FOOD HYPERSENSITIVITY IN A SMALL ANIMALS CLINIC: Laboratory tests as a diagnostic method for detecting allergens.

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

Table 2 – Positive Foods for IgA and IgM Hypersensitivity

Table 3 – Positive foods for IgE and IgG

Table 4 – IgE environmental allergens

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/