Food allergy in the cat: a diagnosis by elimination

PRACTICAL RELEVANCE: Food allergy is recognized as a cause of non-seasonal dermatologic disease and pruritus in cats, though its exact prevalence remains unknown. Feline food allergy can also be associated with gastrointestinal, neurologic, respiratory and behavioral components. PATIENT GROUP: There are no breed, sex or age predispositions for developing food allergy, though there is some evidence that the Siamese and its crosses may be at increased risk. CLINICAL CHALLENGES: Food allergy cannot be diagnosed simply on the basis of the distribution of pruritus, and many of the dermatologic reaction patterns observed in affected cats, such as miliary dermatitis, eosinophilic granuloma complex and alopecia, may be seen in cats with flea allergy and atopy; in some cases, cats may have concurrent allergic conditions. The only way to definitively diagnose food allergy is to identify a causative food component through a food elimination trial. However, palatability and client compliance can each be a problem; specifically, many owners are unwilling to perform a provocation challenge, which is required to confirm a suspected food allergy. For cats in which the existence of a food allergy is confirmed, a suitable maintenance diet then needs to be fed for the remainder of the patient's life. EVIDENCE BASE: Recent literature has revealed that there is marked variability in the clinical picture, response to treatment and outcome in food-allergic cats. This article reviews published literature and highlights clinically relevant observations pertinent to feline food allergy.     

Prospective open pilot study on the use of ciclosporin for feline allergic skin disease

OBJECTIVES: To evaluate the efficacy of ciclosporin in cats with allergic skin disease. METHODS: Ten cats with signs of allergic skin disease were administered ciclosporin daily at a dose of 3.6 to 8.3 mg/kg for one month. None of these cats had previously responded to a hypoallergenic diet trial, and all animals had previously been treated with endectoparasiticidal drugs, with no improvement two weeks before entering the trial. On days 0 and 30, owners assessed pruritus with a visual analogue scale, and veterinarians evaluated cutaneous lesions. RESULTS: All the cats had pruritus and erythema, five had alopecia, two had an eosinophilic plaque, one had miliary dermatitis and two had both alopecia and an eosinophilic plaque. Good or excellent improvement was observed in 40 per cent of cats for pruritus, 57 per cent of cats for alopecia and 60 per cent of cats for erythema. A significant decrease in mean scores was observed for pruritus only, while for erythema and alopecia, it was close to being significant (P < 0.052). CLINICAL SIGNIFICANCE: Ciclosporin may be helpful in symptomatically treating signs of feline allergic skin disease. However, it is important to remember that ciclosporin is not licensed for use in cats.     

Feline atopy in three littermates

This case report describes the history, clinical signs and diagnosis of a pruritic skin disease in three sibling cats living the same household. Clinical signs consistent with pruritus (i.e. hair pulling, hair loss, excessive grooming and face rubbing) were first noted when the cats were 6 months of age. The cats were treated for a possible ear mite and/or flea infestation; there was no response to treatment and clinical signs progressed. Although the presence of pruritus in a multiple cat household suggested an infectious or contagious aetiology, none could be identified. There was no improvement in clinical signs after a 60‐day flea control trial, three treatments of ivermectin, an 8‐week restricted diet or removal from the home for 10 days. A diagnosis of feline atopy was made on the basis of elimination of other causes of pruritus, consistent history and clinical signs, a positive intradermal skin test and response to therapy.     

Retrospective study: the presence of Malassezia in feline skin biopsies. A clinicopathological study

Malassezia spp. dermatitis, a rare disorder in cats, has previously been associated with immune suppression and internal malignancies. This study evaluates the presence and importance of Malassezia spp. in feline biopsy specimens submitted for histopathological examination. Five hundred and fifty haematoxylin and eosin-stained skin biopsy specimens received for histopathological examination between January 1999 and November 2000 were reviewed. Fifteen (2.7%) submissions contained Malassezia organisms in the stratum corneum of the epidermis or follicular infundibulum. Eleven of 15 cats presented with an acute onset of multifocal to generalized skin lesions. All 11 cats were euthanized or died within 2 months of the onset of clinical signs. Seven cats had dermatopathological changes and clinical signs supportive of paraneoplastic alopecia, and three cats had an interface dermatitis suggestive of erythema multiforme or thymoma-associated dermatosis. Histopathological changes were nonspecific in one cat that was euthanized 2 weeks following onset of severe pruritus and alopecia. In three cats, Malassezia spp. were found in localized sites (two chin, one footpads) and appeared inconsequential to their overall health status. One cat had Malassezia spp. in association with cutaneous demodicosis. These findings suggest that Malassezia yeast in dermatopathological specimens from multifocal or generalized lesions should prompt a thorough clinical work-up for internal neoplasia.     

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.     

P-69 Efficacy of cyclosporin in the treatment of feline urticaria pigmentosa: two cases

Few studies have presented general epidemiologic data in veterinary dermatology. The aim of this study was to analyse feline dermatological cases seen at the National Veterinary School of Nantes. Animals presented to the clinics are systematically examined with a protocol that allows validation in a computerized system. Seventy prospective codified parameters are collected at each visit (habitat, nutrition, lesions and localisation, laboratory procedures, hypothesis/diagnosis). The final diagnosis in dermatology may combine several causes or diseases. The study included 783 cases seen from January 1992 to January 1997. The following results indicate the frequency of primary diagnosis and frequency of association or suspicion, respectively. The ten most frequent dermatoses were: flea infestations (24.1/33.3%), flea bite hypersensitivity (22.3/42.9%), dermatophytoses (9.9/26.2%), Otodectes (11.5/19%), food allergy (2.8/25.2%), miscellaneous hypersensitivities (2.8/10%), atopy (2.4/22.4%), miscellaneous external otitis (2.4/5.6%), superficial pyodermas (1.4/4.7%), and psychogenic alopecia (1.3/4.7%). In total, flea-associated problems were identified as the primary cause in 46.5% of cases and hypothesized to be associated in 29% of other cases. Feline miliary dermatitis syndrome was seen in 158 cats (20.2%), feline eosinophilic granuloma complex in 76 cats (9.2%), and extensive alopecia in 58 cats (7.4%).
Funding: Self-funded.     

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.     

P‐67 Characteristics of the 10 most frequent feline skin disease conditions seen in the dermatology clinic at the National Veterinary School of Nantes

Few studies have presented general epidemiologic data in veterinary dermatology. The aim of this study was to analyse feline dermatological cases seen at the National Veterinary School of Nantes. Animals presented to the clinics are systematically examined with a protocol that allows validation in a computerized system. Seventy prospective codified parameters are collected at each visit (habitat, nutrition, lesions and localisation, laboratory procedures, hypothesis/diagnosis). The final diagnosis in dermatology may combine several causes or diseases. The study included 783 cases seen from January 1992 to January 1997. The following results indicate the frequency of primary diagnosis and frequency of association or suspicion, respectively. The ten most frequent dermatoses were: flea infestations (24.1/33.3%), flea bite hypersensitivity (22.3/42.9%), dermatophytoses (9.9/26.2%), Otodectes (11.5/19%), food allergy (2.8/25.2%), miscellaneous hypersensitivities (2.8/10%), atopy (2.4/22.4%), miscellaneous external otitis (2.4/5.6%), superficial pyodermas (1.4/4.7%), and psychogenic alopecia (1.3/4.7%). In total, flea‐associated problems were identified as the primary cause in 46.5% of cases and hypothesized to be associated in 29% of other cases. Feline miliary dermatitis syndrome was seen in 158 cats (20.2%), feline eosinophilic granuloma complex in 76 cats (9.2%), and extensive alopecia in 58 cats (7.4%). Funding: Self‐funded.     

Behavioral dermatology.

The practice of behavioral dermatology encompasses the management of any dermatologic condition for which there is a substantial behavioral or emotional component. Commonly recognized behavioral dermatoses such as acral lick dermatitis, psychogenic alopecia, and hyperesthesia are syndromes rather than discrete diagnoses. Successful patient management is dependent upon integrating physiological, social, and environmental factors which contribute to the clinical manifestation of behavioral dermatoses.     

A survey of canine and feline skin disorders seen in a university practice: Small Animal Clinic, University of Montréal, Saint-Hyacinthe, Québec (1987-1988)

Dermatological disorders accounted for 18.8% and 15.2%, respectively, of all the dogs and cats examined at the Small Animal Clinic, University of Montreal, Saint-Hyacinthe, during a one-year period. In dogs, the most common groups of dermatological disorders encountered were bacterial folliculitis and furunculosis, allergic dermatitis, endocrinopathy, neoplasia, ectoparasitism, and immune-mediated dermatitis. The most common primary final diagnoses were bacterial folliculitis and furunculosis, atopy, food hypersensitivity, flea bite hypersensitivity, hyperadrenocorticism, and hypothyroidism. Breed predispositions were found for several canine dermatoses: bacterial folliculitis and furunculosis (collie, German shepherd, golden retriever, Newfoundland), atopy (boxer, golden retriever), food hypersensitivity (boxer, German shepherd), hyperadrenocorticism (miniature poodle), hypothyroidism (Doberman pinscher, Gordon setter), castration-responsive alopecia (chow chow), demodicosis (Old English sheepdog), and idiopathic pruritus (pit bull terrier).

In cats, the most common dermatoses were abscesses, otodectic mange, cheyletiellosis, flea bite hypersensitivity, atopy, flea infestation, neoplasia, and food hypersensitivity. Himalayan and Persian cats accounted for 50% of the cases of cheyletiellosis and 75% of the cases of dermatophytosis, respectively. Hereditary primary seborrhea oleosa was seen only in Persian cats.

     

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.     

Multiple endocrine neoplasia type-I-like syndrome in two cats

Multiple endocrine neoplasia (MEN) embodies a group of diseases in human patients and domestic animals that are characterized by hyperplasia or neoplasia, or both, of two or more endocrine tissues. The MEN-1 syndrome is associated with menin gene mutations that induce various combinations of parathyroid, pituitary, and pancreatic endocrine tumors in humans. Two male, Domestic Shorthair cats developed symmetric alopecia, insulin-resistant diabetes mellitus, and pituitary-dependent hyperadrenocorticism at 12 and 13 years of age. Examination of skin biopsy specimens revealed atrophic dermatosis associated with hyperadrenocorticism. In one cat, cutaneous lesions consistent with paraneoplastic alopecia associated with pancreatic adenocarcinoma also were evident. Multiple invasive pancreatic beta cell carcinomas, pituitary corticotroph adenomas, and thyroid C-cell and parathyroid chief cell hyperplasia were diagnosed on the basis of results of gross, histologic, and immunohistochemical findings in both cats. Pancreatic exocrine adenocarcinoma was diagnosed in both cats. One cat also had hepatocellular carcinoma. Exons 1-8 of the feline menin gene were sequenced and were found to bear 93% homology with the human gene sequence, and the corresponding amino acid sequences shared 98% homology. Purification of total RNA and amplification of cDNA from lesional tissues to document mutations in the feline menin gene sequence were unsuccessful. The combination of lesions observed was consistent with the diagnosis of MEN-1-like syndrome in both cats.     

Establishment of diagnostic criteria for feline nonflea-induced hypersensitivity dermatitis

Hypersensitivity dermatitides (HD) are commonly seen in cats, and they are usually caused by environmental, food and/or flea allergens. Affected cats normally present with one of the following clinical reaction patterns: head and neck excoriations, usually symmetrical self-induced alopecia, eosinophilic skin lesions or miliary dermatitis. Importantly, none of these clinical presentations is considered to be pathognomonic for HD skin diseases, and the diagnosis of HD is usually based on the exclusion of other pruritic diseases and on a positive response to therapy. The objectives of this study were to propose sets of criteria for the diagnosis of nonflea-induced HD (NFHD). We recruited 501 cats with pruritus and skin lesions and compared clinical parameters between cats with NFHD (encompassing those with nonflea, nonfood HD and those with food HD), flea HD and other pruritic conditions. Using simulated annealing techniques, we established two sets of proposed criteria for the following two different clinical situations: (i) the diagnosis of NFHD in a population of pruritic cats; and (ii) the diagnosis of NFHD after exclusion of cats with flea HD. These criteria sets were associated with good sensitivity and specificity and may be useful for homogeneity of enrolment in clinical trials and to evaluate the probability of diagnosis of NFHD in clinical practice. Finally, these criteria were not useful to differentiate cats with NFHD from those with food HD.     

The effects of clomipramine hydrochloride in cats with psychogenic alopecia: a prospective study

A double-blind, placebo-controlled clinical trial was conducted to determine the efficacy of clomipramine hydrochloride in cats with psychogenic alopecia. Twenty-five cats were randomly assigned to receive clomipramine hydrochloride (0.5 mg/kg orally q 24 hours) or placebo for 56 days. Eleven cats in each group completed the trial. The results of this study showed that clomipramine hydrochloride failed to demonstrate significant changes in the number of grooming bouts, hair regrowth, and the area of alopecia in cats with psychogenic alopecia when compared to a placebo. It was uncertain whether these results reflected a lack of drug efficacy, insufficient treatment duration, or an insufficient number of cases enrolled.     

Clinical characteristics and causes of pruritus in cats: a multicentre study on feline hypersensitivity-associated dermatoses

Hypersensitivity dermatitides (HD) are often suspected in cats. Cats with HD are reported to present with one or more of the following patterns: miliary dermatitis, eosinophilic dermatitis, self-induced symmetrical alopecia or head and/or neck excoriations. Previous reports on feline HD included small numbers of animals, took place in geographically restricted areas or did not compare these conditions with other causes of pruritus. The goal of the present study was to analyse 72 parameters covering signalment, clinical, laboratory and treatment characteristics from a large group of pruritic cats from different geographical areas. Of the 502 cats, the following diagnoses were made: flea HD (29% of cases), food HD (12%) nonflea/nonfood HD (20%) and other diseases in which pruritus was a feature (24%). Cats with signs consistent with a HD but which did not complete a food trial were not analysed further (15% of cases). Most cats with nonflea HD exhibited signs compatible with one or more of the four typical lesional patterns, but none of these patterns was found to be pathognomonic for any specific diagnosis. Food HD and nonflea/nonfood HD were found to be clinically undistinguishable. Young adult, purebred and female cats appeared predisposed to nonflea/nonfood HD. As many diagnoses presented with similar lesional patterns, a thorough clinical work-up is required for establishment of a specific diagnosis.     

犬瘙痒性皮肤病研究进展

瘙痒是犬皮肤病的典型临床症状之一，通常除瘙痒外还常伴脱毛、红斑等皮肤症状。瘙痒问题不仅困扰动物本身，也影响到饲养者的生活质量。瘙痒的发生机制复杂，目前国内外已有大量对人和犬瘙痒性皮肤病的临床和基础研究，揭示了瘙痒和神经免疫系统之间的关系，引入了"瘙痒-抓挠"循环的概念，且表明了免疫系统、皮肤屏障和神经系统的单独促进作用和交互作用是瘙痒产生的关键因素，任一环节的问题都可开启"瘙痒-抓挠"的恶性循环。临床上引起犬瘙痒的病因复杂，参照2007年由国际瘙痒研究论坛成员提出的瘙痒分类，将引起犬瘙痒的疾病根据病因类比对应分为了六大类，引起皮肤病性瘙痒的疾病分为了感染性、过敏性、肿瘤性等，其中在临床上最主要的是犬过敏性瘙痒。犬瘙痒性皮肤病的诊断方法及鉴别诊断多样，需从多方面对患病犬进行信息收集，按一定顺序进行排查和鉴别诊断。犬瘙痒性皮肤病的治疗周期长且疾病易反复，目前常用的西医药物存在副作用大、靶点单一、价格昂贵等不足，中药方剂成分复杂，有效成分多，可从多通路多途径治疗机制复杂的瘙痒，在犬瘙痒性皮肤病的治疗上具有优势和广阔前景。文章对瘙痒发生的机制、犬瘙痒性疾病的分类、诊断及中西医治疗思路等最新研究进展进行综述，以期为小动物临床瘙痒相关疾病的诊治提供参考依据。     

P-89 Aeromonas hydrophila-associated skin lesions and septicaemia in a Nile crocodile

Mites are frequent agents of skin diseases in veterinary dermatology, particularly in rodents. The authors report an original case of infestation in two guinea pigs of the same household. Two adult guinea pigs were presented with a 3-month history of alopecia, matted hair, erythema, scales and mild pruritus. The first guinea pig showed almost complete truncal alopecia with mild scaling, whereas the other one had only recently developed mild alopecia of the abdomen and mild pruritus. Numerous live, long-legged mites were present both in adhesive tape and skin scrapings. Mycology (Wood's lamp and DTM agar culture) was negative. Histopathological examination of a skin biopsy did not reveal any significant inflammatory disease and morphological changes were limited to hair follicles in the telogen phase. Mites were identified as hypopodes of Acarus farris ( Acaridae ), but no adult stages were present. Hypopodes were also found in the hay. Control was obtained with acaricidal treatment with Phoxim 0.05% once weekly for 4 weeks, and the elimination of contaminated hay. The lesions and the alopecia resolved rapidly. Hypopodes are additional nymphal stages of some mites of the suborder Astigmata . They develop for dispersing or dormancy under disadvantageous conditions. They can be active or inert, and some can be phoretic on the skin surface or intrafollicular. Although nonparasitic, they may cause dermatitis. Acarus farris have been rarely mentioned in the literature as a cause of dermatitis. This condition could be underdiagnosed or misdiagnosed in veterinary dermatology.
Funding: Self-funded.     

Use of thoracoscopy to determine the etiology of pleural effusion in dogs and cats: 18 cases (1998-2001)

OBJECTIVE: To assess use of thoracoscopy to determine causes of pleural effusion in dogs and cats. DESIGN: Retrospective study. ANIMALS: 15 dogs and 3 cats with pleural effusion. PROCEDURE: Medical records were reviewed from 1998 to 2001 for dogs and cats that had exploratory thoracoscopy, biopsy, and histologic analysis to determine the etiology of pleural effusion. Intraoperative and postoperative complications were recorded. Surgical biopsy specimens were evaluated for quantity and quality for providing a histologic diagnosis. RESULTS: Biopsy specimens were deemed adequate in quantity and quality to render a histologic diagnosis in all animals. Etiology of the effusion was neoplasia in 8 animals and non-neoplastic pleuritis in 10 animals. Median survival time of animals with neoplasia was 15 days, whereas those with inflammatory diseases had median survival time of > 785 days. Postoperative pneumothorax was encountered in 2 animals subsequent to pulmonary biopsy. No other major complications were recorded. CONCLUSIONS AND CLINICAL RELEVANCE: Thoracoscopy is a diagnostic option that provides excellent viewing of intrathoracic structures and adequate biopsy specimens with minimal complications. This technique provides a less invasive alternative to thoracotomy for evaluating the etiology of pleural effusion.     

Correlation of ultrasonographic appearance of lesions and cytologic and histologic diagnoses in splenic aspirates from dogs and cats: 32 cases (2002-2005)

OBJECTIVE: To determine the accuracy of cytologic diagnosis, compared with histologic diagnosis, in determination of disease in ultrasound-guided fine-needle aspirates of splenic lesions. DESIGN: Retrospective study. SAMPLE POPULATION: Splenic specimens from 29 dogs and 3 cats. PROCEDURES: Records were searched for dogs and cats that had undergone ultrasound-guided splenic aspiration. Criteria for inclusion were ultrasonographic identification of splenic lesions and cytologic and histologic evaluation of tissue from the same lesion. Cytologic samples were obtained by fine-needle aspiration, and histologic specimens were obtained via surgical biopsy, ultrasound-guided biopsy, or necropsy. RESULTS: Cytologic diagnoses corresponded with histologic diagnoses in 19 of 31 (61.3%) cases and differed in 5 of 31(16.1%) cases, and 1 aspirate was inadequate for evaluation. In 7 of 31 (22.6%) cases, histologic evaluation of tissue architecture was required to distinguish between reactive and neoplastic conditions. On the basis of histologic diagnosis in 14 animals with nonneoplastic conditions, the cytologic diagnosis was correct in 11 cases, not definitive in 2 cases, and incorrect in 1 case. In 17 animals with malignant neoplastic diseases, the cytologic diagnosis was correct in 8 cases, not definitive but consistent with possible neoplasia in 5 cases, and incorrect in 4 cases. Multiple similar-appearing nodules were significantly associated with malignancy, whereas single lesions were more often benign. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasound-guided aspiration of splenic lesions is a minimally invasive tool for obtaining specimens for cytologic evaluation. Although cytologic diagnoses often reflect histologic results, if missampling or incomplete sampling occurs or tissue architecture is required to distinguish between reactive and neoplastic conditions, accurate diagnosis with fine-needle aspiration may not be possible.     

Dermatologic disorders in dogs with diabetes mellitus: 45 cases (1986-2000)

OBJECTIVE: To characterize skin lesions and causative infections in diabetic dogs and evaluate other potential causes of dermatologic disorders, including concurrent endocrinopathies, allergic skin disease, and long-term corticosteroid administration. DESIGN: Retrospective study. ANIMALS: 45 dogs with diabetes mellitus (DM) that were examined by dermatologists. PROCEDURE: Medical records were reviewed for signalment; allergic conditions prior to development of DM; prior corticosteroid administration; and results of dermatologic examinations, ear and skin cytologic examinations, skin scrapings for parasites, bacteriologic and fungal culturing of ear and skin specimens, histologic examinations, and endocrine testing. RESULTS: Bacterial skin infection was the most common dermatologic disorder (n = 38 [84%]), followed by otitis (26 [58%]) and Malassezia-induced dermatitis (19 [42%]). Twenty-two (49%) dogs had pruritic skin disease consistent with allergic dermatitis, which preceded diagnosis of DM. Prior corticosteroid administration was reported in 21 (47%) dogs. Concurrent hyperadrenocorticism was diagnosed in 13 (29%) dogs, and concurrent hypothyroidism was diagnosed in 5 (11%) dogs. Iatrogenic hyperadrenocorticism was diagnosed in 1 additional dog. Only 10 (22%) dogs did not have a documented concurrent endocrinopathy or allergic disease that could have caused the dermatitis. CONCLUSIONS AND CLINICAL RELEVANCE: Bacterial and yeast-induced dermatitis and otitis develop in dogs with DM. Many diabetic dogs with dermatologic problems have a preexisting allergic condition, history of prior corticosteroid administration, or concurrent endocrinopathy that may be a more likely cause of dermatologic problems than DM alone.