A retrospective analysis of case series using home-prepared and chicken hydrolysate diets in the diagnosis of adverse food reactions in 181 pruritic dogs

The purpose of this retrospective study was to compare home-prepared and chicken hydrolysate diets in the diagnosis of canine adverse food reactions (AFR). Seventy-two dogs were fed home-prepared diets and 109 were fed hydrolysate. Owners chose the type of diet at presentation, and ingredients of home-prepared diets were selected depending on each dog's dietary history. Ectoparasitic infestations and microbial infections were treated during the trials. Cutaneous and gastrointestinal signs and pruritus scores were recorded before starting the diet, 6 weeks into the trials and after provocation with the original diets. AFR was diagnosed if pruritus resolved during the trial and recurred on dietary provocation. The dropout rate was lower for home-prepared diets although not statistically significant (18.1% home prepared; 24.7% hydrolysate, P=0.377). AFR alone was diagnosed in 10 dogs (17%) using home-prepared diets and in 15 (18.3%) fed the hydrolysate. Gastrointestinal problems were more frequent in dogs with AFR than in dogs without AFR (P=0.001). Another 11 dogs (18.6%) in the home-prepared diet group and 20 (24.4%) in the hydrolysate diet group had AFR concurrent with other pruritic diseases, mainly atopy. The similar frequencies of AFR diagnosis in the two groups (P=0.837 AFR; P=0.416 concurrent AFR) indicate that the chicken hydrolysate diet may be a valuable alternative to home-prepared diets in the diagnosis of canine AFR. Prospective cross-over studies are warranted to confirm these findings.     

Evaluation of selected-protein-source diets for management of dogs with adverse reactions to foods.

OBJECTIVE: To evaluate 3 commercially available selected-protein-source diets as maintenance diets in dogs with pruritus caused by adverse food reactions. DESIGN: Randomized crossover trial. ANIMALS: 40 dogs > 6 months of age with pruritus caused by adverse reactions to foods. PROCEDURE: Diagnosis was confirmed by use of diet elimination and provocation studies. Subsequently, dogs were fed 3 commercial diets for 3 weeks each in a randomized, blinded, crossover trial. Dogs were evaluated for pruritus, vomiting, diarrhea, and flatulence. RESULTS: Pruritus recurred in 52.5% of dogs fed a chicken-rice diet, 47.5% of dogs fed a catfish-rice diet, and 85% of dogs fed a venison-rice diet. Overall 95% of the dogs could be managed successfully with at least 1 of the 3 diets. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that commercially available limited-allergen diets with selected protein sources may be appropriate for long-term management of pruritus caused by adverse food reactions. Testing of various protein sources is usually required.     

Evalution of a Commerical Canned Lamb and Rice Diet for the Management of Adverse Reactions to Food in Dogs*

Abstract— A commercial canned lamb and rice diet was fed to 20 dogs with previously diagnosed determatologic problems due to adverse reactions to food. Fifteen of the 20 dogs had concurrent atopy and flea allergy which were being treated with hyposensitization and agressive flea control. Palatability and acceptability were good in most of the dogs. Recurrent of previous dermatologic signs did not occur in 75 per cent (15/20) of the dogs while they were fed the diet. Gastrointestinal side effects, specifically diarrhea, caused the owners to stop feeding the diet in four dogs. Overall, 60 per cent (12/20) experienced some gastrointestinal signs during the diet trail.     

Efficacy of a commercial hydrolysate diet in eight cats suffering from inflammatory bowel disease or adverse reaction to food

Eight of 28 cats presenting with chronic vomiting and/or diarrhoea were diagnosed as suffering from chronic enteropathy. All cats had undergone a complete diagnostic work-up, including endoscopy. Histopathology findings varied from normal, eosinophilic, to lymphoplasmacytic gastroenteritis. On the basis of findings, the cats were diagnosed with inflammatory bowel disease (IBD) or an adverse reaction to food. A hydrolysed protein diet was used as sole therapy, and clinical signs resolved within 4-8 days in all eight cats. After 2 months the cats had gained weight. A challenge trial with their previous diet resulted in recurrence of the clinical signs, which resolved in seven cats when the test diet was reintroduced. We conclude that the hydrolysed protein diet used in the current study was effective in managing these cases.     

Food hypersensitivity in 20 dogs with skin and gastrointestinal signs

Canine food allergy can be defined as a non-seasonal, pruritic skin disorder of dogs that is associated with the ingestion of a substance found in the dog's diet. This study records the use of a proprietary dried fish, corn and soyabased diet for the investigation and maintenance of food allergic dogs when fed initially as a restricted allergen diet and then as a maintenance diet after challenge. All the dogs showed evidence of pruritic skin disease and in addition demonstrated gastrointestinal signs. These included the presence of faecal mucus and blood, tenesmus and increased faecal frequency; all the signs associated with colitis. Both cutaneous and gastrointestinal signs resolved when an elimination diet was fed and could be reproduced when the animal was appropriately challenged. Ten dogs were trailed on a home cooked diet of fish and potato and 10 dogs on the proprietary complete food. All the dogs were challenged to identify their food allergies. Nineteen of the dogs have subsequently been successfully maintained on the proprietary food.     

Food sensitivity in cats with chronic idiopathic gastrointestinal problems

The objectives of this study were to investigate the prevalence of food sensitivity in cats with chronic idiopathic gastrointestinal problems, to identify the food ingredients responsible, and to characterize the clinical features. Seventy cats that presented for chronic gastrointestinal signs underwent diagnostic investigation. Fifty-five cats had idiopathic problems and were entered into the study. Diagnosis of food sensitivity was made by dietary elimination-challenge studies by using commercial selected-protein diets as the elimination diet. Sixteen (29%) of the 55 cats with chronic idiopathic gastrointestinal problems were diagnosed as food sensitive. The clinical signs of another 11 cats (20%) resolved on the elimination diet but did not recur after challenge with their previous diet. The foods or food ingredients responsible for the clinical signs were dietary staples. Fifty percent of affected cats were sensitive to more than 1 food ingredient. The clinical feature most suggestive of food sensitivity was concurrent occurrence of gastrointestinal and dermatological signs. Weight loss occurred in 11 of the affected cats, and large-bowel diarrhea was more common than small-bowel diarrhea. Assay of serum antigen-specific immunoglobulin E (IgE) had limited value as a screening test, and gastroscopic food sensitivity testing was not helpful. In conclusion, adverse reactions to dietary staples were common in this population of cats, and they responded well to selected-protein diets. Diagnosis requires dietary elimination-challenge trials and cannot be made on the basis of clinical signs, routine clinicopathological data, serum antigen-specific IgE assay, gastroscopic food sensitivity testing, or gastrointestinal biopsy.     

Food hypersensitivity in 30 dogs

Food hypersensitivity was diagnosed in 30 dogs. Clinical signs varied, with pruritus (97%), erythema (50%), and papules (37%) being the most common. Diagnosis was based on resolution of clinical signs when the dogs were fed a restricted ("hypoallergenic") diet, and recurrence of signs when fed their original diet or other foods. No age, breed, or sex predilection was noticed. None of the owners could relate the onset of clinical signs with a recent change in diet. Seven dogs had concurrent fleabite, inhalant, intestinal parasite, or insulin hypersensitivity.     

Food sensitivity in the dog: a quantitative study

Over a period of one year, 251 dogs were presented to a UK-based dermatology referral clinic. Eighty-five of these were either diagnosed as having symptoms compatible with atopy (58 dogs), or suffered from chronic otitis or recurrent pyoderma. All 85 were placed on a carefully restricted diet for eight to nine weeks in an attempt to establish whether the symptoms were due to food sensitivity. In total, 19 were shown to have food sensitivity, representing 7.6 per cent of all dogs presented to the clinic, and one-third (32.7 per cent) of those dogs with signs compatible with a diagnosis of atopy. In five dogs with proven food sensitivity, otitis was the principal clinical sign and, in two others, recurrent pyoderma. In the population studied, labradors appeared to be predisposed to the condition. Improvement was monitored by asking owners to assess their dog's symptoms on an ordinal scale of pruritus. In those cases in which food sensitivity was confirmed, significant reduction in pruritus occurred. Most of these could be maintained long term on a commercial restricted-component diet. Particular effort was made to ensure owner compliance with the diet trials, using an explanation and model based upon a Venn diagram showing assumed links between atopy and several 'flare factors'. It was found that this approach significantly enhanced client understanding and cooperation. It is concluded that a careful approach, monitored by active clinical audit, will help to establish the true incidence of food sensitivity.     

Systematic review of evidence for the prevalence of food sensitivity in dogs

Twelve papers giving original data on canine food sensitivity in an acceptable form were reviewed, and the disorder was confirmed in 390 dogs. Most of the papers did not give either the criteria by which dogs were included in a trial, or information about dogs which had undergone a trial with a restricted diet but in which food sensitivity had not been observed. Only one author indicated how the degree of pruritus of the dogs in the study was assessed. The question of owner compliance in conducting a diet trial was not considered in any of the papers. The best available evidence comes from three of the studies covering 534 dogs in total, of which 93 (17 per cent) suffered food sensitivity.     

Double-blind evaluation of two commercial hypoallergenic diets in cats with adverse food reactions

The aim of this study was to evaluate two commercially available selected-protein-source diets as maintenance diets in cats with dermatological manifestations of adverse food reactions. Twenty cats with a confirmed adverse food reaction were tested in a double-blind manner. An adverse food reaction was diagnosed when, after recovery with a home-cooked elimination diet, the signs relapsed after a challenge with their previous dietary components, and re-disappeared on a second elimination diet period. Hereafter the cats were blind and randomly challenged with two commercial hypoallergenic diets. Relapse of the clinical signs was seen in eight cats (40%) on a lamb and rice diet and in 13 cats (65%) on a chicken and rice diet (P>0.05).Neither one of the commercial diets was as effective in controlling the skin problems as the home-cooked elimination diet. The study confirms that commercial hypoallergenic diets are adequate for maintenance.     

Diagnosis and management of food allergy and intolerance in dogs and cats

SUMMARY This paper reviews food allergy and intolerance in dogs and cats. Adverse reactions to ingested food components can affect many systems and can produce signs involving the skin, gastrointestinal tract, respiratory tract and central nervous system, and these clinical signs are reviewed. Most basic food ingredients have the potential to induce an allergic response, although most reactions are caused by proteins. In particular, dogs and cats can become sensitive to cow's milk, beef, fish or cereal. Food allergy and intolerance is rare in dogs and cats, although the incidence in practice is difficult to establish. Clinical signs are quite variable, depending on the individual response, although the major clinical sign is pruritus. Diagnosis can be difficult, as there is no single test available to help the clinician to confirm or refute the presence of food sensitivity. Diagnosis is based on dietary investigation in the form of elimination diets and test meals. Elimination diets for dogs include lamb, chicken, rabbit, horse meat and fish as sources of protein, with rice or potatoes. Successful elimination diets for cats include lamb, chicken, rabbit or venison, with rice. Improvement in clinical signs while on the elimination diet is suggestive of food allergy. The diagnosis should be confirmed by feeding the original diet, with the development of clinical signs within 7 to 14 days of feeding.     

Validity of skin testing for diagnosis of food allergy in dogs.

One hundred suspected allergic dogs were skin-tested with 9 food extracts, in addition to other inhalant and insect allergens. Forty-eight of the dogs had +2 or greater intradermal reactions to 1 or more food extracts at concentration of 1,000 protein nitrogen units/ml. Thirty of the food extract-positive dogs were fed a restrictive hypoallergenic diet. Of these 30 dogs, 3 improved, then allergy signs worsened when they were challenge-exposed with the original diet. Fifty-two dogs did not have skin test reactivity to any of the 9 food extracts. Of these 52 dogs, 35 were fed a restrictive diet. Six improved, then allergy signs worsened when dogs were challenge-exposed with the original diet. Skin-testing with selected allergenic food extracts was not useful in identifying food-sensitive dogs.     

Intestinal permeability testing in dogs with diet-responsive intestinal disease

Fifteen dogs with signs of small and, or, large bowel disease that responded clinically to an exclusion diet were studied, using differential sugar absorption as an objective parameter of the mucosal response to the diet. Intestinal permeability and function were assessed by determining the urinary excretion ratios of lactulose/rhamnose and xylose/3-O-methylglucose, respectively, following oral administration of a mixture of these four sugars. Five dogs, all retrievers, were tentatively diagnosed as having dietary hypersensitivity, based upon resolution of clinical signs and normalisation of high intestinal permeability following an exclusion diet and recurrence of signs (in four of five dogs) upon challenge with the original diet. The fifth dog did not become symptomatic when challenged, but intestinal permeability increased. The remaining 10 dogs were diagnosed as having food intolerance, based upon clinical improvement on an exclusion diet, relapse on challenge with their original diet, but lack of improvement in intestinal permeability. These findings suggest that a differential sugar absorption test may be useful to determine the reasons for clinical response to exclusion diets. Demonstration of increased intestinal permeability with subsequent normalization following an exclusion diet may be useful in the diagnosis of dietary hypersensitivity, while persistent abnormalities in intestinal permeability are suggestive of underlying intestinal disease and food intolerance.     

Comparison of a commercial limited-antigen diet versus home-prepared diets in the diagnosis of canine adverse food reaction

The objective of the present study was to compare the efficacy of a commercial limited-antigen diet (Eukanuba Veterinary Diets Response Formula FP/Canine, The Iams Company) with home-prepared diets in the diagnosis of adverse food reaction in dogs. The study was conducted in two phases. The first phase utilized 28 dogs fed a home-prepared diet to enable a diagnosis of adverse food reaction. Dogs diagnosed from this phase were entered into the second phase in which these dogs were fed the commercial limited-antigen diet. Owners of 10 of the 28 dogs quit Phase 1 before it could be completed, and one case was eliminated because extended treatment with steroids was required. Eight of the remaining 17 (47 %) dogs were diagnosed with an adverse food reaction. A reaction occurred in four of eight dogs fed the test diet in Phase 2. These results demonstrated the difficulties encountered by owners and veterinarians attempting to feed dogs home-prepared diets. In addition, the results of the study suggest that the occurrence of adverse reactions to fish could make it a less desirable ingredient as a limited antigenin canine diets.     

A blinded randomized controlled trial evaluating the usefulness of a novel diet (aminoprotect care) in dogs with spontaneous food allergy

Aminoprotect Care (APC) is a novel diet composed of aminoacids, potato proteins and corn starch. The objectives of this study were to determine whether Maltese-Beagle atopic (MBA) dogs hypersensitive to corn exhibited clinical signs and changes in immunological markers after being fed APC. The study was designed as a blinded randomized controlled crossover experiment. Ten MBA dogs with signs of allergy within five days of ingesting corn were selected. Dogs were randomized to be fed either their maintenance diet with corn or APC for five days. After a washout of two weeks, diets were switched. Before and daily during each intervention, skin lesions were graded by an investigator while pruritus was assessed by another. Before and at the end of each intervention, the percentage of circulating CD4+CCR4+, corn-activated CD4+ T-lymphocytes and serum corn-specific IgE levels were measured and ratios of post:pre values calculated. During this trial, pruritus and skin lesions increased significantly in MBA dogs when ingesting corn while no such increase occurred when fed APC. Total, median and maximal pruritus values were significantly higher in MBA dogs ingesting corn compared to APC. There were no significant differences between interventions in the immunological parameters assessed. In summary, even though APC contains corn starch to which corn-sensitive MBA dogs often react, the ingestion of APC did not lead to significant increases in skin lesions or pruritus. Aminoprotect Care might prove valuable for management of food allergies. These experimental observations must be validated in large field studies.     

Dietary hyperthyroidism in dogs

Objectives: Evaluation of dogs with elevated plasma thyroxine concentration fed raw food before and after changing the diet. Method: Between 2006 and 2011 all dogs presented with an elevated plasma thyroxine concentration and a dietary history of feeding raw food were included. Thyroxine (reference interval: 19·3 to 51·5 nmol/L) and in many cases also thyroid-stimulating hormone concentrations (reference interval: <0·30 ng/mL) were measured initially and after changing the diet. Results: Twelve dogs were presented with a median age of five years. The median plasma thyroxine concentration was 156·1 (range of 79·7 to 391·9) nmol/L; in six dogs, thyroid-stimulating hormone concentration was measured and was <0·03 ng/mL in five dogs and 0·05 ng/mL in one dog. Six dogs showed clinical signs such as weight loss, aggressiveness, tachycardia, panting and restlessness while six dogs had no clinical signs. After changing the diet eight dogs were examined: thyroxine concentration normalised in all dogs and clinical signs resolved. Clinical Significance: Dietary hyperthyroidism can be seen in dogs on a raw meat diet or fed fresh or dried gullets. Increased plasma thyroxine concentration in a dog, either with or without signs of hyperthyroidism, should prompt the veterinarian to obtain a thorough dietary history.     

Food hypersensitivity in cats: 14 cases (1982-1987)

Food hypersensitivity was diagnosed in 14 cats. Clinical signs varied; pruritus (100%), alopecia (64%), and papules (21%) were the ones most commonly observed. Pruritus was localized principally to the head or to the neck or ear region in 42% of the cats. Diagnosis was made on the basis of resolution of clinical signs when cats were fed a restricted ("hypoallergenic") diet, and recurrence of signs when cats were fed their original diet or other food. The most common allergens (on the basis of dietary challenge exposure) were fish and dairy products. Age or sex predilection was not observed, and 9 (64%) of the cats were domestic shorthairs. Owners could not relate the onset of clinical signs with a recent change in diet. Three cats had concurrent flea bite, inhalant, or flea collar hypersensitivity.     

Squamous cell carcinoma of the nasal planum in 17 dogs

Squamous cell carcinoma of the nasal planum was diagnosed in 17 dogs over a period of 11 years. Ulceration, bleeding and sneezing were the most common clinical signs. One dog had cytological evidence of metastasis to the local lymph node. The dogs were treated by surgical resection, fractionated megavoltage irradiation, or a combination of the two. Surgical resection gave the most favourable results; four of six dogs were cured but a recurrence of the tumour was predicted in the other two on the basis of incomplete or marginal resection. Radiotherapy alone was not as effective; one of four dogs was cured, and the tumour recurred in the others within 24 weeks (median eight weeks). Combined surgical resection and radiotherapy did not produce a cure in any of the seven remaining dogs, and the tumour recurred within 12 weeks (median nine weeks). Three dogs had cytological evidence of lymph node metastasis when the tumour recurred. The dogs' prognosis was adversely affected by the interval between their initial examination and treatment, but there was no apparent association between the histological grade of the tumour and the clinical outcome.     

The study of canine atopic dermatitis involving the isolation of dogs

Twenty-seven pruritic dogs were used in this study. When a hypoallergenic diet was fed to these 27 dogs for six weeks, none of the dogs showed improvement of the pruritus. These dogs had a history and clinical signs of atopic dermatitis (AD) as defined by Prelaud's diagnostic criteria. Subsequently, the 27 dogs were isolated for observation for two weeks in the hospital. In the isolation room in the veterinary clinic, cages and tableware were all stainless steel, and carpet was not used. A hypoallergenic diet was continuously fed to the 27 dogs for two weeks, during which time they were kept in the isolation room. PVAS (Pruritus Visual Analog Scale) was performed prior to starting the isolation, at the start of the study and 2 weeks after starting the isolation. In 17 dogs (63%) the pruritus improved in the isolation room. A statistically significant reduction (p < 0.01) of PLS (Pruritus liners score) was recorded 2 weeks after isolation. It was hypothesized that the 17 dogs whose pruritus improved in the isolation room had AD caused by an environmental antigen that was not present in the isolation room. Pruritus of the remaining 10 dogs (37%) did not improve. For 6/10 dogs, the intradermal allergy testing was positive for an environmental antigen. For 4/10 dogs, the intradermal allergy testing was negative for all environmental antigens. Dogs for which sensitivity to an environmental antigen was not identified were thought to have atopic-like dermatitis.     

Food allergy and dietary intolerance in dogs: A report of 25 cases

Food allergy or dietary intolerance was diagnosed in 25 dogs. A screening diet of home-cooked chicken and rice was used in all cases except in those dogs which were regularly fed chicken. If an improvement was noted, dogs were then challenged with their original diet and, if relapse occurred, they were suspected of having a diet-related dermatosis. After remission was achieved by again feeding the home-cooked screening diet the animals were provocatively challenged with dietary components. The offending component was a single constituent of the original in 13 of the animals. The age of onset of clinical signs ranged from three months to 10 years and the median age at onset of clinical signs was significantly different from the median age at the hospital. All animals responded to the screening diet within three weeks and none required a period of more than two weeks to respond to provocative challenge. The duration of time between challenge and the onset of clinical signs was significantly different between dogs with intolerance to cereal and those intolerant to dairy products.