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FOOD HYPERSENSITIVITY IN A SMALL ANIMALS CLINIC: Laboratory tests as a
diagnostic method for detecting allergens
Author: Mayra Ferreira Poitena
RESUME
This case study aims to verify the effectiveness of the results of food hypersensitivity tests
as a diagnostic method by analyzing the immune response in four dogs and one cat with
symptoms suggestive of the diagnosis: digestive, respiratory, neurological and
dermatological. After the results, the animals were submitted to natural diets without
including the foods that resulted positive in IgE, IgG, IgA and IgM in the tests. The five
animals submitted to the exams responded favorably with complete or partial remission of
symptoms.
Keywords: Food hypersensitivity. Elimination diet. Immunoglobulins.
1 INTRODUCTION [Primary Section]
Exams for detecting Food Hypersensitivity in Veterinary Medicine are little used in
clinical practice due to little clinical response by the patient when positive foods in IgG or
IgE are removed after blood test results. The blood test has the characteristic of identifying
the immune response of both immunoglobulins specifically, however, it does not reveal the
immune response of IgA and IgM, the latter two also being responsible for generating a
chronic inflammatory reaction of food hypersensitivity.
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1 Article submitted to the Brazilian Institute of Advanced Resources - IBRA, as part of the requirements for obtaining the
postgraduate degree in Diet Therapy and Nutraceuticals, in 2021 and 2022.
2 Postgraduate in Diet Therapy and Nutraceuticals by IBRA – E-mail: m.poitena@biovet.es
2 THE DEVELOPMENT OF THE SCIENTIFIC ARTICLE: OBJECTIVE AND
METHODOLOGY [Primary Section]
This case study aims to verify the effectiveness of the results of food
hypersensitivity tests when performed together, that is, when the request for detection
tests includes both IgG and IgE, as well as IgA and IgM.
Four animals of the canine species and one of the feline species with different
chronic symptoms (digestive, dermatological, respiratory and neurological) were submitted
to food hypersensitivity tests and foods positive for IgG, IgE, IgA and IgM were removed
from their diets.
2.1 Development Subsection [Secondary Section]
Of the four canine individuals, one manifested itching and chronic diarrhea (German
Shepherd female, 12 months old), another had only chronic digestive conditions, mainly
diarrhea (Golden Retriever female, 11 months old), the third expressed both symptoms, or
that is, both digestive and dermatological, such as alopecia, intense pruritus and diarrhea
(six-year-old SRD male) and the fourth with intense and frequent epileptic seizures
medicated with Phenobarbital (6-year-old SRD male). The feline patient had vomiting,
conjunctivitis and chronic sneezing, as well as focal alopecia near the ear canal (8-year-
old British female).
No animal was submitted to the elimination diet for diagnosis and all of them were
derived from food hypersensitivity tests.
In 100% of the patients the result was positive in the blood test for IgE, 40% for IgG
and 100% for hair and saliva tests that include IgA and IgM.
For all animals, food with a positive result for IgE, IgG, IgA and IgM was removed.
Three of the four dogs were treated with properly cooked and balanced homemade
diets and one was given a commercial raw bone diet. The feline patient ingested
commercial wet food.
All food plans were properly calculated for each individual, ensuring the supply of all
essential micronutrients. A lipidogram with an anti-inflammatory profile was also applied.
All patients underwent intestinal modulation treatment.
2.1.1 Citations [Tertiary Section]
For A Verlinden, M Hesta, S Millet and G P J Janssens, a reliable diagnosis can
only be made with challenge and elimination tests, as it is only through provocation that
the causative food components can be identified. (Verlinden et al., 2006)
According to J Wills and R Harvey (1994) the diagnosis can be difficult, since there
is no single test available to help the veterinarian to confirm or refute the presence of food
sensitivity. Diagnosis is based on dietary investigation in the form of elimination diets and
test foods. (Wills et al., 1994)
In contrast, Jacqueline Bryan and Linda A Frank state that due to clinical
challenges, food allergy cannot be diagnosed simply on the basis of pruritus distribution,
and many of the dermatologic reaction patterns seen in affected cats, such as miliary
dermatitis, eosinophilic granuloma complex and alopecia, seen in cats with flea allergy and
atopy; in some cases, cats may have concomitant allergic conditions. The only way to
definitively diagnose food allergy is to identify a causative food component through a food
elimination trial. However, both palatability and customer compliance can be an issue;
specifically, many owners are unwilling to perform a tease challenge, which is required to
confirm a suspected food allergy. For cats confirmed to have a food allergy, an adequate
maintenance diet should be administered for the rest of the patient's life. (Bryan et al.,
2010)
4 2.1.2 Illustrations
Table 1 – Positive food results
ANIMALS IgE IgG IgA and IgM
Canine 1 - pruritus and chronic diarrhea 4% 4% 23%
Canine 2 - chronic diarrhea 3% 0% 28%
Canine 3 - alopecia, intense pruritus and
diarrhea
2% 0% 18%
Canine 4 - epilepsy 3% 6% 27%
Feline - vomiting, conjunctivitis, sneezing and
alopecia
3% 0% 34%
Table 2 – Positive Foods for IgA and IgM Hypersensitivity
ANIMALS IgA and IgM
Canine 1 - pruritus and chronic diarrhea Pork, lamb, fleitán, duck, turkey, beef, ants, corn
and olive oil
Canine 2 - chronic diarrhea Duck, turkey, lamb, rabbit, sardines, chicken,
duck egg, peas, honey, salmon, mackerel fish,
crustaceans, peanuts, sweet potatoes, white rice,
sunflower oil, olive oil, rosemary
Canine 3 - alopecia, intense pruritus and diarrhea Beef, chicken, duck, turkey, lamb, goat's milk,
halibut fish, salmon, mackerel fish, sardines,
crustaceans, pork, rabbit, corn, white rice, sweet
potatoes, rosemary
Canine 4 - epilepsy Chicken, beef, duck, turkey, rabbit, mackerel
fish, fletán fish, salmon, whey, goat's milk,
yogurt, rice, rice bran, squash, zucchini,
cucumber, peas, chickpeas, oats, corn
Feline - vomiting, conjunctivitis, sneezing and
alopecia
Anchovy, pork, turkey, chicken, rabbit, venison,
goat's milk, cheese, butter, apple, blueberry,
raspberry, strawberry, watermelon, pineapple,
eggplant, beetroot, brussel sprouts, cabbage,
radish, spinach, honey, ginger, coconut, cashew
nuts, mustard
Table 3 – Positive foods for IgE and IgG
ANIMALS IgE IgG
Canine 1 - pruritus and chronic diarrhea Turkey, beef, carrot and
peas
Turkey, beef, lamb,
chicken, venison
Canine 2 - chronic diarrhea Beef, lamb and milk
Canine 3 - alopecia, intense pruritus and diarrhea Beef and milk
Canine 4 - epilepsy Beef, cow's milk, oats,
rice and egg yolk
Lamb, turkey, venison,
corn, potatoes and oats
Feline - vomiting, conjunctivitis, sneezing and
alopecia
Beef, lamb and milk
Table 4 – IgE environmental allergens
ANIMALS IgE
Canine 1 - pruritus and chronic diarrhea Cynodon dactylon, Ciprés ( Cupressus
sempervirens )
Canine 2 - chronic diarrhea
Canine 3 - alopecia, intense pruritus and diarrhea Fungus, Mold (Chaetomium Globosum), Tobacco
Canine 4 - epilepsy Pheleum pratense, Lolium perenne, Cynodon
dactylon, Dermatophagoides farinae
Feline - vomiting, conjunctivitis, sneezing and
alopecia
Apple Tree,
Clover (Triofoliumspp.),
European beech,
Fireweed/Great willow herb
(Epilobiumangustifolium), Hawthorn (Crataegus
spp.), Lilac (Syringa vulgaris), Mangrove,
Mosquito, Orchard grass (Dactylis glomerata) ,
Primrose (Primulus), Privet (Ligustrumspp.)
Table 5 – Prescribed diets
Canine 1 - pruritus and chronic diarrhea. Raw commercial diet with bones with added
homemade ingredients
Canine 2 - chronic diarrhea. Homemade diet cooked with viscera
Canine 3 - alopecia, intense pruritus and diarrhea. Homemade diet cooked without viscera
Canine 4 – epilepsy. Homemade diet cooked without viscera
Feline - vomiting, conjunctivitis, sneezing and alopecia. Complete commercial wet food
3 RESULTS AND DISCUSSION
After eliminating food allergens from the diet, the results were:
Canine 1 – Complete remission of diarrhea and partial, however, almost total
decrease in pruritus. On the other hand, the results of the hypersensitivity tests of this
animal were also positive for environmental allergens.
Canine 2 - Complete remission of diarrhea.
Canine 3 - Complete remission of diarrhea and partial decrease in pruritus and
alopecia. On the other hand, the results of the hypersensitivity tests of this animal were
also positive for environmental allergens.
Canine 4 - Partial remission of epileptic episodes: Lower frequency and intensity,
also increase in the interval between seizures. On the other hand, the results of the
hypersensitivity tests of this animal were also positive for environmental allergens.
Feline - Complete remission of vomiting, conjunctivitis, respiratory condition and
alopecia. On the other hand, the results of the hypersensitivity tests of this animal were
also positive for environmental allergens.
In general, patients who achieved partial remission of symptoms also had an
exacerbated response to specific immunoglobulins for environmental allergens, with total
remission of symptoms being possible in cases of exclusively food hypersensitivity.
And carrying out only one type of examination for food hypersensitivity, such as the
blood test with IgG and IgE without including IgA and IgM, would not be the most reliable
and adequate diagnostic method as it does not analyze all the immunoglobulins involved
in the hypersensitivity process. The most efficient would be to perform both tests together.
4 FINAL CONSIDERATIONS
At the end of the case study work, it is considered opportune to use laboratory tests
to detect food hypersensitivity.
However, it can be considered that the elimination diet would not be the only way to
detect hypersensitivity.
However, it can also be concluded that both diagnostic methods are valid since in
many cases the owner does not have the economic resources to carry out specific
laboratory tests.
REFERENCES
A Verlinden, M Hesta,S Millet y G P J Janssens. Food allergy in dogs and cats: a review.
https://pubmed.ncbi.nlm.nih.gov/16527756/
J Wills e R Harvey. Diagnosis and management of food allergy and intolerance in dogs
and cats. https://pubmed.ncbi.nlm.nih.gov/7848179/
Jacqueline Bryan e Linda A Frank. Food allergy in the cat: a diagnosis by elimination.
https://pubmed.ncbi.nlm.nih.gov/20974403/