Cutaneous adverse food reactions in the canine patient

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1 Cutaneous adverse food reactions in the canine patient D R. M I C H A E L A. R O S S I, D V M, M N S D I P. A M E R I C A N C O L L E G E O F V E T E R I N A R Y D E R M A T O L O G Y C O A S T A L V E T E R I N A R Y D E R M A T O L O G Y & E A R C L I N I C H O U S T O N, T E X A S Canine atopic dermatitis (cad) Inflammatory and pruritic Typical clinical signs Immunoglobulin E (IgE) Multifaceted Genetic Frequent diagnosis cad 1. Age onset <3 years 2. Mostly indoor 3. Corticosteroid-responsive pruritus 4. Chronic or recurrent yeast infections 5. Affected front feet 6. Affected ear pinnae 7. Non-affected ear margin 8. Non-affected dorso-lumbar area 1

2 Nonenvironmental allergens and cad Relationship of nonenvironmental allergens and cad Primarily food Hillier et al. (2001) ACVD Task Force on canine atopic dermatitis Is there a relationship between canine atopic dermatitis and cutaneous adverse food reactions? Nonenvironmental allergens Autoallergens Oral allergy syndrome Food-induced atopic dermatitis (FIAD)/Adverse food reaction (AFR) Autoallergens IgE reactive to selfproteins Perpetuate allergic disease Intracellular proteins May be important in canine patients 2

3 Oral allergy syndrome Environmental allergens are ingested Well described in the human literature Ingestion of cross-reacting allergens Fujimura et al. (2002) Oral allergy syndrome induced by tomato in a dog with Japanese cedar pollinosis Marsella et al. (2010) Environmental and oral challenge with storage mites in beagles experimentally sensitized to house dust mites FIAD/AFR Food can trigger clinical cad lesions Canine AD sensu lato Indistinguishable from environmental disease Pruritus (glucocorticoid responsive) Distal limbs, face, ventrum, pinnae Young age of onset Pruritus of facial mucous membranes May have signs not typical of environmental Poor response to glucocorticoids Perianal pruritus Atypical age of onset GI issues AFR.simplified!? Common cause of nonseasonal pruritus due to immunological and nonimmunological reactions Recent study with 259 dogs 70.7% aeroallergen-induced 25.1% food-induced 4.2% combination 3

4 AFR causes Normal individuals have oral tolerance to dietary proteins Failure of body to develop oral tolerance leads to development of AFR Leaky gut theory Dysfunction that leads to production of inflammation in the body 4

5 AFR clinical signs Clinical signs can mimic aeroallergen-induced atopic disease Breed, sex, or age predilection Labradors, miniature schnauzers, poodles, wheaten terriers, dalmations 33-50% < 1 year of age No pathognomonic clinical signs for AFR AFR clinical signs Primary lesions Papules, macules, erythema, wheals, plaques Secondary lesions Due to pruritus and self trauma Ulcerations, excoriations, alopecia May have only one area affected or multiple areas Secondary infections are common AFR clinical signs Systemic signs GI disturbance in 10-15% of affected individuals Vomiting Diarrhea Increased bowel movements Increased flatulence Tenesmus Fecal mucus and blood 5

6 Diagnosing AFR Difficult and frustrating for owners! Long list of differentials Gold standard 8-12 week elimination diet Provocative exposure testing Why so long?!? Rosser EJ (1993) - Diagnosis of food allergies in dogs 1-3 weeks for 13 dogs 4-6 weeks for 25 dogs 7-8 weeks for 10 dogs 9-10 weeks for 3 dogs Diagnosing AFR Can we use laboratory tests to diagnose food allergies? No alternatives to food trials has yet been found Hardy et al. (2014), Favrot et al. (2017), Mueller et al. (1998) Extremely poor correlation with clinical presentation and dietary testing in small animals Diagnosing AFR Pay attention to dietary history when prescribing diet trial Novel is key! Commercially prepared hypoallergenic diets Home-cooked diets can be very beneficial None of the diets are 100% effective 6

7 Examples of limited ingredient diets Diagnosing AFR Hydrolyzed diets Theory : the protein is made hypoallergenic Problem: not all dogs suffer from type I hypersensitivity Persistent allergenicity is the main problem Olivry et al. (2010) Systematic review of all published articles related to hydrolyzed protein diets up to 50% of dogs with CAFR enrolled in three controlled studies exhibited increases in clinical signs Opinion: Avoid hydrolyzed diets when possible Managing AFR Do we leave patients on novel protein diets long-term? Diet challenges Old, maintenance diet challenge Individual ingredient challenges Probiotics can be very useful in some patients Heart worm and flea preventatives? 7

8 Managing AFR Avoid offending allergens Balanced diet is important! Use antiprurituc and antimicrobial therapy when relapses occur May or may not be glucocorticoid responsive May respond to Atopica, but poor choice Apoquel may be beneficial Cytopoint may also be a poor choice Summary AFR is a relatively common cause of nonseasonal pruritus in canine patients Good data supporting a specific immunological basis for the disease is lacking Proteins are the most likely culprits Novel protein diet trial of appropriate length Control acute flares and secondary infections There will be bumps in the road! References Bexley J, Nuttall T, et al. Co-sensitization and cross-reactivity between related and unrelated food allergens in dogs a serological study. Vet Dermatol 2017; 28: 31-e7. Olivry T, Bizikova P. A systematic review of the evidence of reduced allergenicity and clinical benefit of food hydrolysates in dogs with cutaneous adverse food reactions. Vet Dermatol 2010; 21: Favrot C, Linek M, et al. Western blot analysis of sera from dogs with suspected food allergy. Vet Dermatol 2017; 28: 189-e42. Miller W Jr, Griffin C, Campbell K: Muller and Kirk s Small Animal Dermatology, ed 7, St. Louis, 2013, Elsevier. Hardy JI, Hendricks A, et al. Food-specific IgE and IgG reactivity in dogs with and without skin disease : lack of correlation between laboratories. Vet Dermatol 25: 447-e70. 8