food allergy in dogs and cats acvim 2004 new insights

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food allergy in dogs and cats acvim 2004 new insights

Postby malernee » Tue Oct 05, 2004 1:30 pm

Food Allergy in Dogs--New Insights
ACVIM 2004
Karin Allenspach, DMV, DECVIM-CA (Internal Medicine)
Bern, Switzerland


A significant number of dogs with chronic diarrhea, vomiting and weight loss respond favorably to treatment with elimination diet and are therefore suspicious for being food allergic 1-4. Clinically, it is difficult to discern food intolerance from a true food allergy. Per definition, in food allergy, an immunologic reaction in the intestine takes place that causes the clinical signs. The prevalence of true food allergy in dogs with gastrointestinal signs is largely unknown, as most published reports describe dogs with dermatologic symptoms 4-6. The knowledge on the pathogenesis of food allergy in dogs is scarce and is believed to involve type I hypersensitivity reactions as well as late type reactions (type II and IV).


In people, the diagnosis of food allergy is made by taking a history, performing serologic as well as skin tests, and finally, performing a double-blind placebo controlled food challenge containing the protein of question7. All of these diagnostic tools detect a possible type I hypersensitivity reaction, which is supposedly the most common form of food allergy in people. A new test, the colonoscopic allergen provocation (COLAP) has recently been described, where the potentially offending food allergens are injected into the colonic mucosa and a mucosal wheal and flare reaction is evaluated to assess the possibility of a type I reaction in the intestinal mucosa8. This test has been shown to correlate very well with the history of food allergy in human beings9.

The diagnosis of food allergy in dogs remains difficult due to the lack of diagnostic tests available. The gold standard of a diagnosis is the oral food challenge test. During this test, potentially offending food containing the suspicious protein is given to the dog over 2-4 days and a reaction comprising gastrointestinal signs (vomiting, diarrhea, inappetence) or skin signs (pruritus) is observed 6,10,11. This test is difficult to perform and allows a wide range of interpretation. It is debatable if the clinical signs seen during such an oral challenge test are due to a type I hypersensitivity reaction, since some reactions take several weeks to develop. However, recent information on the distribution of mast cells, IgE and IL-4-mRNA and -protein in the intestine of dogs diagnosed with inflammatory bowel disease has provided insights into possible IgE-mediated immune reactions in the canine intestinal tract12. Type I hypersensitivity reactions are still the easiest ones to detect since IgE measurements and direct allergy tests are available for dogs. The critical assessment of such tests in larger studies and larger populations of dogs with suspected food allergic reactions is necessary to assess the diagnostic utility of such tests in the future.


Gastroscopic food sensitivity testing (GFST) has been described in healthy and clinically suspected food allergic dogs13,14 as well as in a colony of food allergic Soft Coated Wheaten Terriers (SCWT)13-15. During this technique, allergen solutions are dropped onto the greater curvature of the stomach while performing endoscopy. The test is technically difficult to perform, and the mucosal response is inconsistent as well as difficult to interpret because allergen extract could run off the application site. The GFST appears insensitive: it detected only a relatively small percentage of positive reactions seen during an oral challenge test in food allergic research dogs (8/42 positive reactions or 19%)15. However it had a good specificity, as many of the positive reactions could be confirmed by oral challenge in other studies13-15.

The colonoscopic allergen provocation (COLAP) has recently been described to help diagnose food allergy in adults with possible adverse reactions against food8,9. During this test, the food allergens are injected into the colonic mucosa and a mucosal wheal and flare reaction is evaluated to assess the possibility of an immediate type I reaction. The COLAP technique has been previously applied in a research allergy model using atopic dogs and showed a good reproducibility when performed a second time on the same animals16.

Our preliminary experience with the COLAP test has been promising. We have validated this test in 9 dogs of a research colony of SCWT at North Carolina State University. These dogs have been challenged with the allergens used in the COLAP and in a previously performed GFST. The results of GFST and COLAP tests were compared to the observations made during oral challenges as a gold standard.

The COLAP proved to be a reliable method, with a sensitivity and specificity of 0.75 (95% CI: 0.51; 0.90) and 0.73 (95% CI 0.54; 0.86), respectively. For the GFST, sensitivity and specificity were 0.32 (95% CI 0.14; 0.57) and 0.6 (95% CI 0.41; 0.77), respectively, in the same food allergic dogs.

We also applied the COLAP to 22 clinically suspicious food allergic dogs prospectively enrolled into a clinical study. The dogs in this study showed symptoms of chronic intermittent diarrhea of at least 6 weeks duration, as well as non-seasonal pruritus in some of them (6/22). The dogs were treated with an elimination diet based on salmon and rice and all of them showed complete resolution of clinical signs after 14 weeks of sole dietary treatment. The dogs were fasted 48 hours before endoscopy and prepared routinely for colonoscopy. Injection sites for the allergens were selected in a clockwise fashion around the ileocolic valve. Extracts of beef, lamb, chicken, wheat and cow milk were used as allergens. In addition, 0.9% NaCl and histamine were used as negative and positive control, respectively. The injection sites were observed for 15 Minutes after each application. The reaction was interpreted as positive when clearly demarcated swelling, edema, and hyperemia were observed. A total of 32 tests were performed, and in 10 dogs, the test was repeated after feeding an elimination diet for 14 weeks. 5/32 tests were not interpretable, because either the histamine was not positive or the NaCl control was inclusive. In 21/22 dogs tested, the COLAP was positive for at least one allergen. The most frequent reactions to injected allergens were seen with beef (19/22), chicken (14/30), cow milk (12/30), lamb (11/32) and wheat (9/30). So far, only a few of the clinical dogs have been tested by oral challenging to confirm the presence of food allergy. Since the COLAP test showed good accuracy in proven food allergic research dogs, this test may represent an alternative to oral challenge testing in the future.


Among the tests to diagnose food allergy in man, food allergen specific IgE measurement using radioimmunosorbent assays (RAST) has a very low sensitivity and specificity of 30-50%,17 compared to skin prick tests that show a sensitivity of up to 81%.18 Measurement of total IgE in dog serum has been shown to depend on age and breed of dogs and therefore, this test does not seem to be helpful in the diagnosis of any allergic diseases in dogs.19 Only very few studies are published to this date that evaluated commercially available assays for serologic food allergen-specific IgE in dogs. These studies prove the tests to be insensitive, unspecific and therefore unreliable for the diagnosis of food allergy in dogs.20 A recently published test measuring food allergen specific IgE levels in the feces seemed to correlate best with oral challenge test results in proven food allergic research dogs.15


1. Paterson S. Food hypersensitivity in 20 dogs with skin and gastrointestinal signs. J Small Anim Pract 1995; 36(12):529-534.

2. German AJ, Hall EJ, Day MJ. Immune cell populations within the duodenal mucosa of dogs with enteropathies. J Vet Intern Med 2001; 15(1):14-25.

3. Jergens AE, Moore FM, Haynes JS, Miles KG. Idiopathic inflammatory bowel disease in dogs and cats: 84 cases (1987- 1990). J Am Vet Med Assoc 1992; 201(10):1603-1608.

4. Guilford WG. Adverse reactions to food: A gastrointestinal perspective. Compendium on Continuing Education 1994; 16(8):957-968.

5. Hall EJ. Gastrointestinal aspects of food allergy: A review. J Small Anim Pract 2002; 34:145-152.

6. White SD. Food Allergy in Dogs. The Compendium 1998; 20:261-268.

7. Bischoff SC, Mayer JH, Manns MP. Allergy and the gut. Int Arch Allergy Immunol 2000; 121(4):270-283.

8. Bischoff SC, Mayer J, Wedemeyer J, Meier PN, Zeck-Kapp G, Wedi B et al. Colonoscopic allergen provocation (COLAP): a new diagnostic approach for gastrointestinal food allergy. Gut 1997; 40(6):745-753.

9. Bischoff SC, Mayer J, Meier PN, Zeck-Kapp G, Manns MP. Clinical significance of the colonoscopic allergen provocation test. Int Arch Allergy Immunol 1997; 113(1-3):348-351.

10. Rosser EJ, Jr. Diagnosis of food allergy in dogs. J Am Vet Med Assoc 1993; 203(2):259-262.

11. August JR. Dietary Hypersensivity in Dogs: Cutaneous manifestations, Diagnosis, and Management. The Compendium on continuing education 1985; 7(6).

12. Locher C, Tipold A, Welle M, Busato A, Zurbriggen A, Griot-Wenk ME. Quantitative assessment of mast cells and expression of IgE protein and mRNA for IgE and interleukin 4 in the gastrointestinal tract of healthy dogs and dogs with inflammatory bowel disease. Am J Vet Res 2001; 62(2):211-216.

13. Guilford WG, Strombeck DR, Rogers Q, Frick OL, Lawoko C. Development of gastroscopic food sensitivity testing in dogs. J Vet Intern Med 1994; 8(6):414-422.

14. Elwood CM. Gastroscopic food sensitivity testing in 17 dogs. Journal of Small Animal Practice 1994; 35:199-203.

15. Vaden SL, Hammerberg B, Davenport DJ, Orton SM, Trogdon MM, Melgarejo LT et al. Food hypersensitivity reactions in Soft Coated Wheaten Terriers with protein-losing enteropathy or protein-losing nephropathy or both: gastroscopic food sensitivity testing, dietary provocation, and fecal immunoglobulin E. J Vet Intern Med 2000; 14(1):60-67.

16. Puhl S, Pickert CN, Neiger-Aeschbacher G, Welle M. Tackling the problem of diagnosing food allergy in dogs: colonoscopy allergen provocation (COLAP), an additional tool. The European Journal of Comparative Gastroenterology 1999; 4(June 1999):17-23.

17. Boccagni P, Favari F, Zanoni G, Pezzini A, Tridente G. Comparison of 4 In-Vitro Assays for Specific Ige Detection. International Journal of Clinical & Laboratory Research 1994; 24(2):102-105.

18. Rance F, Abbal M, Lauwers-Cances V. Improved screening for peanut allergy by the combined use of skin prick tests and specific IgE assays. Journal of Allergy and Clinical Immunology 2002; 109(6):1027-1033.

19. Racine BP, Marti E, Busato A, Weilenmann R, Lazary S, Griot-Wenk ME. Influence of sex and age on serum total immunoglobulin E concentration in Beagles. Am J Vet Res 1999; 60(1):93-97.

20. Jeffers JG, Shanley KJ, Meyer EK. Diagnostic testing of dogs for food hypersensitivity. J Am Vet Med Assoc 1991; 198(2):245-250.

Speaker Information
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Karin Allenspach, DMV, DECVIM-CA (Internal Medicine)
Veterinary I.M.
University of Bern
Langgassstrasse 124
Site Admin
Posts: 462
Joined: Wed Aug 13, 2003 5:56 pm

Canned diets may not be ideal for enteritis study

Postby guest » Fri Jan 07, 2005 8:52 am

Evaluation of the immunogenicity of dietary proteins in cats and the influence of the canning process.
Am J Vet Res 65[10]:1427-33 2004 Oct

Cave NJ, Marks SL
OBJECTIVE: To characterize the antigen-specific immune response to dietary proteins in cats and evaluate whether there was a qualitative or quantitative difference between the responses to dietary proteins when those proteins were fed unprocessed or as part of a canned diet. ANIMALS: 14 healthy domestic shorthair cats. PROCEDURE: Cats were fed 2 dietary proteins (soy and casein) either as unprocessed aqueous suspensions or as part of canned diets for 21 days. Serum IgG and IgA and salivary IgA were assayed by indirect ELISA, and antigen-specific proliferation of mesenteric lymph node-derived lymphocytes was determined. RESULTS: Robust serum IgG and IgA responses to dietary proteins were elicited, irrespective of the form in which they were fed. Salivary IgA responses to unprocessed proteins were not detected. However, a significant salivary IgA response to the protein isolated from the canned casein diet was observed in cats fed canned casein but not in those fed unprocessed casein. Lymphocyte proliferation to the antigens was slight, and there were no significant differences between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that cats develop robust serum IgG and IgA responses to dietary proteins when fed as either aqueous suspensions or as part of canned diets. For certain proteins, there may be an increase and a qualitative difference in the immunogenicity of canned diets, compared with unprocessed proteins. Canned diets may not be ideal for management of cats with enteritis.

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