Diet and Dermatology. Glen Burkett BVSc. Diplomate ACVD

Transcription

1 Diet and Dermatology Glen Burkett BVSc. Diplomate ACVD

2 Diet and Dermatology Adverse Food Reaction (AFR) Therapeutic effects of diet Deficiencies or imbalances

3 Adverse Food Reaction (AFR) Non-immunological food toxicity, food poisoning, food idiosyncrasy, pharmacological and metabolic food reactions Immunological Food allergy, food anaphylaxis

4 Food Allergy

5 Food Allergy Typical properties of a food allergen glycoproteins; small molecular weight, generally kilodaltons (kda); water soluble; resistance to heat and digestion. Common food allergens in people: milk, egg, wheat, soy, peanuts, tree nuts, fish, and crustacea

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7 Food Allergy Typically type 1 hypersensitivity (IgE mediated) reactions to proteins larger than 10 kda Incidence:15-35% of allergic dogs; 15% of allergic cats Onset typically in young animals Most animals have not had a recent diet change Non seasonal

8 Food Allergy Clinical signs Clinically indistinguishable from atopic dermatitis Pruritus Erythema Often involving ears, paws, face, perianal, inguinal and axillary areas Recurrent pyoderma

9 Food Allergy Clinical signs: Bilateral otitis may be only sign in 25% of cases Concurrent GI signs in 10-15% of cases Concurrent FAD or AD in 20-30% of cases

10 Food Allergy Diagnosis: Blood test (IgE or IgG) NOT ACCURATE Hair and Saliva tests NOT ACCURATE Skin test NOT ACCURATE

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14 Food Allergy Diagnosis: Elimination diet Home cooked Hydrolyzed Novel protein

15 Food Allergy Home cooked (adult dogs) Single protein + carbohydrate Rabbit, ostrich, kangaroo, venison, alligator, pinto beans, chick peas, lentils, fish Potatoes, sweet potatoes, rutabagas, oats, quinoa 1 part protein: 1-2 parts carbohydrate (by weight)

16 Hydrolyzed diets Food Allergy

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18 Food Allergy Hydrolyzed diets: Soy: Poultry: Royal Canin HP (dry and canned), Purina HA Royal Canin Ultamino(feathers), Hill s Z/D (chicken liver) Royal Canin HP (canned) Salmon: Blue Buffalo HF

19 Food Allergy Problems with hydrolyzed diets Some proteins may not be completely hydrolyzed Some highly sensitive individuals may still react to low molecular weight proteins If adverse food reaction not IgE driven then MW size will have little effect.

20 Food Allergy Novel protein Prescription duck, venison, kangaroo, fish, rabbit OTC novel proteins

21 Food Allergy Problems with commercial novel protein diets Critically appraised topic on adverse food reactions of companion animals (5): discrepancies between ingredients and labeling in commercial pet foods Thierry Olivry and Ralf S. Mueller BMC Veterinary Research :24

22 Food Allergy 17 studies ( ) ELISA or PCR to identify proteins; two studies used mass spectrometry Ingredients that were not on the label in 0 to 83% (median: 45%) of tested diets;

23 Food Allergy Cross reactivity between proteins Beef and cow s milk Chicken and chicken eggs Duck and poultry Venison and beef Lamb and beef All red meats? galactose-alpha-1,3-galactose (alphagal) allergy in people, typically a few months after tick exposure.

24 Ingredients commonly associated with food allergies (dogs) Ingredient Beef, dairy, wheat products Lamb, eggs, chicken, soy Reported cases 69% 25%

25 Ingredients commonly associated with food allergies (cats) Ingredient Beef, dairy, fish Reported cases 80%

26 Food Allergy Important points Dietary trials last 8-12 weeks Watch for and treat secondary infections Okay to use anti-pruritics in the first 4-8 weeks for itch relief Avoid most treats, flavored medications, flavored chew toys, joint supplements etc. during trial

27 Food Allergy Important points Maintain good flea control A response rate >50% but <100% may indicate concurrent environmental allergies. Challenging with the old diet should cause previous symptoms within 2 weeks

28 Therapeutic effects Essential Fatty Acids (EFAs) PUFAs that cannot be synthesized by animals but are required for normal physiological function Linoleic acid (LA) (Omega 6 FA) and alphalinolenic acid (ALA) (Omega 3)are parent EFAs. Cats also require arachidonic acid (AA)

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30 EFAs Many studies involving Omega 3 and 6 FAs Variable results

31 PEA (palmitoylethanolamide) A lipid compound found in most organisms Thought to be produced to down regulate inflammatory responses. Has neuroprotective, anti-inflammatory and analgesic effects Reduces transcription of proinflammatory genes Reduces mast cell activation and degranulation

32 PEA (palmitoylethanolamide) Activates cannabinoid receptors which are involve with inflammation and pain perception. Many studies are looking at effect of PEA in neurodegenerative and inflammatory conditions.

33 PEA Cats with EGC 10/15 showed improvement after 30 10mg/kg BID Dogs with mild/moderate atopy 43/122 (35%) had > 50% reduction of pruritus 73/122 (60%) had > 50% reduction in lesions after 8 weeks 10mg/kg qd.

34 PEA Marketed PEA formulations contain: Unprocessed PEA (frequently referred to as naïve PEA or pure PEA; from 100 μm up to 2,000 μm); Micronized PEA (PEA-m; 2 10 μm range); Ultramicronized PEA (PEA-um; μm range)

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36 Probiotics Live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Can they help the skin?

37 Probiotics Gut- skin axis (gut-brain-skin axis) Microbiome of the gut may influence immune system regulation and inflammation throughout body Microbiome of the gut may also influence the microbiome of the skin. Several studies in mice and humans have shown how probiotic supplements can have an influence on the skin

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39 Probiotics Giving pregnant dogs and their pups probiotics may reduce incidence of atopic dermatitis in the pups later in life. No good studies to show if allergic dogs and cats treated with probiotics will improve. Not enough studies to know what probiotic is beneficial for what condition. Problems with quality of probiotic product.

40 Commercial Diets for skin health Pet food companies may market specialized diets for skin health. Add EFAs, blends of vitamins, minerals, antioxidants, etc. Most studies involving these diets are company driven.

41 Dietary deficiency or imbalance Essential fatty acids Protein Zinc Vitamin A Vitamin D

42 EFAs Important in ceramide production in the skin. Diets low in EFAs may result in pets with dry, dull coat with seborrhea. Sometimes oily unkempt coat.

43 Protein Rare to have a deficiency. Low protein levels involved in the lesions seen with superficial necrolytic dermatitis (SND)

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45 Zinc Syndrome I Malamutes/Huskies defective absorption of zinc Syndrome II Large breed puppies on poor quality diets containing many phytates

46 Vitamin A True deficiency rare. Vitamin A responsive seborrhea, especially Cocker spaniels.

47 Vitamin D Cats and dogs must get Vitamin D from the diet. Classic vitamin D deficiency leads to osteomalacia Low Vitamin D levels has been measured in various diseases in humans. Several studies in dogs and cats show an association with vitamin D levels and various diseases (infections, pancreatitis, CHF, CRF, cancer, IBD)

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49 Vitamin D What is an ideal Vitamin D level? Selting et al (2014) advises optimum level is ng/ml 25(OH)D MSU-DCPAH normal range is ng/ml 25(OH)D. 283 clinically healthy dogs had levels ng/ml 25(OH)D

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51 Vitamin D Can supplementation of Vitamin D help treat/prevent disease?

52 Vitamin D Atopic dermatitis 16 dogs treated with average of 1000IU/kg/day for 8 weeks Pruritus decreased >50% in 9/16 dogs (56%) Lesion scores decreased >50% in 6/16 dogs (37%) No hypercalcemia detected Most dogs <50ng/ml at start; mean increase 80ng/ml

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54 Vitamin D Better response to prednisolone? 20 atopic dogs treated with prednisolone The dogs that started with higher serum 25(OH)D levels had better responses.

55 Vitamin D Use in infections? Vitamin D increases levels of AMP (antimicrobial peptides) in the skin of humans Will supplementation help prevent skin infections?

56 Vitamin D Toxicity Clinical signs of toxicity can be seen at 0.5mg/kg (20,000IU/kg) Merck recommends emesis, activated charcoal and monitoring after 4000IU/kg Signs of acute toxicosis develop within 12 to 36 hours after ingestion Vomiting, diarrhea, anorexia, depression, polyuria and polydipsia. Acute renal failure can occur within 24 to 48 hours. Elevated serum Ca and P

57 Vitamin D Toxicity Toxicity in humans can start at 150ng/ml. Most OTC capsules 200IU -10,000IU each Packet of rat poison (25g) = 720,000 IU

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