Adverse reactions to food. Are they worth investigating
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Adverse reactions to food in pets are worth investigating as a potential cause of skin disease. While food allergies represent a small percentage of cases, food trials lasting 4-12 weeks can help diagnose food sensitivities. A true food allergy is immune-mediated and requires identifying and removing the offending allergen from the pet's diet long term through use of hydrolyzed protein diets or homemade recipes. Other potential contributing factors like infections, parasites, and environmental allergens should also be addressed. The webinar discusses guidelines for properly conducting food trials and alternative diagnostic tests to confirm food allergies in pets.
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Adverse reactions to food. Are they worth investigating
- 1. Adverse Food Reactions- are they worth investigating? Anthony Chadwick BVSc CertVD MRCVS The Webinar Vet
- 2. In my Liverpool home
- 3. • Qualified in 1990 • CertVD in 1995 • Set up The Webinar Vet in 2010 • Sold first opinion practice in 2011
- 4. The Story of Rosie McCartney
- 5. The Take Home Messages • Food Allergy/Intolerance is an important cause of skin disease in dogs and cats • Food Trials are difficult to do well • There are often other components contributing to the itch
- 6. Outline of Talk • Some definitions • Aetiology and Pathogenesis • Clinical Signs • Diagnosis • Treatment
- 7. Definitions • Adverse reaction to food • Food allergy reactions • Food intolerance reactions
- 8. Atopic dermatitis and food allergy in humans • Numerous studies show a clear relationship between food allergens and the development of AD • Often food allergy seen in infants and young children • Just under 40% of AD cases will have concurrent food allergy
- 9. Aetiology and Pathogenesis • Not fully elucidated in dogs • A subset have an IgE mediated food allergy • Also type III and IV • However vast majority no immunological cause found
- 10. Aetiopathogenesis • Puppies who have a poor start to life • Intestines damaged by virus or worms. Protein allergens can gain access systemically • Histamine releasing factors continue to be active long after offending allergen removed • In older dogs sensitisation to an antigen may follow a long refractory period of upto 2 years before clinical signs are present
- 11. • In 80% of cases only 1-2 allergens involved • Common allergens include: beef, soya, chicken, milk, corn, lamb, wheat, eggs and lamb
- 12. How long should you perform a food trial for • 7 days • 21 days • 28 days • 42 days • 84 days
- 13. What % of your allergic pets have a food component • Less than 5% • 5-10% • 10-15% • 15-20% • More than 20%
- 14. How common is Adverse Reaction to Food • 30% Chamberlain • 3% Kunkle • 2% Carlotti • 13% Saridomichelakis • 23% Jackson
- 15. Clinical Signs • Food allergy can develop at any age • I see 2 subsets: very young and 7 plus • Labradors predisposed • Abyssinians also
- 16. Clinical signs 2 • Non seasonal pruritus • Recurrent pyoderma • Similar distribution to atopy • angioedema • Otitis • Concurrent GI signs
- 19. Clinical signs in cats • Miliary dermatitis • Symmetrical alopecia • Head and neck pruritus • Eosinophilic granuloma complex • Concurrent GI signs in about 30% of cats
- 23. Food Trialling • 4-12 weeks required • Home prepared • Unusual protein source • Hydrolysate • All non seasonal pruritus should be food trialled
- 24. Hydrolysed Proteins Mast cell degranulation Allergenic protein Histamin e IgE Sensitised mast cell Polypeptides (HYDROLYSATES) Intact protein Enzymatic hydrolysis
- 25. Hydrolysed Proteins Mast cell degranulation Hydrolyse d proteins No crosslinking – no degranulation
- 26. 26 © Royal Canin SAS 2012. All Rights Reserved. Extreme hydrolysation: • Low molecular weight feather hydrolysate • In an overall diet analysis, 95% of the diet is less than 1kDa EXTREME HYDROLYSIS Independent analysis of final product
- 27. Alternative tests • Intestinal permeability • Gastric provocation • Colonoscopy provocative test • Intradermal skin test • Patch test • Serum IgE testing
- 28. Food Challenging • Feed all old diet back again • Response usually rapid but upto 3 weeks reported • Then individual ingredients • Dairy relapse in 4 days, cereal 8 days(Harvey)
- 29. Treat other clinical signs • Malassezia • Pyoderma • Otitis
- 30. How much allergen is too much? • Jackson’s beagle colony reacted to 1g of corn • Some animals may be less sensitive
- 31. Are the diets sufficient for lifelong use? • Anallergenic • Hypoallergenic • Home prepared diet
- 32. My plan for non-seasonal pruritus • Treat infections • Food and flea trial • See back in 4 weeks • Continue food trial if some improvement, possibly skin test • Food challenge at 8 weeks • If positive try individual allergens
- 33. Vets South offer • All my topics on slide share and access at The Webinar Vet • £1 membership offer • Access to pet webinars
- 34. Upcoming webinars • Sub plexus flaps • Cushings disease- The American Perspective • Glaucoma • Equine series • 400 hours of archive
- 36. Any Questions?
- 37. 10% of sales going to gorilla conservation • Bwindi Impenetrable Forest 2005 • #gorillachallenge
Editor's Notes
- Inflammatory mediators Cytokines chemokines