Vet360 Vol 4 Issue 3 June 2017 Vet360 - Page 26

NUTRITION
is unknown if this is due to a true dearth of GI signs or if in fact changes in the stool of these dogs were relatively subtle and / or were not noted or volunteered by the owners while obtaining the history . However , a recent report documented 20 dogs with both pruritus and GI signs typical of colitis : fecal mucus , fecal blood , tenesmus and increased fecal frequency . Both cutaneous and GI signs resolved upon feeding the dogs an elimination diet . Lymphocytic-plasmacytic colitis has been linked to food allergy in cats and cheetahs . In one study , having both GI and skin signs increased the likelihood of a diagnosis of food allergy , in a small number of cats .
Neurologic signs such as malaise and seizures rarely have been reported . The author feels that malaise may be under-reported , as an increase in energy level (‘ acting like a puppy , feeling better ’) is often noted upon feeding the dog a diet without the offending allergen ; this may occur before cessation of pruritus . Respiratory signs such as asthma have also been reported , but seem to be quite rare .
Concurrent hypersensitivities have been reported in dogs , and include atopic dermatitis , flea allergy dermatitis , intestinal parasite allergy and even an allergy to bovine insulin . 6 A dog has been reported with a cross reaction between exposure to pollen of Japanese cedar and ingestion of tomatoes . Concurrent pyoderma and / or Malassezia pachydermatis infection is also common . Dogs may have pyoderma ( superficial or deep ) as the only clinical sign of food allergy : These dogs are often clinically normal ( i . e . non-pruritic ) while receiving antibiotics . Therefore it becomes quite important to diagnose and treat secondary infections , as persistence of pruritus due to these infections may confound the ability of the clinician to diagnose the underlying allergy .
Diagnostics
The ideal method of diagnosis is the feeding of an elimination (“ hypoallergenic ”) diet . The experience of the author and of other researchers has been disappointing in the use of serologic or intradermal skin tests to diagnose food allergy in pets in North America .
The elimination diet ideally contains one protein and one starch . These must be based on previous exposure of the dog to various food stuffs . Important to remember is that dogs who live in households with cats tend to have been exposed to fish , through their consumption of either cat food or cat faeces . At UC Davis we often start dogs with pork and potatoes , although pinto beans and potatoes may also be used . Based on non-exposure , rabbit , duck , and tuna are also options . We have also used ‘ exotic ’ foods like elk when feasible . Other than fresh water , nothing else should be fed to the dog during the elimination diet trial . This means that vitamins and chewing toys must be eliminated , and that flavoured medications ( such as certain ecto / endoparasite preventatives ) should be replaced by other , equally effective non-flavored preparations . Protein-flavoured toothpaste should be replaced by the malt-flavored variety . Because the elimination diet is not a balanced one , owners should be warned that the dog may lose weight , develop a ‘ dull ’ haircoat or scaling , or be hungrier than usual . In cats , we often use pork and tapioca ( the latter made with water rather than milk ).
Because many owners are unable or unwilling to cook for their pet for the time period needed , the dermatology service at UC Davis uses commercially available limited-antigen diets . Another option for animals who already have been fed many foods , or whose dietary history is unknown , is the use of hydrolyzed protein diets , in which the protein source is hydrolyzed to small molecular weights , thus avoiding the body ’ s ‘ immunologic radar ’. Usage of a commercially prepared diet will give an approximately 90 % chance of determining a food allergy ; however , none of these diets will work for all animals , and failure of an animal to improve on such a diet may warrant trying another one , or a home-cooked diet in another trial .
The length of the elimination diet is somewhat controversial , however , our observations have justified a dietary trial of 8 to 12 weeks . Persistence of some pruritus at 12 weeks into the diet trial may indicate the need for continuing the diet , but may also indicate the presence of concurrent hypersensitivities . In cases where antibiotics are given to treat secondary infections , or oral corticosteroids for severe pruritus , the diet must be continued for a minimum of 2 weeks past discontinuation of these treatments , in order to properly judge its efficacy .
Upon resolution of clinical signs with the feeding of an elimination diet , the animal should be challenged with its regular diet to confirm the diagnosis of a food allergy . Recurrence of clinical signs is usually noted within two weeks . At that point the animal is given its elimination diet again , and the owner may then elect to challenge with suspected allergens , each allergen being given one to two weeks at a time . The most common proven allergens in the dog are beef , chicken , milk , eggs , corn , wheat , and soy ; in the cat , fish , beef , milk and milk products . Allergies to more than 2 allergens are uncommon . Once the offending allergens are identified , commercially prepared dog foods that do not contain them may be fed to the dog . In cases in which the owners refuse to do provocative testing , one of the limited antigen pet foods may be used as a maintenance diet .
ZINC-RESPONSIVE DERMATOSIS
Zinc-responsive dermatosis consists of two syndromes . Syndrome I has been identified in Siberian huskies and occasionally other breeds and is typified by crusting and scaling of the mucocutaneous junctions , elbows and foot pads . These dogs are thought vet360
Issue 03 | JUNE 2017 | 26
NUTRITION is unknown if this is due to a true dearth of GI signs or if in fact changes in the stool of these dogs were relatively subtle and/or were not noted or volunteered by the owners while obtaining the history. However, a recent report documented 20 dogs with both pruritus and GI signs typical of colitis: fecal mucus, fecal blood, tenesmus and increased fecal frequency. Both cuta- neous and GI signs resolved upon feeding the dogs an elimination diet. Lymphocytic-plasmacytic colitis has been linked to food allergy in cats and cheetahs. In one study, having both GI and skin signs increased the likelihood of a diagnosis of food allergy, in a small number of cats. Neurologic signs such as malaise and seizures rare- ly have been reported. The author feels that malaise may be under-reported, as an increase in energy lev- el (‘acting like a puppy, feeling better’) is often noted upon feeding the dog a diet without the offending al- lergen; this may occur before cessation of pruritus. Respiratory signs such as asthma have also been re- ported, but seem to be quite rare. Concurrent hypersensitivities have been reported in dogs, and include atopic dermatitis, flea allergy der- matitis, intestinal parasite allergy and even an allergy to bovine insulin. 6 A dog has been reported with a cross reaction between exposure to pollen of Japa- nese cedar and ingestion of tomatoes. Concurrent pyoderma and/or Malassezia pachydermatis infection is also common. Dogs may have pyoderma (superfi- cial or deep) as the only clinical sign of food allergy: These dogs are often clinically normal (i.e. non-prurit- ic) while receiving antibiotics. Therefore it becomes quite important to diagnose and treat secondary in- fections, as persistence of pruritus due to these in- fections may confound the ability of the clinician to diagnose the underlying allergy. Diagnostics The ideal method of diagnosis is the feeding of an elimination (“hypoallergenic”) diet. The experience of the author and of other researchers has been disap- pointing in the use of serologic or intradermal skin tests to diagnose food allergy in pets in North Amer- ica. The elimination diet ideally contains one protein and one starch. These must be based on previous expo- sure of the dog to various food stuffs. Important to re- member is that dogs who live in households with cats tend to have been exposed to fish, through their con- sumption of either cat food or cat faeces. At UC Davis we often start dogs with pork and potatoes, although pinto beans and potatoes may also be used. Based on non-exposure, rabbit, duck, and tuna are also op- tions. We have also used ‘exotic’ foods like elk when feasible. Other than fresh water, nothing else should be fed to the dog during the elimination diet trial. This means that vitamins and chewing toys must be elimi- nated, and that flavoured medications (such as certain vet360 Issue 03 | JUNE 2017 | 26 ecto/endoparasite preventatives) should be replaced by other, equally effective non-flavored preparations. Protein-flavoured toothpaste should be replaced by the malt-flavored variety. Because the elimination diet is not a balanced one, owners should be warned that the dog may lose weight, develop a ‘dull’ haircoat or scaling, or be hungrier than usual. In cats, we often use pork and tapioca (the latter made with water rath- er than milk). Because many owners are unable or unwilling to cook for their pet for the time period needed, the dermatol- ogy service at UC Davis uses commercially available limited-antigen diets. Another option for animals who already have been fed many foods, or whose dietary history is unknown, is the use of hydrolyzed protein di- ets, in which the protein source is hydrolyzed to small molecular weights, thus avoiding the body’s ‘immu- nologic radar’. Usage of a commercially prepared diet will give an approximately L H[Hو]\Z[[˜H[\N]\ۙHو\HY][ܚ™܈[[[X[[Z[\Hو[[[X[[\ݙBۈXHY]X^H\[Z[[\ۙK܈BYKXYY][[\X[ H[وH[[Z[][ۈY]\Y]]ۋBݙ\X[ ]\\؜\][ۜ]H\YYYHY]\HX[و LYZˈ\\[HوYB\]\] LYZ[HY]X[X^H[X]BHYY܈۝[Z[HY] ]X^H[[KB]HH\[Hوۘ\[\\[]]]Y\ˈ[\\\H[X[X\H][X]Xۙ\B[X[ۜ܈ܘ[ܝX\Y܈]\H\]\HY]]\H۝[YY܈HZ[[][Hو YZœ\\۝[X][ۈو\HX]Y[[ܙ\œ\HYH]YXXK\ۈ\][ۈو[X[Yۜ]HYY[ق[[[Z[][ۈY] H[[X[[H[[Y]]Y[\Y]ۙ\HHXYۛ\وH[\KX\[Hو[X[Yۜ\\X[HY][YZˈ]][H[[X[\][]™[[Z[][ۈY]YZ[[Hۙ\X^H[[X[[H]\XY[\[XX[\[Z[][ۙHYZ]H[YKH[[[ۈݙ[[\[[H\HYYXB[Z[YܛX] [N[H] \ YYZ[[Z[Xˈ[\Y\[ܙH[[\[\H[[[ۋۘHHٙ[[[\B[\HY[YYY [Y\X[H\\Y]۝Z[[HX^HHYHˈ[\\[XHۙ\Y\Hݛ]]B\[ۙHوH[Z]Y[Y[]X^HB\Y\HXZ[[[HY] STTӔUHTPUT–[\\ۜ]H\X]\ۜ\و[BY\ˈ[YHH\Y[Y[YYY[X\X[\Y\[\[ۘ[H\YY[\\YYYHܝ\[[[[وH]X][[\[B[ۜ[[Yˈ\H\HY