Dog allergy to meat: is IDT and specific IgE of any usefulness?

Abstract

Introduction: Cutaneous adverse food reactions are a current problem in dogs, with beef, dairy products, chicken and wheat as the most implicated food components. As in humans, cutaneous and serological tests do not show enough individual diagnostic reliability for the diagnosis of food allergy. A wider diagnosis approach, including dietary restriction-provocation trials, is often necessary. Methods: From 85 dogs attending the Veterinary Hospital of the University of Évora (Portugal) and Rof Codina University Hospital (Lugo, Spain) outpatient consultations, 11 (5 males and 6 females) were selected by means of clinical inquiry and IDT for probable food allergy. All of them presented with pruritic dermatitis and at least 6 of the Favrot’s criteria for atopic dermatitis. None of them showed noticeable digestive signs. IDT were performed for D. glomerata, P. pratense, D. farinae, D. pteronyssinus, A. siro, T. putrescentiae, L. destructor, beef, pork, lamb, chicken, egg and milk. Specific IgE panels were determined in a commercial lab for pollens, molds and mites. Assessment of specific IgE for beef, pork, lamb, chicken, egg and milk was performed in Dot Blots with mouse anti-dog IgE McAb. Results: Mean specific IgE (EAU) was Dac g=547, Phl p=601, Der f=1665, Der p=297, Aca s=2063, Tyr p=1644 and Lep d=105. IDT were found positive in 4 patients (Dac g), 3 (Phl p), 5 (Der f), 6 (Der p), 4 (Aca s), 1 (Tyr p), 3 (Lep d), 10 (beef), 5 (pork), 5 (lamb), 6 (chicken), 4 (egg) and 2 (milk). Specific IgE Dot Blots showed positive for all patients to beef, pork and lamb, and in 8 of them to chicken. Semi-quantitation was found possible in Dot Blots. Strong positive correlation was observed between specific IgE and IDT to Der p (p=0.048), IDT and Dot Blots to beef (p=0.015) and to chicken (p=0.0003), and the intensity of Dot Blots between beef and lamb (p=0.006). Semi-quantitative difference was found between meat sources for mean IDT/Dot Blots scores: beef (3.2/3.73), pork (3/3.27), lamb (1.8/2.91) and chicken (1.8/1.3). In dogs presenting positive IDT to beef, pork, lamb or chicken, avoidance of those specific meats was recommended, with significant clinical improvement, especially when beef or chicken were implicated. Conclusion: IDT and specific IgE as less invasive and quicker diagnosis tools, may, along with dietary restriction-provocation trials, be useful for the diagnosis of food allergy as in several clinical cases positive results revealed to be predictive.