Diagnosis and treatment of food allergy in cats (Proceedings)

Article

Previous recommendation of a 3 week elimination diet trial was empirical.

Prospective clinical evaluation of food allergic cats

  • Previous recommendation of a 3 week elimination diet trial was empirical

  • Initial recommendation in this study was to feed a home-cooked restricted diet for 60 days

  • In several instances the results were equivocal after 60 days and the diet was fed an additional 30 days.

Data collected

  • Time elapsed before maximal clinical response on diet

  • Time elapsed before return of initial clinical signs when fed previous diet

  • Age, breed, sex, clinical signs

  • Responsiveness to glucocorticoids

  • Concurrent disease conditions

  • Final treatment diets

Diets Fed

  • Formulated based on known past exposure

  • Avoided any previously consumed foods

  • Consisted of home cooked foods

  • Protein sources - rabbit, venison, lamb, duck, goose, ostrich, emu

  • Carbohydrate source - green peas, rarely rice or potatoes

Results - Time elapsed before maximal clinical response

  • 1-3 weeks - 4 cats

  • 4-6 weeks - 7 cats

  • 7 weeks - 1 cat

  • 9 weeks - 1 cat

  • Recent date – diet trials x 12 weeks

Results - Time elapsed before return of initial clinical signs

  • 15-30 minutes - 2 cats

  • 24 hours - 2 cats

  • 2-3 days - 4 cats

  • 6-8 days - 4 cats

  • 10 days - 1 cat

  • Recent data – feed previous diet x 14 days

Age At Onset of Clinical Signs

  • Range of 3 months to 11 years

  • <1 year old - 3 cats (23%)

  • 1-2 years old - 3 cats (23%)

  • 4 years old - 2 cats (15%)

  • 6-11 years old - 5 cats (39%)

  • Compared to Atopic Dermatitis and Flea Allergy, this is older in general for the development of an allergic skin disease

  • New Record = 12 years of age

 

Breeds Affected

  • Siamese, Domestic Shorthair, Domestic Longhair

Clinical Signs

  • Non-seasonal pruritus

  • Most commonly affects the ear/pinnae, pre-aural region, neck, periorbital region and face

  • Miliary type lesions most common (“Miliary dermatitis”)

  • Eosinophilic plaques, Rodent ulcers

  • Feline symmetrical alopecia

  • Severe excoriations can occur

  • Angioedema, urticaria, conjunctivitis

Response to Glucocorticoids

  • Complete cessation of pruritus - 64% of cases

  • Partial reduction in pruritus - 9% of cases

  • No reduction in pruritus - 27% of cases

Graham-Mize CA, Rosser EJ, Hauptman J: Absorption, bioavailability and activity of prednisone and prednisolone in cats. Adv Vet Derm, vol. 5: 152-158.

  • Greater than a 6-fold difference in Cmax of oral prednisolone (Cmax= 1400 ng/ml) vs. oral prednisone (Cmax= 220 ng/ml)

  • Cmax of oral prednisolone after oral prednisone only 122 ng/ml

  • Results indicate both a decreased gastrointestinal absorption of prednisone compared to prednisolone, and possible decreased conversion of prednisone (inactive form) to prednisolone (active form) by the liver in cats = 12 fold difference

Concurrent Primary Pruritic Skin Diseases

  • Flea Allergy Dermatitis

  • Atopic Dermatitis

  • Flea Allergy and Atopic Dermatitis

  • Flea Collar Hypersensitivity

Diagnosis

  • Treat suspected food allergy cases symptomatically for first 6-12 months before recommending an elimination diet trial

Rationale For Initial Symptomatic Therapy For 6-12 Months

51 food allergic dogs followed for 3 years

  • Only 3 dogs re-developed pruritus

  • 2 dogs became flea allergic

  • 1 dog became atopic

  • None of the dogs became pruritic due to the new hypoallergenic treatment diet

  • All dogs had been eating the initial sensitizing diet for 6-12 months or longer

Dogs Started On Elimination Diet Prior To 6-12 Months Of Pruritus

  • 2 cases initially on beef/soy based diets

  • Placed on lamb based diets after 3 months

  • Pruritus controlled for 2 months

  • Pruritus re-developed and dogs found to be reacting to lamb

 

Dogs Started On Elimination Diet Prior To 6 Months of Pruritus

  • 1 case initially on lamb/rice based diet

  • Placed on venison based diet after 2 months

  • Pruritus controlled for 3 months

  • Pruritus re-developed and dog found to be reacting to venison

Theory of an Immunologic Window

  • Patient is genetically programmed to become sensitized to commonly exposed antigens in the diet after a certain age

  • At this age, sensitization begins over a 6-12 month time period?

  • After this time period of programming, the sensitizing immunologic window closes

Immunology of food allergy

IgE mediated food allergy:

  • Common in children - peaks at 1 yr.

  • Consider skin testing and in-vitro serum testing in kittens?

  • Rare in adults

  • False negative skin tests in adults

Delayed hypersensitivity reactions to foods:

  • More common in adults

  • Consider patch testing with foods

Elimination diet trial – minimum 8-12 weeks in duration

Protein hydrolysate formulated diets:

Reducing the Molecular Weight (Daltons) of a specific protein in the diet

  • Purina Veterinary Diets - HA Formula - Hydrolyzed soy (10,000 Daltons), corn starch, canola/coconut oil – Experimental Trial Diet Only

  • Hill's Prescription Diets

  • Feline z/d Ultra (canned) - Hydrolyzed chicken liver (3,000 Daltons), corn starch, soybean oil

  • Feline z/d Low Allergen(dry) - Hydrolyzed chicken liver, rice, soybean oil

  • Feline Hypoallergenic Treats - Hydrolyzed chicken liver, rice,  soybean oil

  • Royal Canin Veterinary Diet (Waltham)

  • Hypoallergenic HP23 Feline – Hydrolyzed soy (10,000 Daltons), rice, chicken fat, beet pulp, anchovy oil, soya oil

Home-cooked elimination diet trial

  • Restricted diet fed for up to 90 days

  • Formulate based on known past exposure

  • Avoid any previously consumed foods

  • “Nothing else is to pass the cat's lips for the next 60 days”

Discontinue all

  • Table scrapes

  • Cat treats

  • Chewable heartworm preventative

  • Chewable vitamin supplements

  • Essential fatty acid diet supplements

Feline diets

Protein sources

  • Rabbit, lamb, venison, duck

  • Cook by boiling or broiling

Carbohydrate sources

  • Green peas

  • Often refuse rice or potatoes

  • Most often feed protein source alone

Treatment diets - feline

  • Rabbit and rice based canned diets (Nature's Recipe)

  • Venison, duck, or rabbit and green pea based canned and dry diets (d/d canned, Hill's)

  • Lamb and barley based canned diet (Eukanuba Response Formula LB for Cats)

  • Lamb, venison, duck, or rabbit and green pea based canned and dry diets (Royal Canin/Waltham/Innovative Veterinary Diets)

Home cooked treatment diets

Protein source

  • Lamb, venison, rabbit, chicken, turkey, beef, duck, goose, ostrich, emu

Carbohydrate source

  • Green pea, rice, potato or sweet potatoes

Essential fatty acid dietary supplement

  • Derm Caps, EFA-Caps

Dicalcium phosphate

  • Non-flavored, additive free multiple vitamin and mineral supplement

  • Taurine for cats

Balanced home-made elimination diet for cats

  • ½ pound cooked potatoes, rice, or green peas

  • 1 pound cooked lamb, venison, ostrich, emu, rabbit, or duck

  • 1 teaspoon Dicalcium phosphate

  • ½ tablespoon Safflower Oil (Hollywood Brand only)

  • 2 teaspoons light salt

  • 1½ tablets of Nature Made® Multi Max – Complete Multi Vitamin/Mineral Supplement with Iron

  • 350 mg Taurine

Feeding guidelines:

  • Broil, boil, or bake lamb and grind or finely chop.

  • Add salt to cooking water for rice, potatoes, or green peas. Mix the safflower oil, Dicalcium phosphate, vitamin/mineral supplement, and taurine with the rice, potatoes, or green peas, and then add the mixture to the meat puree. Keep refrigerated and warm in microwave to increase palatability.

  • Feed 2½ ounces/5 pounds of cat/day.

Foods associated with exacerbation of clinical signs

  • Any food items being prepared in the kitchen - “The Counter Cat”

  • Meats, cheeses, cooking oils, margarine, breads, odors from various cooked foods

  • Peoples favorite snack foods

  • Popcorn, pretzels, peanuts, cookies (Oreo), potato chips, corn chips, doughnuts, pizza, french fries

New dilemma

  • Many patients with a possible food allergy that have already eaten and been exposed to “everything but the kitchen sink”

  • Possible cross contamination of commercial diets during processing

  • Prescription and non-prescription hypoallergenic diets

  • Patients reacting to various ingredients used in the processing of commercial diets

 

 

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