Nonthymoma-associated exfoliative dermatitis in 18 cats.

BACKGROUND: Exfoliative dermatitis has been described in cats as a paraneoplastic skin disease associated with thymoma. There are anecdotal reports of cases without thymoma, with various suspected aetiologies. HYPOTHESIS/OBJECTIVES: To identify common features, underlying causes, response to therapy and outcome of nonthymoma-associated exfoliative dermatitis in cats. METHODS: Retrospective analysis was carried out of cases presented to dermatology referral centres or cases submitted for histopathological examination. Detailed historical and clinical data were obtained and evaluated statistically. Histopathology was reviewed in a blinded fashion by three dermatopathologists, and PCR for herpesvirus was performed. RESULTS: Eighteen cats fulfilled all inclusion criteria. There was no sex, age or breed predisposition. All cats presented with severe generalized (77%) or multifocal exfoliation (23%); 12 cats were severely depressed. In all cats, thymoma was excluded radiographically and feline leukaemia virus tests were negative. Additional imaging procedures in 14 cats and postmortem examination in two cats did not detect neoplasia. Histopathology revealed interface dermatitis, mural interface folliculitis and sebaceous adenitis indistinguishable from findings in thymoma-associated cases. PCR for herpes DNA was negative. No aetiology was identified. Treatment in 12 cases consisted of immunosuppressive doses of corticosteroids and/or ciclosporin; one responded to antibiotics, one to shampoo, two went into spontaneous remission, and two did not receive any therapy and were euthanized. CONCLUSIONS AND CLINICAL IMPORTANCE: Nonthymoma-associated exfoliative dermatitis in cats is clinically and histopathologically indistinguishable from thymoma-associated cases. Most cases benefit from immunosuppressive therapy; therefore, an immunopathological response to an undefined trigger is suspected.

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.

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.

A multicentre placebo-controlled clinical trial on the efficacy of oral ciclosporin A in the treatment of canine idiopathic sebaceous adenitis in comparison with conventional topical treatment.

Canine idiopathic sebaceous adenitis (ISA) is an inflammatory reaction of sebaceous glands, potentially resulting in their complete loss. It is considered a T-cell-mediated disease, but its precise pathogenesis is still unknown. Topical treatment with oil soaks, humectants and shampoos is effective but laborious. Ciclosporin A (CsA), an immunomodulatory drug, has recently been shown to ameliorate the clinical picture of ISA and to reduce inflammation greatly. It is, however, an expensive treatment option. The objective of this multicentre, partly double-blinded, randomized controlled study was to evaluate the efficacy of ciclosporin A, either alone or with topical therapy, in comparison to conventional topical treatment alone, as measured by the primary end-points alopecia and scaling, and multiple histopathological secondary objectives. Thirty-four dogs with an established diagnosis were treated for 4-6 months and were evaluated before, during and after therapy. Both CsA and topical therapy demonstrated efficacy in this study. Differences between the treatment protocols were marginal. Topical treatment, both alone and in combination with CsA, appeared to reduce scaling more effectively than CsA alone. Both therapies reduced alopecia. There is evidence of a synergistic benefit on both scaling and alopecia, if both treatment options are combined. Inflammation of the sebaceous glands is also best reduced by a combination of both CsA and topical therapy. There is evidence that regeneration of sebaceous glands is best achieved by CsA, either given alone or in combination with topical treatment.

Immunization of Cats against Fel d 1 Results in Reduced Allergic Symptoms of Owners.

An innovative approach was tested to treat cat allergy in humans by vaccinating cats with Fel-CuMV (HypoCatTM), a vaccine against the major cat allergen Fel d 1 based on virus-like particles derived from cucumber mosaic virus (CuMV-VLPs). Upon vaccination, cats develop neutralizing antibodies against the allergen Fel d 1, which reduces the level of reactive allergen, thus lowering the symptoms or even preventing allergic reactions in humans. The combined methodological field study included ten cat-allergic participants who lived together with their cats (n = 13), that were immunized with Fel-CuMV. The aim was to determine methods for measuring a change in allergic symptoms. A home-based provocation test (petting time and organ specific symptom score (OSSS)) and a general weekly (or monthly) symptom score (G(W)SS) were used to assess changes in allergic symptoms. The petting time until a pre-defined level of allergic symptoms was reached increased already early after vaccination of the cats and was apparent over the course of the study. In addition, the OSSS after provocation and G(W)SS recorded a persistent reduction in symptoms over the study period and could serve for long-term assessment. Hence, the immunization of cats with HypoCatTM (Fel-CuMV) may have a positive impact on the cat allergy of the owner, and changes could be assessed by the provocation test as well as G(W)SS.

Results of clinical examinations, laboratory tests, and ultrasonography in dogs with pituitary-dependent hyperadrenocorticism treated with trilostane.

OBJECTIVE: To determine the efficacy of trilostane, a 3beta-hydroxysteroid dehydrogenase inhibitor, in dogs with pituitary-dependent hyperadrenocorticism (PDH). ANIMALS: 11 dogs with PDH. PROCEDURE: The initial dose of trilostane was 30 mg, PO, q 24 h for dogs that weighed < 5 kg and 60 mg, PO, q 24 h for dogs that weighed > or = 5 kg. A CBC count, serum biochemical analyses, urinalysis, ACTH stimulation test, and ultrasonographic evaluation of the adrenal glands were performed in each dog 1, 3 to 4, 6 to 7, 12 to 16, and 24 to 28 weeks after initiation of treatment. RESULTS: All dogs responded well to treatment. All had reductions in polyuria-polydipsia and panting and an increase in activity. Polyphagia decreased in 9 of 10 dogs, and 9 of 11 dogs had improvement of coat quality and skin condition. Concentration of cortisol after ACTH stimulation significantly decreased by 1 week after initiation of treatment. After treatment for 6 months, clinical signs resolved in 9 dogs. In the other 2 dogs, marked clinical improvement was reported for 1 dog, and moderate improvement was reported in the other dog. Ultrasonographically, there was a considerable change in the parenchyma and an increase in size of the adrenal glands. Adverse effects consisted of 1 dog with transient lethargy and 1 dog with anorexia. CONCLUSIONS AND CLINICAL RELEVANCE: Trilostane is an efficacious and safe medication for treatment of dogs with PDH. Additional studies in a larger group of dogs and characterization of progressive changes in adrenal glands are needed.

Evaluation of intravenous fluorescein in intradermal allergy testing in psittacines.

This study was designed to improve the clinical feasibility of intradermal skin testing of psittacine birds using intravenous fluorescein stain. Twenty-five healthy, anaesthetized Hispaniolan Amazon parrots (Amazona ventralis) were injected intravenously with 10 mg kg-1 fluorescein-sodium 1% followed by intradermal injections of 0.02 mL phosphate-buffered saline, histamine phosphate (1:100,000 w/v) and codeine phosphate (1:100,000 w/v) at the sternal apteria. Wheal diameters of reaction sites were measured grossly and under illumination with a Wood's lamp after 5 and 10 min. Fluorescence-enhanced injection sites were scored between 0 and 2, with 0 equivalent to normal skin and 2 equivalent to a plucked feather follicle. The presence of a fluorescent halo around intradermal injections was also recorded. Under Wood's light illumination at 10 min, histamine and saline were evaluated as positive and negative controls, respectively, based on a positive test having a halo and a score of 2. Sensitivity and specificity were each 76% for halo, 84 and 42% for score and 64 and 77% for combination of score and halo, respectively. Further, mean histamine reactions were significantly larger than codeine phosphate and saline (8.8 +/- 0.4 mm; 7.2 +/- 0.3 mm; 5.9 +/- 0.6 mm); however, this finding was not consistent in individual birds. Wheal size, halo presence and score were affected by site location independent from the injected compound. Intravenous fluorescein improved the readability of avian skin tests; however, the compounds tested raised inconsistent reactions in wheal size, score or halo presence. The compound-independent site effect raises concern on the validity of avian skin testing and warrants investigation of other techniques such as in vitro allergy testing. Based on our findings, intradermal allergy testing in psittacines with or without fluorescein is unreliable and cannot be recommended for practical clinical use.