P‐45 Treatment of allergic feline asthma with allergen avoidance and specific immunotherapy: 20 cats

Twenty cats presented with respiratory signs identified as asthma lasting for several months or years. The episodes of acute coughing and dyspnea were severe, requiring frequent glucocorticoid therapy. An allergic diagnosis was proposed in order to identify the putative allergens involved and to try specific therapy. Three cats developed diabetes mellitus secondary to glucocorticoid treatments. Two of them could not be tested and were given inhalant therapy with bronchodilators and glucocorticoids several times during the day and night. Intradermal tests were performed in 18 cats using 42 aeroallergens. Three tests were negative, even after a second test. Inhalant therapy was prescribed for three cats. Fifteen cats showed positive intradermal test reactions to house dust mites, storage mites and less frequently, pollens. When intradermal test results were positive for storage mites or cockroach, elimination of dried food was first recommended. This was sufficient for remission of the respiratory signs in three cats. Specific immunotherapy was prescribed for the other 12 cats. At the initiation of immunotherapy, all cats were treated with inhaled medications. After 6–9 months, immunotherapy was effective in controlling clinical signs of asthma without any other symptomatic treatment in eight cats. Four cats still required inhaled salbutamol and beclometasone two to three times weekly, instead of two to three times daily. This study demonstrates the role of allergenic stimuli in feline asthma and the advantage of specific immunotherapy as a long‐term treatment. Funding: Self‐funded.     

Sensitization to dust mites in cats with Otodectes cynotis infestation

Sensitization to the dust mites was demonstrated by an intradermal (ID) skin test in 33 of 55 cats with Otodectes cynotis infestation. Positive ID test reactions to Dermatophagoides farinae were noticed in 32 (58.2%), to Dermatophagoides pteronyssinus in 29 (52.7%) and to Acarus siro in seven (12.7%) cats. The presence ( P  = 0.03) and duration ( P  = 0.04) of pruritus were positively associated with the ID test results. All the cats had a complete response to systemic ivermectin therapy, although three of them became reinfested as soon as they were in contact with other cats. The ID test was negative in 25 cats that had reacted positive previously, when the test was repeated 3–6 months after the acaricidal treatment. During that time there was no evidence of concurrent ectoparasitic infestation. The remaining eight cats were re-infested by O. cynotis or lost to follow-up.     

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.     

Treatment of three cats with hyperviscosity syndrome and congestive heart failure using plasmapheresis

Three cats were evaluated at a veterinary teaching hospital for congestive heart failure (CHF) secondary to hyperviscosity syndrome from plasma cell neoplasia. All cats had severe hyperproteinemia due to hyperglobulinemia. Multiple myeloma or plasma cell neoplasia was diagnosed based on cytopathology and post mortem examination. The cats presented with signs of CHF including acute collapse, tachypnea, increased respiratory effort, and pulmonary crackles. All cats had heart murmurs and echocardiographic signs consistent with hypertrophic cardiomyopathy. An enlarged left atrium was found in all cats and two of three cats also had spontaneous echocardiographic contrast. Plasmapheresis (centrifugal plasma exchange) was performed on all three cats by the removal of whole blood and the infusion of a balanced electrolyte solution while the whole blood was centrifuged and separated. The RBCs were then washed before being readministered to the patient. Plasmapheresis alleviated the clinical signs of CHF (tachypnea) in all three cats. Plasmapheresis should be considered in cases of CHF secondary to hyperviscosity syndrome to rapidly alleviate clinical signs associated with heart failure while diagnosis of the underlying cause is made and appropriate therapy implemented.     

The impact of oral versus inhaled glucocorticoids on allergen specific IgE testing in experimentally asthmatic cats

Glucocorticoids (GCs) are palliative for allergic asthma, but allergen-specific immunotherapy (ASIT), which relies on identification of allergens, represents a potentially curative treatment. The purpose of this study was to determine if oral or inhaled GCs would interfere with identification of sensitizing allergens. The hypothesis was that oral but not inhaled GCs would interfere with accurate allergen-specific IgE identification determined by skin and serum testing in experimentally asthmatic cats. Asthma was induced in 18 cats using Bermuda grass allergen (BGA). Cats (n=6/group) were randomized to receive oral GCs (10mg prednisolone q 24 h), inhaled GCs (600 μg budesonide q 24 h) or placebo (q 24 h PO) for one month. Intradermal skin testing (IDST) and serum BGA-specific IgE were measured prior to, during and after treatment. A paired t test was used to compare groups pre- and post-treatment (P<0.05 significant). IDST reactivity was eliminated in 4/6, 3/6, and 1/6 cats receiving oral GCs, inhaled GCs, and placebo respectively. Two weeks after stopping treatment, IDST was again positive in all cats. Serum IgE reactivity to BGA was not significantly diminished by any treatment. In conclusion, a two-week withdrawal from GCs is adequate for IDST, but may not be necessary for serum IgE testing.     

The clinical effect of environmental control of house dust mites in 60 house dust mite-sensitive dogs

Abstract   The purpose of this study was to evaluate the effects of benzyl benzoate, an acaricide for the control of house dust mites, in 60 house dust mite-sensitive dogs. All dogs showed positive reactions on intradermal skin testing for house dust mites ( Dermatophagoides farinae , Dermatophagoides pteronyssinus ) alone, or house dust mites with storage mites ( Acarus siro , Tyrophagus putrescentiae , Glycophagus domesticus ). House dust samples from the owners' houses were collected and sent to the clinic, where the authors performed a test (Acarex® test) to semiquantify the amount of guanine, a house dust mite product. Treatment with benzyl benzoate was repeated until the house dust samples were negative for house dust mite guanine. After treatment, 29 out of 60 house dust mite-sensitive dogs (48%) showed no skin lesions or pruritus. Moderate results were achieved in 22 dogs (36%), with reduced pruritus and minimal skin lesions, but still requiring medication. In 13 dogs, this involved regular treatment (3–4 times a year) with antibiotics and antiyeast medication, and in eight dogs, immunotherapy was used. One dog was controlled with essential fatty acids as monotherapy and one dog was controlled with immunotherapy and essential fatty acids. In the remaining nine dogs (15%), the pruritus remained the same, and these dogs were controlled with oral corticosteroids. These results indicate that house dust mite elimination is a useful tool in the management of house dust mite-sensitive dogs.     

FC-53 Serologic allergy testing in horses with insect hypersensitivity

The usefulness of the intradermal test (IDT) and the serological allergy test (SAT) for detecting antigen-specific IgE in allergic cats has not yet been established. In this study, we compared the results of IDT with those of SAT and evaluated the clinical usefulness of the two tests for detecting possible allergens in allergic cats. IDT and SAT using eight antigens were performed on 22 cats with intense pruritus after excluding ectoparasites and performing diet elimination tests. Approximately 50% of the cats reacted to at least one allergen by either IDT or SAT, and 36.4% of the cats reacted on both IDT and SAT. In contrast, seven healthy cats did not show any reactions on IDT or SAT. The most commonly detected allergen in both tests was house dust mites (IDT, 36.4%; SAT, 40.9%). Five cats reacted to one allergen and the others reacted to more than one allergen with IDT. Three cats reacted to one allergen with SAT. The following percentage agreement between the results of the two tests was calculated: house dust mites (86.4%), cat fleas (63.6%), grass mix (86.4%), common mugwort (81.8%), cat epithelia (90.9%), ragweed (86.4%), Japanese cedar (90.9%), and plantain (81.8%). The overall mean percentage agreement was 83.5%. In summary, the present study showed good agreement between IDT and SAT for cats, and SAT may be more sensitive than IDT, but less specific for detecting sensitized allergens.
Funding: Self-funded.     

FC‐51 Comparison of intradermal test and antigen‐specific IgE test in 22 cases of feline allergic dermatitis

The usefulness of the intradermal test (IDT) and the serological allergy test (SAT) for detecting antigen‐specific IgE in allergic cats has not yet been established. In this study, we compared the results of IDT with those of SAT and evaluated the clinical usefulness of the two tests for detecting possible allergens in allergic cats. IDT and SAT using eight antigens were performed on 22 cats with intense pruritus after excluding ectoparasites and performing diet elimination tests. Approximately 50% of the cats reacted to at least one allergen by either IDT or SAT, and 36.4% of the cats reacted on both IDT and SAT. In contrast, seven healthy cats did not show any reactions on IDT or SAT. The most commonly detected allergen in both tests was house dust mites (IDT, 36.4%; SAT, 40.9%). Five cats reacted to one allergen and the others reacted to more than one allergen with IDT. Three cats reacted to one allergen with SAT. The following percentage agreement between the results of the two tests was calculated: house dust mites (86.4%), cat fleas (63.6%), grass mix (86.4%), common mugwort (81.8%), cat epithelia (90.9%), ragweed (86.4%), Japanese cedar (90.9%), and plantain (81.8%). The overall mean percentage agreement was 83.5%. In summary, the present study showed good agreement between IDT and SAT for cats, and SAT may be more sensitive than IDT, but less specific for detecting sensitized allergens. Funding: Self‐funded.     

Comparison of intradermal testing and serum testing for allergen-specific IgE using monoclonal IgE antibodies in 84 atopic dogs

OBJECTIVE: To compare an ELISA measuring serum allergen-specific IgE with intradermal skin testing in canine atopic dermatitis. PROCEDURE: Eighty-four dogs with the clinical diagnosis of atopic dermatitis underwent intradermal skin testing and serum testing for allergen-specific IgE. Tests were performed in a blinded fashion. Positive reactions were compared and the sensitivity and specificity of the serum test (using intradermal skin test as the standard) were determined overall and for individual allergen groups (grass pollens, weed pollens, tree pollens, house dust mites and fleas). RESULTS: The sensitivity of the ELISA overall was 90.4%. Evaluating the individual allergen groups, the sensitivity for dust mite hypersensitivity was 95.1%, for fleas 85.4%, for tree pollens 84.3%, for grass pollens 95.1% and for weed pollens 96.4%. The specificity was 91.6% overall, for dust mites 96.3%, for fleas 92.7%, for tree pollens 95.2%, for grass pollens 94% and for weed pollens 80.7%. CONCLUSION: The evaluated ELISA seemed reliable for the diagnosis of atopy in practice and can be recommended as a screening test prior to intradermal skin testing or for use in dogs when immunotherapy is not a therapeutic option.     

Redundant arytenoid mucosa: clinical presentation,treatment and outcome in three cats

Three cats showing chronic, intermittent respiratory distress associated with increased noise on inspiration were examined. Head, neck and thoracic radiographs were unremarkable and laboratory findings were within normal ranges. In all three cats direct laryngoscopy revealed bilateral redundant arytenoid mucosa, which collapsed into the supraglottic and glottis airways during inspiration. Temporary tracheostomy and endoscopic diode laser excision of the excessive mucosa resolved symptoms in all three cats. Redundant arytenoid mucosa is a rare condition that may cause signs similar to laryngeal paralysis or laryngeal mass in cats. According to our results, diode laser surgery in association with temporary tracheostomy appears an appropriate mode of therapy.     

Subclinical airway inflammation despite high-dose oral corticosteroid therapy in cats with lower airway disease

Management of feline chronic lower airway disease focuses on controlling clinical signs and decreasing airway inflammation. This retrospective study evaluated the correlation between the resolution of clinical signs in cats with lower airway disease receiving oral glucocorticoids with the resolution of inflammation based on bronchoalveolar lavage fluid (BALF) cytology. Ten cats diagnosed with lower airway disease based on characteristic clinical signs and inflammatory BALF cytology received oral glucocorticoids for at least 3 weeks. They were required to have resolution of clinical signs and BALF collected while asymptomatic and still receiving glucocorticoids. Cats received prednisolone or prednisone (average dose of 1.8±0.2mg/kg daily) for 35.7±5.5 days. Three cats had resolution of clinical signs and lacked inflammatory BALF cytology; seven had persistent inflammatory BALF cytology despite resolution of clinical signs. Given that subclinical inflammation during high-dose glucocorticoid treatment was common, current recommendations to taper therapy based on resolution of clinical signs should be re-evaluated.     

Results of allergen-specific immunotherapy in 117 dogs with atopic dermatitis

The success of the treatment of 117 dogs with atopic dermatitis with allergen-specific immunotherapy for up to 48 months was assessed. An excellent response (remission with exclusive immunotherapy) was recorded in 18 of the dogs, a good response (more than 50 per cent reduction in medication and improvement of clinical signs) was recorded in 57, a moderate response was recorded in 24 and a poor response in 18. The mould antigens in the allergen extract were stored in a separate vial before administration and the success rate of the immunotherapy including mould antigens was much higher than in an earlier study in which mould and pollen antigens had been stored in one vial. The success rate was not affected significantly by the age of the dogs when the disease developed, or by their age or the period for which they had shown clinical signs when the treatment began; it was also unaffected by whether pollens, moulds or dust mites were used as antigens, or by whether the offending allergens had been identified by intradermal testing or by serum testing for allergen-specific immunoglobulin E.     

Effect of short-term oral and inhaled corticosteroids on airway inflammation and responsiveness in a feline acute asthma model

The objective of this study was to investigate whether high-dose inhaled fluticasone propionate (FP), alone or in combination with salmeterol (SAL), is as effective as oral prednisolone in reducing airway inflammation and obstruction in cats with experimentally-induced acute asthma. Six cats sensitised to Ascaris suum (AS) were enrolled in a prospective controlled therapeutic trial and underwent four aerosol challenges, at 1-month intervals with AS allergen. The allergen - stimulated animals received four consecutive days treatment with either oral prednisolone at 1mg/kg twice daily, 500 μg of FP inhaled twice daily, or a combination of FP/SAL at 500 μg/50 μg inhaled twice daily, respectively, according to a randomised cross-over design. Treatment-related changes in lung function, airway responsiveness (AR) and bronchoalveolar lavage fluid (BALF) cytology were assessed. Barometric whole-body plethysmography (BWBP) was used for the assessment of respiratory variables and AR. No significant differences in respiratory rate or Penh (an estimate of airflow limitation measured by BWBP) were detected among treatment groups. Allergen-induced airway hyper-responsiveness was significantly inhibited by all three steroid treatments (P<0.05). The mean BALF eosinophil percentage (±SEM) was lower after oral and inhaled corticosteroid treatment and these changes were significant for groups receiving prednisolone and the FP/SAL combination. Findings suggest high-dose FP, particularly in combination with SAL, is effective in ameliorating airway inflammation and hyper-responsiveness in this model of acute feline asthma, and highlight the potential use of these drugs in cats experiencing acute exacerbations of the naturally occurring disease.     

Efficacy of amoxycillin and azithromycin for the empirical treatment of shelter cats with suspected bacterial upper respiratory infections

Thirty-one cats showing clinical signs of upper respiratory tract disease with a presumed bacterial component based on clinical signs were administered either amoxycillin or azithromycin to determine which drug protocol was optimal for empirical use. A clinical score was determined and nasal and pharyngeal swabs were collected for bacterial culture, virus isolation and polymerase chain reaction prior to the start of therapy. Cats failing to respond to the initial antibiotic were then administered the other drug. There were no differences in clinical scores between the two groups at the start of therapy. Eleven of 31 cats improved after administration of the first antibiotic, 16 cats were switched to the alternate antibiotic, and four cats were removed from the study for additional supportive treatments. Eight of 27 cats failed to respond to either antibiotic. The chi2 test for outcomes revealed no differences in response to therapy for either antimicrobial.     

Pustular calicivirus dermatitis on the abdomen of two cats following routine ovariectomy

An unusual form of calicivirus dermatitis is described in two cats. Two fully vaccinated cats were re-admitted for anorexia and depression following routine ovariectomy. Signs of upper respiratory disease were not present. One cat subsequently showed painful necrosis of the incision wound, the other one developed dyspnoea with pleural effusion and discrete tongue ulcers. Intact pustular lesions confined to the surgically prepared abdomen appeared in both cats, respectively, on days 11 and 9. The histopathological diagnosis was panepidermal pustulosis and necrotizing dermatitis. Positive immunohistochemical staining consistent with feline calicivirus antigen was detected in epithelial cells within pustular lesions. The cats were treated with antibiotics and ketoprofen. The cat with progressive dyspnoea was euthanized. The clinical signs in the other cat rapidly and completely resolved following glucocorticoid therapy. It is hypothesized that the reported cases may represent a distinct calicivirus-induced pustular dermatitis following ovariectomy.     

Lower respiratory tract infections in cats: reaching beyond empirical therapy

PRACTICAL RELEVANCE: Lower respiratory tract infections (LRTIs) in cats can be due to bacteria, parasites, fungi and viruses. This review details the practical investigation of these infections and highlights specific therapy where possible. The aim is to avoid the all-too-frequent temptation in practice to treat cats with lower respiratory tract signs empirically for feline bronchial disease (FBD)/asthma. This is potentially hazardous as immunosuppressive therapy for FBD/asthma could exacerbate disease due to a LRTI. Empirical treatment of suspected LRTI is also difficult to recommend given the wide range of potential pathogens. CLINICAL CHALLENGES: Making a clinical ante-mortem diagnosis of LRTI in a cat can be challenging. Consistent historical, clinical, haematological and radiographic abnormalities are often lacking and findings may be non-specific. Astute clinical acumen, thorough investigation and high quality laboratory analysis are usually required for a diagnosis. Bronchoalveolar lavage, if feasible, and tests for lungworm should be routine in cats with lower respiratory tract signs. Lung fine needle aspiration may be useful in cases of diffuse or nodular pulmonary disease. Histopathology is rarely employed in ante-mortem investigations. EVIDENCE BASE: The authors have reviewed a substantial body of literature to provide information on many of the reported bacterial, parasitic, fungal and viral pathogens, including some that occur in Asia. Attention has been given to specific therapy for each pathogen, with evidence-based comments when there is a deviation from routine recommendations.     

Trilostane therapy for treatment of pituitary-dependent hyperadrenocorticism in 5 cats

Hyperadrenocorticism is a rare syndrome in cats. Current medical therapy is unsatisfactory and prognosis for long-term survival with surgical treatment is guarded. We report on 5 cats treated with the 3-beta hydroxysteroid dehydrogenase inhibitor trilostane. Diagnosis was confirmed in all cats by endocrine testing. Three cats had concurrent diabetes mellitus. Trilostane reduced clinical signs and improved endocrine test results in all cats, but insulin requirements did not change and all continued to have some signs of hypercortisolemia. Two died or were euthanized after 16 and 140 days, whereas 3 were still alive 6, 11, and 20 months after the start of trilostane therapy. Trilostane ameliorates clinical signs of feline hyperadrenocorticism, but more research is needed before it can be recommended for treatment.     

Suppression of cortisol responses to exogenous adrenocorticotrophic hormone, and the occurrence of side effects attributable to glucocorticoid excess, in cats during therapy with megestrol acetate and prednisolone.

The major purpose of this investigation was to determine the effect of prednisolone and megestrol acetate in cats on the adrenal cortisol response to exogenous adrenocorticotrophic hormone during drug administration at dose rates employed for management of some inflammatory feline dermatoses. Prednisolone (at least 2 mg/kg/day) and megestrol acetate (5 mg/cat/day) were each administered orally to seven cats from days 1 to 16. Three additional cats received no therapy. Basal and stimulated cortisol concentrations, food and water intake, hematology, blood biochemistry, urinalyses, and hepatic and cutaneous histology were studied in all cats before, during, and two weeks following the end of treatment. Cats given prednisolone or megestrol acetate had significant suppression of stimulated cortisol levels on day 8. This change was more marked on day 15, when the suppression in cats given megestrol acetate was also significantly more severe than in those receiving prednisolone. Recovery of adrenal reserve was considered present on day 30 in six of seven cats given prednisolone, but in only three of seven receiving megestrol acetate. Eosinopenia, glycosuria and hepatocyte swelling from glycogen deposition were occasionally recorded in treated cats of both groups, providing additional circumstantial evidence for glucocorticoid activity of megestrol acetate in cats. It is advised that abrupt withdrawal of prednisolone or megestrol acetate therapy be avoided in this species to reduce the chance of precipitating clinical signs of hypoadrenocorticism, even after treatment for as little as one week.     

Pneumonia associated with Mycoplasma spp in three cats

Mycoplasma spp were isolated in pure culture from bronchoalveolar lavage specimens from three cats with clinical, cytological and radiographic signs of bron-chopneumonia or suppurative bronchitis. Predisposing factors were not identified in the first case, the second cat had oesophageal hypomotility, while the third cat had been exposed to cigarette smoke and had advanced periodontal disease. Respiratory signs resolved promptly and completely in all cases following antimicrobial therapy directed against mycoplasmas. Mycoplasma spp are possible causes of lower respiratory tract disease in cats and this should be considered when selecting empirical therapy for feline airway disease and pneumonia. In some situations mycoplasmas may behave as primary lower respiratory tract pathogens in cats.     

Pharmacokinetics of enrofloxacin and its efficacy in comparison with doxycycline in the treatment of Chlamydophila felis infection in cats with conjunctivitis

The concentrations of enrofloxacin were measured in the tears, saliva and serum of 14 cats with signs of upper respiratory tract infection and eight with no signs, after daily doses of 5 mg/kg. Enrofloxacin concentrations above the minimum inhibitory concentration of Chlamydophila felis were found in the saliva and tears of the cats with and without signs of upper respiratory tract infection. In a prospective randomised clinical trial, the efficacy of enrofloxacin against C. felis infection in cats with conjunctivitis was compared with the efficacy of doxycycline. Twenty-five cats were randomly assigned to treatment with either enrofloxacin or doxycycline for 14 days; 15 of the cats tested positive for C. felis by an immunofluorescent antibody test on conjunctival swabs. The two treatment groups showed equal improvements in the clinical signs of conjunctivitis and C. felis infection status; in each group three cats were still C. felis antigen-positive after the 14-day course of treatment, indicating a persistent infection. No side effects were observed in the cats treated with enrofloxacin.