In this issue:

Proper Nutrition for Healthy Skin:Suboptimal nutrition may predis-pose a pet to dry skin, fragile hairfibers or increased susceptibilityto dermatoses. Are supplementsthe answer? Page 1

Dry Skin:Optimal hydration of the stratumcorneum, an important factoraffecting skin health, is influencedby environmental factors. Page 1

Food Allergy:Fecal IgE may become thediagnostic criteria for dogswith suspected food allergy.Page 5

Client Compliance:How well do clients followinstructions?Page 6

PurinaResearchReport

A Research Updatefor the Veterinarian from the

Ralston Purina CompanySt. Louis, Mo., USA

®

The stratum corneum plays a piv-otal role in preventing excessivewater loss from thebody.1,2 The extra-cellular space of thestratum corneumcontains glycolipidsand glycosaminogly-cans as well as severalimmunologicallyimportant substances.The glycolipids appearto be critical in support-ing the water barrierfunction of the stratumcorneum. Water

diffuses out from the body and islost at the skin surface. This waterloss is referred to as transepider-mal water loss (TEWL) and is driven by the steep concentration

gradient between the hydrat-ed internal body tissues

with a moisture contentof approximately 75%and the drier external

atmosphere.1,3

Normal skin contains10 to 40% water,with about 35%water in the stratum

corneum considered optimal.3

Moisture content in canine skindepends on anatomic location,with ear pinna, chest and groinskin having the highest moisturelevels.4 Low skin hydration isassociated with increased TEWLand reduced skin surface lipidcontent. Such changes are char-acteristic of defective epidermalbarrier function and typical ofatopic dermatitis and variousscaly dermatoses.5,6,7 Atopic dogsalso show abnormal water-absorptive (hygroscopic) andwater-holding capacity.4

®

Healthy Skinand HaircoatThe Importanceof Nutrition

A pet’s skin and haircoat are among the most visible signsof health and vitality. The skin and haircoat are of vitalimportance to the body’s protective mechanisms againstenvironmental insults of all kinds, from infectious agents totemperature gradients.1 In addition, hair is of great aestheticimportance to owners and a source of great concern whenit is not normal.2

D. P. Laflamme, DVM, PhD, DACVN

Maintaining Skin Hydrationcontinued on page 2

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continued on page 2

2

Nutritional deficiencies of many typesmay be manifested by alterations in thishighly visible organ system. Perhapsbecause of these issues, nutritional sup-plements and nutraceuticals are widelyused in skin and hair care.

Good nutrition is essential to normal skinhealth. Normal keratinization requires anadequate supply of several nutrients,including protein, fatty acids, zinc, copper,vitamin A and B vitamins.1 Deficienciesin numerous essential amino acids, fattyacids, vitamins or minerals can causevarious deviations in skin structure orfunction. Epidermal atrophy occurswith protein, calorie and vitamindeficiencies. Hyperkeratosis oracanthosis can occur with mag-nesium, zinc, pantothenicacid, pyridoxine, biotin, vitamin A or essential fatty acid deficiencies,while parakeratosis issymptomatic of zincdeficiency. Pigmentchanges may beseen with deficien-cies of copper,

cysteine or panthothenic acid. Alopecia orchanges in the sebaceous glands mayoccur with zinc, biotin or riboflavin defi-ciencies. In addition to these directeffects, suboptimal nutrition may increasesusceptibility to parasites, such as mangemites, fleas and lice, as well as enhancesusceptibility to skin infections.3,4,5

Providing minimum nutrient requirements,by definition, should eliminate all derma-tologic signs associated with dietary

deficiencies. However, certainanimals may have genetic ormetabolic differences thatmay respond to intakesgreater than are consideredadequate to avoid recognized

dietary deficiencies. In addi-tion, most pet owners do notexclusively feed complete andbalanced pet foods.6,7 Excessivetreats or nutritional imbal-anced supplements can

contribute to nutritionalimbalances. Thus, an

assessment of a pet stotal diet may reveal

areas that could benefit from nutritionalmodifications.

ProteinSkin contains a significant amount ofprotein and serves as a major source of protein reserves when intake is inade-quate.8 The hairshaft is composed primari-ly of alpha-keratin protein. Specific skineffects from gross protein deficiencyinclude hyperkeratosis, epidermal hyperpigmentation, flaky skin, loss of hairpigmentation, and increased hair fragility.4,9

This may be seen as crusty skin lesionswith patchy alopecia and dry, brittle hair-coats. Microscopic changes include puff-ing and flaking of the keratin layer andfoamy-looking collagen layers.4 Hair rootchanges occur in protein malnutrition,with an increased number of follicles intelogen phase and a decreased number inanagen phase.10 Subclinical protein defi-ciency may be less noticeable. Sub-optimal protein intake can decrease hairor wool production and decrease fiberdiameter, length and breaking strength.3,11,12

Increasing dietary protein or sulfur aminoacid intake increased the rate of divisionof cells in the follicle bulb matrix, whichincreased keratin gene expression, proteindeposition and follicle growth rate.3,13

Optimum dietary protein for dogs, basedon measures of protein turnover in muscleand liver, appears to be at least 20% ofcalories from high-quality protein.8 Even

Optimal hydration of the stratumcorneum is the single mostimportant factor influencingmicrofloral growth at the skin sur-face.8 Moisture moving outwardthrough the skin hydrates thecells prior to being evaporatedinto the atmosphere. Dry skin ischaracterized by a lack of moisturein the keratinized stratum corneum.Disturbances in keratinization orother disorders in the stratumcorneum may increase its perme-ability, allowing either increasedwater loss or over-hydration. An

over-moist stratum corneum is aless efficient barrier while anabnormally dry stratum corneumbecomes brittle and inflexible,resulting in painful fissures aswell as breaks in the physicalbarrier of protection.3

Some environmental factors thathave been shown to affect skinhydration and TEWL include diet,bathing, soaps, shampoos andmoisturizers.7,9,10,11 Dietary alter-ations of protein, amino acids andlipids may influence hydrationand moisture kinetics. A deficien-cy of protein or essential aminoacids can lead to dry skin, amongother changes. Adequate dietary

fat and omega-6 fatty acids arecritical to normal skin hydration.The role of omega-3 fatty acids inTEWL remains undefined. Onestudy suggested a beneficialeffect when flaxseed oil wasadded to the diet.10 On the otherhand, a recent study found nochanges in TEWL or other indicesof skin and haircoat conditionover a range of dietary omega-6:omega-3 fatty acid ratios.12 Variousshampoos and humectants haddiffering effects on TEWL and skinhydration. Of several productstested, Hylyt (DVM Pharmaceuticals),Sesame Oil Rinse (VeterinaryPrescriptions) and Alpha Keri(Bristol-Meyers Squibb Co.) were

Suboptimal protein intake can

decrease hair diameter, length

and breaking strength.

Healthy Skinand Haircoatcontinued from page 1

MaintainingSkin Hydrationcontinued from page 1

3

greater quantities may be beneficial forenhanced haircoat quality.

Fat and Fatty AcidsGeneralized flaky desquamation, coarse,lusterless haircoats or alopecia, and pruri-tus are among the changes seen withessential fatty acid deficiency. Essentialfatty acids may be oxidized and denaturedin poor quality foods, foods stored too longor at high temperatures, or those inade-quately preserved with antioxidants.Animals fed these foods may show evi-dence of essential fatty acid deficiency.Such signs also may be observed in petsfed low-fat diets over extended periods,pets with fat malabsorption syndromes, orthose with unusually high requirementsfor these nutrients. Numerous fatty acidsupplements are available; however,response to fatty acid supplements inopen clinical trials has been highly vari-able.14 Pet health and overall diet qualityshould be addressed to identify underlyingproblems prior to administeringsupplements.

VitaminsRiboflavin deficiency can cause a dryflaky dermatitis with reddening of theskin and hair loss. Biotin deficiency cancause the hair to become thin or lose pig-ment and the skin to become dry andflaky or greasy.4 Pantothenic acid defi-ciency can lead to loss of hair pigment

and hair loss. Such deficiencies ofB-vitamins are rare among petsfed quality commercial pet foods.However, since table scraps,treats and other foods can makeup a large portion of the diet formany pets, deficiencies should beconsidered if these signs areobserved. Various forms ofvitamin supplements are avail-able. Most contain all theB-vitamins so it is not necessary to identify the specific deficiency.

Vitamin A deficiency can appear like anessential fatty acid deficiency and lead todry, scaly skin.4 Excessive vitamin A alsocauses skin lesions that appear similar to

those of vitamin A deficiency, includingdry skin, alopecia and pruritus. On theother hand, vitamin A or related com-pounds have been used topically to treatvarious skin problems in humans.Retinoic acid (a form of vitamin A) hasbeen shown to be involved in regulationof epidermal keratinocytes by regulating

gene transcription.15 Dietary supplementa-tion with vitamin A has been used to treatseborrhea in American cocker spanielswhile topical treatments have been usedfor a number of skin conditions in variousbreeds.16 The vitamin A supplement, givenat 10 to 25 times the requirement of 100IU/kg body weight/day, appeared mostuseful in patients with marked follicularplugging and hyperkeratosis.14

Active vitamin D (1,25-dihydroxychole-calciferol) has been investigated in humanmedicine as a treatment for psoriasis andichthyosis, both hyperproliferative condi-tions.17 Cells of the outer root sheath andepidermal cells have vitamin D receptors.In vitro data shows that active vitamin Dinhibits the proliferation of keratinocytesand dermal fibroblasts. Vitamin D supplements (2 ug/day orally) were beneficial in human patients with psoriasis. Active vitamin D itself canbe toxic, so safety as well as efficacy must

the most effective in decreasingTEWL, while Humilac (Allerderm-Virbac) was most effective atincreasing the hydration of thestratum corneum.9

REFERENCES

1. Chesney CJ. Water: Its Form, Functionand Importance in the Skin of DomesticAnimals. J Sm Anim Pract. 1993;34:65-71.

2. Hattingh J. The Relationship betweenSkin Structure and TransepidermalWater Loss. Comp Biochem Physiol.1973;45:685-688.

3. Marks R. The Skin as an Organ ofProtection In Soter NA, Baden HP.Pathophysiology of DermatologicDiseases, 2nd ed. McGraw-Hill, NewYork. 1991;57-65.

4. Chesney CJ. Measurement of SkinHydration in Normal Dogs and in Dogs

with Atopy or a Scaling Dermatosis. JSm Anim Pract. 1995;36:305-309.

5. Berardesca E, Fideli D, Borroni G, et al.In Vivo Hydration and Water-RetentionCapacity of Stratum Corneum inClinically Uninvolved Skin in Atopicand Psoriatic Patients. Acta DermVenereol (Stockh). 1990;70:400-404.

6. Linde YW. Dry Skin in AtopicDermatitis. Acta Derm Venereol(Stockh). 1992: Suppl 177:9-13.

7. Thune P, Nilsen T, Hanstad IK, et al. TheWater Barrier Function of the Skin inRelation to the Water Content ofStratum Corneum, pH and Skin Lipids.Acta Derm Venereol (Stockh).1988;68:277-283.

8. Muller GH, Kirk RW, Scott DW. SmallAnimal Dermatology, 4th ed. W. B.Saunders, Philadelphia. 1989;1-48.

9. Campbell KL. Effect of Four TopicalHumectant/Emollient Solutions on theSkin of Dogs. Proc 12th AnnualMembers’ Meeting AAVD & ACVD. Las

Vegas, NV. 1996;49-50. 10. Campbell KL, Roudebush P. Effect of

Four Diets on Serum and CutaneousFatty Acids, Transepidermal WaterLosses, Skin Surface Lipids, Hydrationand Condition of the Skin and Haircoatof Dogs. Proc 11th Annual Members’Meeting AAVD & ACVD. Santa Fe, NM.,1995;80-81.

11. Stender IM, Blichmann C, Serup J.Effects of Oil and Water Baths on theHydration State of the Epidermis. ClinExp Dermatol. 1990;15:206-209.

12. Campbell KL, Laflamme DP, Harrison J.Effect of Four Diets with VaryingOmega 6: Omega 3 Ratios on theHealth and Appearance of the Skin andHaircoat in Normal Dogs. Proc 4thWorld Congress of VeterinaryDermatology. San Francisco, CA. 2000.

Since table scraps, treats andother foods can make up a largeportion of the diet for many pets,

deficiencies should be considered.

4

be considered.

MineralsZinc is critical for normal skin develop-ment, and deficiency leads to parakerato-sis and dermatitis. Zinc-responsive der-matitis generally is reported in puppies orzinc-sensitive breeds (primarily SiberianHuskies and Alaskan Malamutes),

although it can occur in other breeds. Asimilar condition reported in dogs fedgeneric or low-cost commercial dog foodswas presumed to be zinc deficiency sec-ondary to poor zinc bioavailability.18,20

Some older dogs with poor haircoats andscaly skin also may improve with zincsupplementation.19 Zinc bioavailabilitycan be influenced by the zinc source, aswell as by dietary phytate, supplementalcalcium and other variables. Affecteddogs have scaling, crusting skin lesions,hyperkeratosis and secondary skin infec-tions that respond to dietary change orzinc supplementation. Elemental zinc(initial dose 1mg/kg/day, divided and

given with food) from either zinc sulfateor zinc gluconate has been recommendedas an initial dose for dogs with suspectedzinc-responsive dermatosis.16 The dosemay need to be increased for some dogs,and should be reduced following resolu-tion of signs.

REFERENCES

1. Muller GH, Kirk RW, Scott DW. Small AnimalDermatology, 4th ed. W. B. Saunders,Philadelphia. 1989;1-48.

2. Scott DW. The Biology of Hair Growth and itsDisturbances. In vonTscharner C, HalliwellREW. Advances in Veterinary Dermatology.Bailliere Tindall, London. 1991;3-33.

3. Galbraith H. Nutritional and HormonalRegulation of Hair Follicle Growth andDevelopment. Proc Nutr Soc. 1998;57:195-205.

4. Mosier JE. Relationships of Nutrition and SkinProblems. Mod Vet Pract. 1978;59:105-109.

5. Rahaman SA, Yathiraj S. Commercial vsTraditional Food in Canine Health. Proc. PurinaNutrition Forum, St. Louis, MO. 1999;179.

6. Donoghue S, Khoo L, Glickman LT, KronfeldDS. Body Condition and Diet of RelativelyHealthy Older Dogs. J Nutr. 1991;121:S58-59.

7. Jackson MW, Laflamme DP. Behavioral Aspectsof Canine Weight Management: Understandingthe Dog-Owner Relationship. EffectiveManagement of Canine Obesity. Ralston PurinaCompany. 2000;5-7.

8. Allison JB, Wannemacher RW. The Concept andSignificance of Labile and Over-all ProteinReserves of the Body. Am J Clin Nutr.1965;16:445-452.

9. Latham MC. The Dermatosis of Kwashiorkor inYoung Children. Seminars Derm. 1991;10:270-272.

10. McLaren DS. Skin in Protein EnergyMalnutrition. Arch Dermatol. 1987;123:1674-1676a.

11. Sahlu T, Fernandez JM. Effect of IntraperitonealAdministration of Lysine and Methionine onMohair Yield and Quality in Angora Goats. JAnim Sci. 1992;70:3188-3193.

12. Shimoshima C, Nishioka C, Hakiyama K, et al.Influences of Protein Malnutrition on AminoAcid Composition, Trace Mineral Elements andTensile Strength of Rat Hairs. J Nutr SciVitaminol. 1988;34:67-78.

13. Matheson HB, Westgate GE, Parmar PP, et al.Nutrition and Metabolism in Isolated HumanHair Follicles. Exp Dermatol. 1999;8:319-320.

14. Codner EC, Thatcher CD. NutritionalManagement of Skin Disease. Compendium.1993;15;411-423.

15. Volberg TM, Nervi C, George MD, Fujimoto W,Krust A, Jetten AM. Retinoic Acid Receptors asRegulators of Human Epidermal KeratinocyteDifferentiation. Mol Endo. 1992;6:667-676.

16. Sousa CA. Nutritional Therapy in VeterinaryDermatology. Proc 1998 AVMA Convention,Baltimore, MD;713-715.

17. Holick MF. Noncalcemic Actions of 1,25-Dihydroxyvitamin D3 and Clinical Applications.Bone. 1995;17:107S-111S.

18. Huber TL, Laflamme DP, Medleau L, et al.Comparison of Procedures for AssessingAdequacy of Dog Foods. J Am Vet Med Assoc.1991;199:731-734.

19. Mosier JE. Supplementing the Diets of ElderlyDogs. Vet Med. 1985;80:51-55.

20. Sousa CA, Stannard AA, Ihrke PJ, et al.Dermatosis Associated with Feeding GenericDog Food: 13 cases (1981-1982). J Am Vet MedAssoc. 1988;192:676-680.

100 20 30 40 50 60 70

Common Food AllergensThis graph shows the most frequently tested

single-ingredient food challenges and the

percentage of positive responders among 58

food allergic dogs. More than half of the dogs

reacted to more than one protein source.

REFERENCESCarlotti DN, et al. Vet Derm 1990;1:55.Jeffers JG, et al. JAVMA 1996;209:608.

Percent Reactors

Zinc-responsive dermatitis is

generally reported in puppies or

zinc-sensitive breeds although it

can occur in other breeds.

Rice

Wheat*

Dairy

Chicken

Eggs

Corn

Soy

Beef

*Includes wheat products

®

ResearchAbstracts

5

Objective: The objective of thisstudy was to evaluate a commercialhypoallergenic diet in dogs knownto have had a pruritic dermatosisthat was eliminated after a changein diet and to determine if thesedogs would remain symptom-freewhen fed Purina® CNM®

HA-Formula.® †

Methods: Three board certified veterinary dermatologists eachselected canine patients with con-firmed food-related pruritic diseasethat had been controlled at least50% with dietary management.These dogs were each offeredPurina® CNM® HA-Formula® for aseven-day period and then re-eval-uated for a return or worsening ofthe pruritus. At the time of thischallenge, the dogs were at least50% less pruritic than upon originalpresentation. If they were being

treated with antibiotics, anti-yeastmedications, antihistamines or

hyposensitization, or were beingbathed with medicated shampoos,these were not altered. Results: Twenty-four dogs wereidentified that fulfilled the criteriaestablished. All of the dogs hadtheir symptoms of pruritus well-controlled with a variety of diets.Two dogs (8%) experiencedincreased pruritus with the diet. Theremaining 22 (92%) were able to eatPurina® CNM® HA-Formula® with noworsening of the pruritus. Of the

dogs currently maintained on ahome-cooked diet, 100% (n=12)were able to eat Purina® CNM® HA-Formula® with no increase in pruritus.Conclusion: In attempting to identi-fy dogs that are pruritic as a resultof an adverse reaction to somethingthey are being fed, if an owner can-not home-cook a novel two-ingredi-ent diet and chooses to feed a com-mercial diet, feeding Purina® CNM®

HA-Formula® can identify about92% of these patients.

Candace Sousa, DVM, Animal DermatologyClinic, Sacramento, CA; Terese DeManuelle,DVM, Northwest Veterinary Specialists,Clackamas, OR; Helen Power, DVM,Dermatology for Animals, Campbell, CA.

†The name of this brand has changed toPurina Veterinary Diets™ HA HypoAllergenic™

brand canine formula.

Evaluation of the Usefulness of Purina® CNM® HA-Formula® †

Brand Veterinary Diet for Dogs with Pruritic Dermatosisthat Respond to a Change of Diet

This study explores the dynamicchanges in serum and fecal aller-gen specific IgE in a group of dogssuspected of having food hypersen-sitivity on the basis of clinical signs(pruritus and diarrhea), absence ofother pruritic skin diseases andresponse to dietary allergen restric-tion. Five dogs were fed a commer-cial soy hydrolysate diet for nineweeks before oral challenge withmilk. Then, after a 12-day washoutperiod on the hydrolysate, theirregular diet containing multipleallergens including milk, wheat andcorn was reintroduced. Before andafter each dietary change, the dogswere examined and given a clinicalscore reflecting evidence of pruri-

tus. Serum and feces also were collected at these times. A worsen-ing of cutaneous clinical signsdeveloped in all dogs with milkchallenge. Four developed diarrhea,and one vomited. No significantrise in fecal or serum milk specificIgE was noted, except in the dogthat vomited. This was accompaniedby a rise in total, corn and wheatspecific fecal IgE. Dermatitis wasagain induced by challenge withthe regular diet in all dogs. Thiswas accompanied by an increase inallergen specific and total fecal IgEin three of the five dogs. Totalserum IgE rose significantly in alldogs after this challenge. No con-sistent correlation between fecal

and serum allergen specific or totalIgE was observed. In conclusion,local gastrointestinal IgE produc-tion may reflect a specific responseto dietary proteins in the pruriticdog and warrants further investiga-tion as a marker of dietary hypersensitivity.

Jackson HA, Kates CR, Hammerberg B.

This abstract was published in VeterinaryDermatology, Volume 11, Supplement 1,2000, and presented at the Fourth WorldCongress of Veterinary Dermatology, SanFrancisco, September 2000: Abstracts of theFourth World Congress of VeterinaryDermatology, and is reproduced here withpermission from the conference organizersand the publishers, Blackwell Science.

Total and Allergen-Specific Serum and Fecal IgE Responses toDietary Change in Dogs with Suspected Food Hypersensitivity

®

®

A hydrolized-protein diet provides

a suitable alternative to homemade

diets for food-allergic patients.

PurinaResearchReport®

In this issue:

Proper Nutritionfor Healthy SkinDry SkinFood AllergyClient Compliance

Ralston Purina CompanyCheckerboard SquareSt. Louis, MO63164-0001 USA

For additional Informationin the U.S. call 800-222-8387in Canada, call 800-465-3094

©2000 RPCOPrinted in USA121100

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6

Client compliance, whether it relates tocontrolling diet or administering drugs, isoften less than desired. A recent studyevaluated how well pet owners followedthrough when asked to treat their dogs for10 days with a course of antibiotics. Eachowner was provided a prescription for

antibiotics to be administered orally twoor three times daily for various bacterialinfections. Twenty-two percent of theowners initiated treatment on the day ofthe veterinary visit, while 70% initiatedtreatment the next day. Of the 95 dogowners, 44% were judged to have been

100% compliant by providing all of theprescribed medication. Another 44% wereat least 80%compliant,based on thenumber oftablets remain-ing. Compliancewas significantlyhigher for those own-ers who felt their veterinarian providedadequate discussion time with them.Neither treatment regimen (twice vs.three times daily) nor the client s percep-tion of treatment efficacy altered the com-pliance rate.

Source: Grave K and Tanem H. Compliancewith Short-Term Oral Antibacterial DrugTreatment in Dogs. J Sm Anim Pract.

1999;40:158-162.

How Well Do Your Clients Follow Your Instructions?

In previous publications, a subepider-mal linear alignment of mast cells(SLAM) was reported to occur in nearlyhalf of dogs with Malassezia dermatitis.Another study has now evaluated theoccurrence of SLAM in conditions otherthan Malassezia. The retrospectivehistologic study of 419 canine skinbiopsies examined tissues from dogswith demodicosis, sarcoptic mange,dermatophytosis, pemphigus foliaceus,pemphigus erythematosus, discoidlupus erythematosus, systemic lupuserythematosus, erythema multiforme,

dermatomyositis, staphylococcal pyoderma, primary seborrhea, arthro-pod bites, contact hypersensitivity, fleabite hypersensitivity, atopy and foodhypersensitivity. Only three cases(0.07%) were identified with SLAM.Thus, based on these results, SLAMappears much more commonly inMalassezia dermatitis than in otherinflammatory skin diseases.

Source: Beningo KE, Scott DW, Erb HN.Subepidermal Linear Alignment of MastCells in Inflammatory Dermatoses ofthe Dog. Vet Derm. 2000;11:13-16.

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