scale prior to and at the end of the study. Results – The CADESI‐03 and the Edinburgh Pruritus Scale scores decreased satisfactorily in all dogs by the end of the study. Plasma PTH concentrations were significantly increased (P = 0.02) following ciclosporin treatment, whereas all other biochemical parameters were not significantly different from their starting values. The increase in PTH was mild in most cases and the proportion of dogs that had a PTH concentration above the reference range was not significantly different following treatment. Conclusions and clinical importance – This study indicates that ciclosporin has minimal impact on calcium metabolism in dogs with atopic dermatitis when used at the licensed and clinically effective dosage for 6 weeks.     

Pustular dermatosis caused by fire ant (Solenopsis invicta) stings in a dog

This paper reports a case of spontaneous fire ant sting dermatitis in canine. The skin lesions consisted of nonfollicular, grouped pustules in the abdominal region. Several fire ants were found attached to the lesional skin. Histopathological findings included an intraepidermal neutrophilic pustule and predominantly neutrophilic interstitial dermatitis. An extensive area of collagen degeneration was also observed below the epidermal pustule. These clinical and histopathological findings are remarkable similar to those observed in fire ant stings in humans.     

Long‐Term Management with Adipose Tissue‐Derived Mesenchymal Stem Cells and Conventional Treatment in a Dog with Hepatocutaneous Syndrome

Hepatocutaneous syndrome (HS) is an uncommon skin disorder that occurs in conjunction with liver disease and is diagnosed based on decreased plasma concentrations of amino acids and the histopathology of skin lesions. The survival period generally is <6 months. A 10‐year‐old castrated male Maltese dog was presented for evaluation of lethargy, polyuria, polydipsia, and skin lesions including alopecia, erythema, and crusts. Based on increased liver enzyme activity, low plasma amino acid concentrations, and findings from liver cytology and skin biopsy, the dog was diagnosed with HS. In addition to administration of antioxidants, hepatoprotective agents, and amino acids IV, allogenic adipose tissue‐derived mesenchymal stem cells were infused 46 times over a 30‐month period: 8 times directly into the liver parenchyma guided by ultrasonography and the remainder of the times into peripheral veins. After commencing stem cell therapy, the dog's hair re‐grew and the skin lesions disappeared or became smaller. During ongoing management, the patient suddenly presented with anorexia and uncontrolled vomiting, and severe azotemia was observed. The dog died despite intensive care. On necropsy, severe liver fibrosis and superficial necrolytic dermatitis were observed. The dog survived for 32 months after diagnosis. A combination of amino acid and stem cell therapy may be beneficial for patients with HS.     

Ulcerative pododermatitis in a cat associated with Anatrichosoma sp.

A 9-year-old castrated male Chartreaux cat was presented for an ulcerative pododermatitis of all 4 paws. A clinical exam was inconclusive and supportive therapy did not improve the condition. Histologic examination revealed an ulcerative and eosinophilic dermatitis associated with epidermal and dermal nematodes and ova consistent with the aphasmid Anatrichosoma sp. Treatment with ivermectin completely resolved the skin lesions. Anatrichosomiasis should be included in the differential diagnosis of ulcerative pododermatitis in cats, at least in the southwestern United States.     

Interleukin‐31: its role in canine pruritus and naturally occurring canine atopic dermatitis

Background – Interleukin‐31 (IL‐31) is a member of the gp130/interleukin‐6 cytokine family that is produced by cell types such as T helper 2 lymphocytes and cutaneous lymphocyte antigen positive skin homing T cells. When overexpressed in transgenic mice, IL‐31 induces severe pruritus, alopecia and skin lesions. In humans, IL‐31 serum levels correlate with the severity of atopic dermatitis in adults and children. Hypothesis/Objective – To determine the role of IL‐31 in canine pruritus and naturally occurring canine atopic dermatitis (AD). Animals – Purpose‐bred beagle dogs were used for laboratory studies. Serum samples were obtained from laboratory animals, nondiseased client‐owned dogs and client‐owned dogs diagnosed with naturally occurring AD. Methods – Purpose‐bred beagle dogs were administered canine interleukin‐31 (cIL‐31) via several routes (intravenous, subcutaneous or intradermal), and pruritic behaviour was observed/quantified via video monitoring. Quantitative immunoassay techniques were employed to measure serum levels of cIL‐31 in dogs. Results – Injection of cIL‐31 into laboratory beagle dogs caused transient episodes of pruritic behaviour regardless of the route of administration. When evaluated over a 2 h period, dogs receiving cIL‐31 exhibited a significant increase in pruritic behaviour compared with dogs that received placebo. In addition, cIL‐31 levels were detectable in 57% of dogs with naturally occurring AD (≥13 pg/mL) but were below limits of quantification (<13 pg/mL) in normal, nondiseased laboratory or client‐owned animals. Conclusions – Canine IL‐31 induced pruritic behaviours in dogs. Canine IL‐31 was detected in the majority of dogs with naturally occurring AD, suggesting that this cytokine may play an important role in pruritic allergic skin conditions, such as atopic dermatitis, in this species.     

Serum allergen‐specific immunoglobulin E in atopic and healthy cats: comparison of a rapid screening immunoassay and complete‐panel analysis

Feline and canine atopic dermatitis are thought to have a similar immunopathogenesis. As with dogs, detection of allergen‐specific IgE in cat serum merely supports a diagnosis of feline atopy based on compatible history, clinical signs and elimination of other pruritic dermatoses. In this study, a rapid screening immunoassay (Allercept^® E‐Screen 2nd Generation; Heska AG, Fribourg, Switzerland; ES2G) was compared with a complete‐panel serum allergen‐specific IgE assay (Allercept^®; Heska AG; CP) in healthy cats with no history of skin disease and in atopic cats. The latter had no diagnosis of external parasitism, infection, food hypersensitivity or other skin disease explaining their pruritus, and expressed cutaneous reaction patterns typically associated with feline allergic skin disease (head, neck or pinnal pruritus, miliary dermatitis, self‐induced alopecia, eosinophilic granuloma complex). The proportion of cats positive on either the ES2G or the CP assays was not significantly different between the atopic and healthy cat groups. There was, however, strong agreement between the results of the ES2G and CP assay; overall, the two tests were in agreement for 43 of 49 (88%) serum samples. There was also strong agreement when individual allergen groups were evaluated (agreement noted: indoor, 41 of 49 samples; grasses/weeds, 37 of 49 samples; and trees, 41 of 49 samples). These results indicate that although neither test is diagnostic for feline atopic dermatitis, the screening assay is beneficial for predicting the results of a complete‐panel serum allergen‐specific IgE assay in cats.     

Characterization of canine filaggrin: gene structure and protein expression in dog skin

Background – Filaggrin (FLG) is a key protein for skin barrier formation and hydration of the stratum corneum. In humans, a strong association between FLG gene mutations and atopic dermatitis has been reported. Although similar pathogenesis and clinical manifestation have been argued in canine atopic dermatitis, our understanding of canine FLG is limited. Hypothesis/Objectives – The aim of this study was to determine the structure of the canine FLG gene and to raise anti‐dog FLG antibodies, which will be useful to detect FLG protein in dog skin. Methods – The structure of the canine FLG gene was determined by analysing the publicly available canine genome DNA sequence. Polyclonal anti‐dog FLG antibodies were raised based on the canine FLG sequence analysis and used for defining the FLG expression pattern in dog skin by western blotting and immunohistochemistry. Results – Genomic DNA sequence analysis revealed that canine FLG contained four units of repeated sequences corresponding to FLG monomer protein. Western blots probed with anti‐dog FLG monomer detected two bands at 59 and 54 kDa, which were estimated sizes. The results of immunohistochemistry showed that canine FLG was expressed in the stratum granulosum of the epidermis as a granular staining pattern in the cytoplasmic region. Conclusions and clinical importance – This study revealed the unique gene structure of canine FLG that results in production of FLG monomers larger than those of humans or mice. The anti‐dog FLG antibodies raised in this study identified FLG in dog skin. These antibodies will enable us to screen FLG‐deficient dogs with canine atopic dermatitis or ichthyosis.     

Staphylococcus pseudintermedius infection associated with nodular skin lesions and systemic inflammatory response syndrome in a dog

A 10-year-old Pekingese dog with atopic dermatitis was referred due to pyrexia, multiple skin nodules, anorexia, and depression. The dog was diagnosed as having systemic inflammatory response syndrome (SIRS) induced by bacterial dermatitis. This case presents diagnosis and treatment of SIRS with staphylococcal skin infection in a dog that was immunosuppressed due to long-term use of corticosteroid.     

Fermented Maesil (Prunus mume) with probiotics inhibits development of atopic dermatitis‐like skin lesions in NC/Nga mice

Maesil (Prunus mume Siebold & Zucc.), a potential source of free radical scavengers and inhibitor of pro‐inflammatory mediators, is used in traditional Korean medical preparations as a remedy for skin disorders as have probiotics. The action of a probiotic fermented Maesil preparation on the development of atopic dermatitis (AD)‐like skin lesions was determined in a NC/Nga mouse model as an initial step towards the development of a therapeutic feed supplement for use in dogs. Continuous ingestion of the experimental feed markedly inhibited the development of the AD‐like skin lesions, as evidenced by a marked decrease in skin signs and reduced inflammation within the skin lesions. Efficacy was confirmed by significant decreases in eosinophil ratio and serum IgE concentration, and a reduction in the number of Staphylococcus aureus recovered from the ear. Relative mRNA expression levels of IL‐4, interferon‐γ and tumour necrosis factor‐α in the spleens of the experimental animals were also decreased and there was an increased serum concentration of IL‐10 with a concurrent decreased IL‐4 concentration in comparison to a control group. Taken together, the results indicate that some component(s) of fermented Maesil have the ability to suppress the development of AD‐like skin lesions, possibly by stimulation of IL‐10. Beneficial effects of fermented Maesil may thus be expected in dogs with AD, although this and the nature of the active pathway remain to be explored.     

Comparison between IMMUNODOT tests and the intradermal skin test in atopic dogs

This study evaluated a new perspective in the diagnosis of dermatitis in dogs with signs suggestive of allergic skin disease. The results obtained with CMG IMMUNODOT tests using the technique of allergen-specific strip tests, as employed for human allergy diagnosis, were compared with those obtained by the intradermal skin test (IDST). Forty-eight cases completed the diagnostic evaluation, which included IDST, flea-control program, exclusion of sarcoptes and, for some cases, a 1- to 2-month stabilization period on a restricted protein source diet and testing the serum in the presence of allergen-specific IgE and total IgE. The most common disorders included house and storage dust mites, allergic dermatitis and flea-allergic dermatitis together with atopy. This was confirmed serologically. In the case of positive IDST to pollens, Aspergillus spp. and cat epithelium, CMG IMMUNODOT strip tests were negative. A total of 25% of cases were considered to be primarily associated with food hypersensitivity, but only 4% were confirmed serologically. This study emphasizes the value of CMG IMMUNODOT tests as a support in the diagnosis of dog allergy.     

Correlation of histologic and immunologic findings in cats with miliary dermatitis

Eighteen cats with miliary dermatitis were evaluated, using skin testing and histology. Sixteen cats had allergic skin disease (14 cats had positive skin-test reactions to flea antigen [two of which were also atopic], one was atopic only, and one was allergic to beef). In the two remaining cats, the cause of miliary dermatitis was not identified. Histologically, 17 of the cats had superficial eosinophilic dermatitis and epidermal spongiosis, crusting, and ulceration, which were compatible with an allergic cause. Four of these cats had concurrent eosinophilic plaques, which histologically resembled miliary lesions. This overlap of plaques with miliary lesions indicated that when plaques and miliary dermatitis are found concurrently, both lesions may be caused by the same allergens.     

Herpesvirus dermatitis in two cats without facial lesions

Background – Cats with feline herpesvirus (FeHV‐1)‐associated dermatitis typically present with ulcerative lesions on the rostral muzzle and nasal planum. This report describes FeHV‐1 dermatitis in the flank region, in the absence of facial lesions. Hypothesis/Objectives – Clinicians should be aware of this unusual manifestation of FeHV‐1 dermatitis to prevent potential misdiagnosis. Animals – A 12‐year‐old male castrated Bengal cat and a 3‐year‐old male castrated Siamese cat with plaques and ulcers in the flank region are described. Methods – Formalin‐fixed biopsy samples were obtained from lesional skin. Histopathology and FeHV‐1 immunohistochemistry were performed. Results – Each sample had epidermal and follicular necrosis with a dense dermal infiltrate of eosinophils. Few to moderate numbers of intranuclear inclusion bodies were present in keratinocytes. The presence of FeHV‐1 in the lesions was confirmed with immunohistochemistry. Conclusions and clinical importance – Feline herpesvirus‐associated dermatitis should not be ruled out based on the location of the lesion, because a correct diagnosis is imperative for proper treatment. Future studies to assess the cause of lesions at this unusual site are warranted.     

Owner assessment of therapeutic interventions for canine atopic dermatitis: a long-term retrospective analysis

Background – Canine atopic dermatitis is a frequent diagnosis in veterinary medicine; however, the long‐term prognosis for canine atopic dermatitis has not been evaluated in a systematic fashion. Hypothesis/Objectives – To compare the relative efficacy of commonly used therapies for canine atopic dermatitis in two groups of dogs over 5 and 10 year time periods. Animals – Dogs were identified from the medical record database of a privately owned veterinary dermatology practice in the USA. Methods – Clients completed a four‐part, 28‐question, Internet‐based survey. Surveys were included in the analysis if one entire section was completed. Each question was completed independently of the answers to other questions. Results – Several respondents failed to complete all questions. Some respondents answered similar questions with contradictory answers. Each question was analysed individually. A total of 136 owner surveys were completed, 39 from the 10 year and 97 from the 5 year study dogs. Eighty‐five of 135 respondents indicated that their pet was receiving some form of medical therapy for atopic dermatitis at the time of the survey. Thirty of 90 respondents (33.3%) indicated that their dog improved during a dietary trial. Five dogs met the study’s definition for clinical cure. All five of these dogs had been treated with allergen‐specific immunotherapy. Conclusions and clinical importance – This study revealed that clients believe antihistamines can be a useful part of multimodal therapy for canine atopic dermatitis. The results also demonstrated that a significant number of canines benefited from dietary modification. In addition, allergen‐specific immunotherapy was the only treatment to induce true clinical remission of atopic dermatitis.