Journée thématique
Transcription
Journée thématique
COLLOQUE DERMATOLOGIE Conférencier Edmund J. Rosser JR, DMV, DACVD Une présentation de Dimanche 17 novembre 2013 Programme de la journée 8 h 00 – 8 h 30 INSCRIPTION 8 h 30 – 10 h 00 Update on the diagnosis and treatment of food allergy in dogs and cats 10 h 00 – 10 h 30 PAUSE 10 h 30 – 12 h 00 The differential diagnoses and management of feline pruritus 12 h 00 – 13 h 30 BRUNCH et ASSEMBLÉE GÉNÉRALE ANNUELLE 13 h 30 – 15 h 00 Cutaneous drug reactions or ‘’I wouldn’t have seen it if I hadn’t believed it’’ 15 h 00 – 15 h 15 PAUSE 15 h 15 – 16 h 45 Update on the diagnosis and treatment of sebaceous adenitis, symmetrical lupoid onychodistrophy and seasonal flank alopecia 16 h 45 FIN DE LA JOURNÉE EDMOND J. ROSSER JR. DVM, DACVD En 1976, Dr Rosser a obtenu son diplôme en médecine vétérinaire de la Cornell University. Il a ensuite travaillé comme médecin vétérinaire pendant quatre ans avant de faire une résidence en dermatologie à l’Université de Californie (Davis) en 1982. Médecin agrégé de l’American College of Veterinary Dermatology, il s’est joint à la faculté du Michigan State University en 1983 où il est professeur titulaire et directeur de la faculté de dermatologie, en plus d’être chef de la section spécialisée. Dr Rosser a reçu le prix Norden Distinguished Teacher of the Year et, à trois occasions, la Student Chapter of the American Veterinary Medical Association (SCAVMA) lui a décerné le prix d’excellence en enseignement. En 2009, son exceptionnelle contribution à la science et à l’éducation a été soulignée par l’American College of Veterinary Dermatology (ACVD) qui lui a remis le prix d’excellence 2009. Dr Rosser est l’auteur de plus de 70 chapitres de livres et d’articles de journaux dans le domaine de la dermatologie vétérinaire. Il a présenté plus de 200 conférences aux vétérinaires et techniciens vétérinaires à l’échelle locale, régionale, nationale et internationale. Dr Rosser s’intéresse plus particulièrement aux domaines des allergies alimentaires et de la dermatite. Pour joindre Dr Rosser : Michigan State University, College of Veterinary Medicine, Veterinary Medical Center Tél. : 517 353-5420 Courriel: [email protected] DIAGNOSIS AND TREATMENT OF FOOD ALLERGY IN DOGS Edmund J. Rosser Jr., DVM, DACVD Prospective Clinical Evaluation of Food Allergic Dogs and Cats Previous recommendation of a 3 week elimination diet trial was empirical Initial recommendation in this study was to feed a home-cooked restricted diet for 60 days In several instances the results were equivocal after 60 days and the diet was fed an additional 30 days. Data Collected Time elapsed before maximal clinical response on diet and Time elapsed before return of initial clinical signs when fed previous diet Age, breed, sex, clinical signs Responsiveness to glucocorticoids Concurrent disease conditions Final treatment diets Diets Fed Formulated based on known past exposure; Avoided any previously consumed foods; Consisted of home cooked foods Protein sources - lamb, venison, moose, elk, rabbit, duck, goose, goat, ostrich, emu, alligator, kangaroo, pinto beans Carbohydrate source - rice, potatoes, sweet potatoes (yams), rutabagas, oats, barley Results – Canine - Time elapsed before maximal clinical response 1-3 weeks - 13 dogs; 4-6 weeks - 25 dogs; 7-8 weeks - 10 dogs; 9-10 weeks - 3 dogs Since the original study, dogs have now been observed to take as long as 90 days to respond to a homecooked elimination diet trial. Results – Canine - Time elapsed before return of initial clinical signs 1-2 hours - 9 dogs; 1-3 days - 32 dogs; 7-9 days - 3 dogs; 14 days - 1 dog; 6 dogs never fed previous diet “Why All The Fuss About Home-Cooked Elimination Diets?” White SD: Food hypersensitivity in 30 dogs. JAVMA, vol 188 (7):695-698, 1986. 7/13 dogs (54%) with confirmed food allergy on a home-cooked lamb and rice diet, relapsed when feed a commercial canned lamb and rice diet. Jeffers JG, Shanley KJ, Meyer EK: Diagnostic testing of dogs for food hypersensitivity. JAVMA, vol 198 (2):245-250, 1991. 2/13 dogs with confirmed food allergy on a home-cooked lamb and rice diet, relapsed when feed a commercial dry egg and rice diet = 15% error. Sensitivity of serum allergen-specific IgE testing to foods (ELISA) 13 dogs = 14%. Sensitivity of Intradermal Testing to foods in 13 dogs = 10%. Kunkle G, Horner S: Validity of skin testing for diagnosis of food allergy in dogs. JAVMA, vol 200 (5):677680, 1992. Out 28 dogs with a positive skin test reaction to foods, only 3 dogs responded to a home-cooked lamb and rice diet. Rosser EJ: Diagnosis of food allergy in dogs. JAVMA, vol 203 (2):259-262, 1993. 51 food allergic dogs confirmed over a 2-year time while being fed a home-cooked elimination diet for 10 weeks. 3 week trial only adequate for 25% of dogs. Recent data: 25% of dogs on home-cooked elimination diets relapse when fed any form of commercial hypoallergenic dog food. Serologic Test for Food-Specific IgE: Hillier A, Kunkle G: Inability to demonstrate food antigen-specific IgE antibodies in the serum of food th allergic dogs using the PK and oral PK tests. 10 Proceedings of the ACVD Meeting, 1994. No + reactions in 10 know food allergic dogs. Mueller R, Toshalis J: Evaluation of serum allergen-specific IgE for the diagnosis of food adverse reactions in the dog. Vet Derm, 9:167-171, 1998. No + reactions in 8 known food allergic dogs. Ricci R, et al: A Comparison of the Clinical Manifestations of Feeding Whole and Hydrolyzed Chicken to dogs with Hypersensitivity to the Native Protein. Vet Derm, 21:358-66, 2010. No positive reactions in 26 known chicken sensitized dogs. Disclaimer on allergen-specific IgE testing for foods (HESKA): “Not all patients with adverse reactions to food have significant scores on serum IgE tests. The gold standard for determination of food allergies remains the compliant food trial. Diet selection should include patient diet history and should supply a restricted number of one or two novel protein sources to which the patient has not had prior exposure. Diet trials should run a minimum of 10-12 weeks.” Disclaimer on allergen-specific IgE testing for foods (VARL-Liquid Gold): “Elimination diets lasting 6 to 12 weeks - the test method of choice. Feed a single protein source and a single carbohydrate source that the patient has not eaten before. Frustrating for clients and practitioners! Skin testing for food allergy not reliable.” Age At Onset of Clinical Signs - Canine Range of 4 months to 11 years – New record of age of onset of clinical signs related to a food allergy in dogs is 13 year of age!; <1 year old - 17 dogs (33%) – including puppies at 7 weeks of age!; 1-3 years old - 26 dogs (51%); 4-11 years old - 8 dogs (16%) - Compared to Atopic Dermatitis and Flea Allergy Dermatitis, this is older in general for the development of an allergic skin disease. Breeds Affected - Canine Soft-Coated Wheaton Terrier, Dalmatian, Collie, West Highland White Terrier, Chinese Shar Pei, Lhasa Apso, Miniature Schnauzer, Cocker and Springer Spaniels, Labrador Retriever, Golden Retriever, German Shepherd, Bichon Frise Clinical Signs - Canine Non-seasonal pruritus; Most commonly affects the ears/pinnae, feet, inguinal region, axillary region, proximal foreleg, face, neck, perianal/perineal region Chronic, recurrent otitis externa a common problem (Serous Otitis Media observed in 81/104 children from 1-9 years of age related to food allergy in 1 study) Infectious Otitis Media: Defalque VE, Rosser EJ, Petersen AD: Aerobic and anaerobic bacterial microflora th of the middle ear cavity in normal dogs. 20 Proceedings of the ACVD Meeting, 2005. Staphylococci, Streptococci, Enterococci, Bacilli, Bordatella bronchiseptica, NO YEAST. May develop secondary staphylococcal pyoderma or Malassezia dermatitis Possible history of seizures (Food Allergy and seizures in humans: seafoods and soybeans – increased dopamine in CNS) Concurrent diarrhea rare, may have more frequent or softer feces Only clinical sign on presentation: Chronic recurrent pyoderma; Seborrheic dermatitis Response to Glucocorticoids Complete cessation of pruritus - 39% of cases; Partial reduction in pruritus - 44% of cases; No reduction in pruritus - 17% of cases Concurrent Primary Pruritic Skin Diseases Flea Allergy Dermatitis; Atopic Dermatitis; Flea Allergy and Atopic Dermatitis; Flea Collar Hypersensitivity DIAGNOSIS Treat suspected food allergy cases symptomatically for first 6-12 months before recommending an elimination diet trial Rationale For Initial Symptomatic Therapy For 6-12 Months 51 food allergic dogs followed for 3 years: Only 3 dogs re-developed pruritus; 2 dogs became flea allergic; 1 dog became atopic; None of the dogs became pruritic due to the new hypoallergenic treatment diet; All dogs had been eating the initial sensitizing diet for 6-12 months or longer Dogs Started On Elimination Diet Prior To 6-12 Months Of Pruritus 2 cases initially on beef/soy based diets; Placed on lamb based diets after 3 months; Pruritus controlled for 2 months; Pruritus re-developed and dogs found to be reacting to lamb Dogs Started On Elimination Diet Prior To 6 Months Of Pruritus 1 case initially on lamb/rice based diet; Placed on venison based diet after 2 months; Pruritus controlled for 3 months; Pruritus re-developed and dog found to be reacting to venison Theory Of An Immunologic Window Patient is genetically programmed to become sensitized to commonly exposed antigens in the diet after a certain age; At this age, sensitization begins over a 6-12 month time period?; After this time period of programming, the sensitizing immunologic window closes Immunology of Food Allergy IgE mediated food allergy: Common in children - peaks at 1 yr; Consider skin testing and in-vitro serum testing in puppies? Rare in adults ; False negative skin tests in adults Delayed hypersensitivity reactions to foods: More common in adults; Consider patch testing with foods ELIMINATION DIET TRIAL – MINIMUM 12 weeks in duration Protein hydrolysate formulated diets: Reducing the Molecular Weight (Daltons) of a specific protein in the diet Purina CNM Diet - HA-Formula - Hydrolyzed soy, corn starch, canola/coconut oil Purina Gentle Snackers - Hydrolyzed soy, corn starch, canola/coconut oil, oat fiber Hill’s Prescription Diets: Canine z/d Ultra - Hydrolyzed chicken and chicken liver, corn starch, soybean oil Canine z/d Low Allergen - Hydrolyzed chicken and chicken liver, potato (canine), rice (feline), soybean oil Canine Hypoallergenic Treats - Hydrolyzed chicken and chicken liver, corn starch (dogs), rice (feline) soybean oil Royal Canin Veterinary Diet (Waltham) Hypoallergenic HP19 Canine – Hydrolyzed soy, rice, chicken fat, beet pulp, vegetable oil Home-cooked Elimination Diet Trial Restricted diet fed for up to 90 days; Formulate based on known past exposure; Avoid any previously consumed foods Canine Diets Protein sources: Lamb, venison, rabbit, duck, goose, goat, ostrich, emu, alligator, kangaroo, elk, moose Cook by boiling, baking or broiling; Carbohydrate sources: Rice, potatoes, rutabagas – boiled, No instant or minute forms; Sweet potatoes - baked Add nothing to the cooking water; Mix equal portions of protein and carbohydrate (50:50) to approximate the volume of the previous diet; 1 cup of the cooked mixture per 10 pounds of body weight per day; Will need to increase the amount of carbohydrate 2-4 x for most dogs; Use carbohydrate and/or protein treat between meals “Nothing else is to pass the dog’s or cat’s lips for the next 60 days” Discontinue all: Table scrapes; Dog treats; Chewable heartworm preventative - Flavorings in Chewable Heartworm Preventatives: Heartgard and Heartgard Plus - Real beef, corn, soy (Unflavored tablet available); Sentinel and Interceptor - Pork liver, soy; Iverhart Plus - Pork liver; Flavorings in Miscellaneous Chewable Products - Proin (phenylpropanolamine) - Poultry liver; Propalin (phenylpropanolamine) – Beef; Deramaxx (deracoxib) - Pork, soy; Baytril (enrofloxacin) - Pork liver, hydrolyzed soy; Rimadyl (carprofen) Pork liver; Chewable vitamin supplements; Essential fatty acid diet supplements Treatment Diets - Canine Lamb, venison or vegetable and rice based dry diets (Nature’s Recipe) Rabbit and rice based canned diet (Nature’s Recipe) Duck, venison, or salmon and potato based dry or canned diets; lamb and rice based canned diet, egg and rice based dry diet (d/d, Hill’s) Venison, duck, rabbit, or whitefish and potato based canned and dry diets (Innovative Veterinary Diets – Royal Canin - Waltham) Vegetable and potato/oat/rice based dry diet (IVD Select Care Vegetarian Formula) Vegetable and rice/oatmeal/barley/potato based dry diet (Natural Balance Vegetarian Formula) Fish and potato based dry diet (Eukanuba Response Formula FP for Dogs) Salmon, trout and rice dry diet (Purina CNM Diet: LA-Formula); Menhaden fish meal and rice dry diet (Royal Canin - Skin Support SS21) Kangaroo and oat based dry diet (Eukanuba Response Formula KO for Dogs) Fish and sweet potato based dry diets: Wellness Fish and Sweet Potato diet – whitefish, barley, rye flour, menhaden fish meal, canola oil; California Natural Herring & Sweet Potato diet – herring, barley, oatmeal, herring oil, sunflower oil; Natural Balance Sweet Potato and Fish diet – salmon, menhaden fish meal, canola oil; Flint River Ranch “Fish and Chips” Trout and Sweet Potato diet – trout, millet, herring meal, oatmeal, canola oil Duck and sweet potato based dry diet – Fromm Duck and Sweet Potato Formula – barley, rice, oatmeal, egg, millet, tomato pomace, canola oil, cheese, carrots, broccoli, cauliflower, apples, green beans, cranberries, blueberries, chicory root, alfalfa sprouts, garlic, parsley Venison based dog treats – Nature’s Recipe Healthy Skin Venison Dog Treat – soy flour, molasses, garlic powder; Shaffer Venison Farms – Venison Dog Treats – 100% smoked venison Sweet potato based dog treats – Sam’s Yams Sweet Potato dog Chewz – 100% dried sweet potatoes/yams Home Cooked Treatment Diets Protein source: Lamb, venison, rabbit, chicken, turkey, beef, duck, ostrich Carbohydrate source: Rice, potato, sweet potatoes, or rutabagas Essential fatty acid dietary supplement: Derm Caps, EFA-Caps Dicalcium phosphate; Non-flavored, additive free multiple vitamin and mineral supplement Foods Associated With Exacerbation of Clinical Signs Any food items being prepared in the kitchen Meats, cheeses, cooking oils, margarine, breads, odors from various cooked foods Peoples favorite snack foods Popcorn, pretzels, peanuts, cookies (Oreo), potato chips, corn chips, doughnuts, pizza, French fries “The Hoover Hound” New Dilemma Many patients with a possible food allergy that have already eaten and been exposed to “everything but the kitchen sink” Possible cross contamination of commercial diets during processing Prescription and non-prescription hypoallergenic diets Patients reacting to various ingredients used in the processing of commercial diets Cross Contamination of Commercial Diets During Processing Raditic R, Remillard RL, Tater KC: ELISA Testing for Common Food Antigens in Dry Dog Foods Used in th Dietary Elimination Trials. 10 Annual Proceedings of the AAVN Nutrition and Research Symposium, 2010, page 9. 3 of the 4 OTC Venison Canine Dry Foods tested positive for soy, 1 of the 4 tested positive for beef BALANCED HOME-MADE ELIMINATION DIET FOR DOGS 5 pounds cooked potatoes, sweet potatoes, or rutabagas 1 pound cooked venison, ostrich, emu, rabbit, or duck 1 teaspoon Dicalcium phosphate (www.arcatapet.com, Item 13230) 5 tablespoons Safflower Oil (Hollywood Brand only) 1 teaspoon salt substitute (potassium chloride). 2 tablets of Nature Made® Multi Complete - Multiple Vitamin/Mineral Supplement with Iron Feeding Guidelines: Toy Breeds – 4-12 pounds Small Breeds – 12-20 pounds Medium Breeds – 20-50 pounds Large Breeds – 50-80 pounds 1/3 – 2/3 pounds of food/day 2/3 – 1 pound of food/day 1 – 2 pounds of food/day 2 – 3 pounds of food/day DIAGNOSIS AND TREATMENT OF FOOD ALLERGY IN CATS Edmund J. Rosser Jr., DVM, Diplomate, ACVD Prospective Clinical Evaluation of Food Allergic Cats Previous recommendation of a 3 week elimination diet trial was empirical Initial recommendation in this study was to feed a home-cooked restricted diet for 60 days In several instances the results were equivocal after 60 days and the diet was fed an additional 30 days. Data Collected Time elapsed before maximal clinical response on diet Time elapsed before return of initial clinical signs when fed previous diet Age, breed, sex, clinical signs Responsiveness to glucocorticoids Concurrent disease conditions Final treatment diets Diets Fed Formulated based on known past exposure Avoided any previously consumed foods Consisted of home cooked foods Protein sources - rabbit, venison, lamb, duck, goose, ostrich, emu Carbohydrate source - green peas, rarely rice or potatoes Results - Time elapsed before maximal clinical response 1-3 weeks - 4 cats; 4-6 weeks - 7 cats; 7 weeks - 1 cat; 9 weeks - 1 cat; Recent date – diet trials x 12 weeks Results - Time elapsed before return of initial clinical signs 15-30 minutes - 2 cats; 24 hours - 2 cats; 2-3 days - 4 cats; 6-8 days - 4 cats; 10 days - 1 cat; Recent data – feed previous diet x 14 days Age At Onset of Clinical Signs Range of 3 months to 11 years; <1 year old - 3 cats (23%); 1-2 years old - 3 cats (23%); 4 years old - 2 cats (15%); 6-11 years old - 5 cats (39%); Compared to Atopic Dermatitis and Flea Allergy, this is older in general for the development of an allergic skin disease; New Record = 12 years of age Breeds Affected Siamese, Domestic Shorthair, Domestic Longhair Clinical Signs Non-seasonal pruritus; Most commonly affects the ear/pinnae, pre-aural region, neck, periorbital region and face; Miliary type lesions most common (“Miliary dermatitis”) Eosinophilic plaques, Rodent ulcers; Feline symmetrical alopecia Severe excoriations can occur Angioedema, urticaria, conjunctivitis Response to Glucocorticoids Complete cessation of pruritus - 64% of cases; Partial reduction in pruritus - 9% of cases; No reduction in pruritus - 27% of cases Graham-Mize CA, Rosser EJ, Hauptman J: Absorption, bioavailability and activity of prednisone and prednisolone in cats. Adv Vet Derm, vol. 5: 152-158. Greater than a 6-fold difference in Cmax of oral prednisolone (Cmax= 1400 ng/ml) vs. oral prednisone (Cmax= 220 ng/ml) Cmax of oral prednisolone after oral prednisone only 122 ng/ml Results indicate both a decreased gastrointestinal absorption of prednisone compared to prednisolone, and possible decreased conversion of prednisone (inactive form) to prednisolone (active form) by the liver in cats = 12 fold difference Concurrent Primary Pruritic Skin Diseases Flea Allergy Dermatitis; Atopic Dermatitis; Flea Allergy and Atopic Dermatitis; Flea Collar Hypersensitivity DIAGNOSIS Treat suspected food allergy cases symptomatically for first 6-12 months before recommending an elimination diet trial Rationale For Initial Symptomatic Therapy For 6-12 Months 51 food allergic dogs followed for 3 years Only 3 dogs re-developed pruritus; 2 dogs became flea allergic; 1 dog became atopic None of the dogs became pruritic due to the new hypoallergenic treatment diet All dogs had been eating the initial sensitizing diet for 6-12 months or longer Dogs Started On Elimination Diet Prior To 6-12 Months Of Pruritus 2 cases initially on beef/soy based diets; Placed on lamb based diets after 3 months; Pruritus controlled for 2 months; Pruritus re-developed and dogs found to be reacting to lamb Dogs Started On Elimination Diet Prior To 6 Months Of Pruritus 1 case initially on lamb/rice based diet; Placed on venison based diet after 2 months; Pruritus controlled for 3 months; Pruritus re-developed and dog found to be reacting to venison Theory Of An Immunologic Window Patient is genetically programmed to become sensitized to commonly exposed antigens in the diet after a certain age At this age, sensitization begins over a 6-12 month time period? After this time period of programming, the sensitizing immunologic window closes 2 Immunology of Food Allergy IgE mediated food allergy: Common in children - peaks at 1 yr.; Consider skin testing and invitro serum testing in kittens? Rare in adults; False negative skin tests in adults Delayed hypersensitivity reactions to foods: More common in adults; Consider patch testing with foods ELIMINATION DIET TRIAL – MINIMUM 8-12 weeks in duration Protein hydrolysate formulated diets: Reducing the Molecular Weight (Daltons) of a specific protein in the diet Purina Veterinary Diets - HA Formula - Hydrolyzed soy (10,000 Daltons), corn starch, canola/coconut oil – Experimental Trial Diet Only Hill’s Prescription Diets: Feline z/d Ultra (canned) - Hydrolyzed chicken liver (3,000 Daltons), corn starch, soybean oil Feline z/d Low Allergen(dry) - Hydrolyzed chicken liver, rice, soybean oil Feline Hypoallergenic Treats - Hydrolyzed chicken liver, rice, soybean oil Royal Canin Veterinary Diet (Waltham) Hypoallergenic HP23 Feline – Hydrolyzed soy (10,000 Daltons), rice, chicken fat, beet pulp, anchovy oil, soya oil Home-cooked Elimination Diet Trial Restricted diet fed for up to 90 days; Formulate based on known past exposure; Avoid any previously consumed foods; “Nothing else is to pass the cat’s lips for the next 60 days” Discontinue all: Table scrapes; Cat treats; Chewable heartworm preventative; Chewable vitamin supplements; Essential fatty acid diet supplements Feline Diets Protein sources Rabbit, lamb, venison, duck Cook by boiling or broiling Carbohydrate sources Green peas Often refuse rice or potatoes Most often feed protein source alone Treatment Diets - Feline Rabbit and rice based canned diets (Nature’s Recipe) Venison, duck, or rabbit and green pea based canned and dry diets (d/d canned, Hill’s) Lamb and barley based canned diet (Eukanuba Response Formula LB for Cats) Lamb, venison, duck, or rabbit and green pea based canned and dry diets (Royal Canin/Waltham/Innovative Veterinary Diets) 3 Home Cooked Treatment Diets Protein source Lamb, venison, rabbit, chicken, turkey, beef, duck, goose, ostrich, emu Carbohydrate source Green pea, rice, potato or sweet potatoes Essential fatty acid dietary supplement Derm Caps, EFA-Caps Dicalcium phosphate Non-flavored, additive free multiple vitamin and mineral supplement Taurine for cats Foods Associated With Exacerbation of Clinical Signs Any food items being prepared in the kitchen - “The Counter Cat” Meats, cheeses, cooking oils, margarine, breads, odors from various cooked foods Peoples favorite snack foods Popcorn, pretzels, peanuts, cookies (Oreo), potato chips, corn chips, doughnuts, pizza, French fries New Dilemma Many patients with a possible food allergy that have already eaten and been exposed to “everything but the kitchen sink” Possible cross contamination of commercial diets during processing Prescription and non-prescription hypoallergenic diets Patients reacting to various ingredients used in the processing of commercial diets BALANCED HOME-MADE ELIMINATION DIET FOR CATS ½ pound cooked potatoes, rice, or green peas 1 pound cooked lamb, venison, ostrich, emu, rabbit, or duck 1 teaspoon Dicalcium phosphate ½ tablespoon Safflower Oil (Hollywood Brand only) 2 teaspoons light salt 2 tablets of Nature Made® Multi Complete - Multiple Vitamin/Mineral Supplement with Iron 350 mg Taurine Feeding Guidelines: Broil, boil, or bake lamb and grind or finely chop. Add salt to cooking water for rice, potatoes, or green peas. Mix the safflower oil, Dicalcium phosphate, vitamin/mineral supplement, and taurine with the rice, potatoes, or green peas, and then add the mixture to the meat puree. Keep refrigerated and warm in microwave to increase palatability. Feed 2½ ounces/5 pounds of cat/day. 4 FELINE PRURITUS: DIAGNOSIS AND MANAGEMENT Edmund J. Rosser Jr., DVM, Diplomate ACVD Professor of Dermatology Department of Small Animal Clinical Sciences Michigan State University College of Veterinary Medicine East Lansing, MI 48824-1314 1. Differential Diagnosis of Feline Pruritus a. Feline “Miliary Dermatitis” b. “Feline Symmetrical Alopecia” 2. Feline Miliary Dermatitis a. Etiology i. A cutaneous reaction pattern, not a specific disease entity. b. Clinical Features i. Small focal to diffuse papular eruptions with small crusts. ii. Usually pruritic, excoriations may occur. c. Flea Allergy Dermatitis i. Affects the dorsal lumbo-sacral region, caudo-medial thighs, ventral abdomen, and flanks. May also affect the head and neck region, may become generalized. ii. Warm weather seasonal or non-seasonal pruritus – geographic differences. d. Cutaneous Adverse Food Reactions - “Food Allergy” i. Affects the pre-aural region, pinnae, neck, periorbital region, face. ii. Severe excoriations may occur. iii. Non-seasonal pruritus, concurrent GI signs rare! e. Atopic Dermatitis (“Catopy”) i. May mimic the distribution patterns of Flea Allergy or Food Allergy, or may also present with lesions of the forelegs, rear legs, ventral abdomen and chest. ii. May be warm weather seasonal, present year round with exacerbations in warm weather, or non-seasonal. f. Parasitic Causes i. Presence of “miliary lesions” implies a hypersensitivity response. ii. Cheyletiellosis (“Walking Dandruff”) - affects primarily the dorsal trunk, excess scaling a major sign. iii. Notoedric Mange (Feline Scabies) - affects the pinnae, face, periorbital region, neck (“Head Mange”) – heavy crusts/scales. May extend to the feet, perineum. iv. Trombiculosis (“Chiggers”) - affects ground contact areas – legs, feet, ears, and ventrum with orange colored crusts. g. h. i. j. k. v. Otoacariasis (Ectopic Ear Mites) - may mimic the distribution patterns of Flea Allergy, Food Allergy, or Atopy. Usually has concurrent otitis externa. vi. Demodicosis - Demodex cati – long slender mite. Affects the periorbital region, head, and neck with concurrent ceruminous otitis externa. vii. Pediculosis (Lice) - Felicola subrostrata. Affects primarily the dorsal trunk. Presence of “nits” on hair shafts. viii. Cat Fur Mite - Lynxacarus radovsky. Affects primarily the dorsal trunk. “Salt and pepper” like scale. ix. Intestinal Parasite Hypersensitivity - roundworms, hookworms, whipworms, tapeworms, Coccidia. May mimic the distribution patterns of Flea Allergy, Food Allergy, or Atopy. Fungal Causes i. Dermatophytosis - may mimic the distribution patterns of Flea Allergy, Food Allergy, or Atopy. Additional areas of patchy alopecia, scales. History of other pets or humans in the household with skin lesions. ii. Malassezia Dermatitis - secondary complication. Autoimmune Causes i. Pemphigus Foliaceus - affects the nasal planum, periorbital region, and pinnae. May become generalized. May be systemically ill. ii. Pemphigus Erythematosus - lesions limited to the nasal planum, periorbital region, pinnae. Immune Mediated Causes i. Cutaneous Drug Reaction - often mimics the distribution pattern of Food Allergy. Methimazole reported, Propranalol. ii. Hypereosinophilic Syndrome - multisystemic organ involvement. Anorexia, vomiting, diarrhea, weight loss. Generalized miliary lesions and pruritus. Neoplastic Causes i. Cutaneous Mastocytosis - most commonly affects the head and neck region, may be generalized. Geriatric Siamese cats predisposed. Gastrointestinal ulcers, coagulation disorder. ii. Epitheliotropic Cutaneous Lymphoma (Mycosis Fungoides) - the “Great Imitator”. Viral Causes i. Feline Herpes Virus - affects the nasal region and face. May have a history of previous upper respiratory infections. May have history of conjunctivitis and/or oral ulcers. ii. FeLV and FIV Associated Skin Lesions - chronic “miliary dermatitis” with concurrent systemic illness. l. Idiopathic Causes i. Idiopathic Sterile Granuloma and Pyogranuloma - may mimic the distribution pattern of Food Allergy. Spontaneous remission may occur. ii. Idiopathic “Miliary Dermatitis” - relatively rare. A diagnosis of exclusion! 3. Feline Symmetrical Alopecia a. Etiology i. A symptom of several possible underlying diseases. ii. Not a specific disease entity. A result of excess symmetrical licking with the “barbs” of the tongue fracturing the hair shafts. iii. Rarely is the alopecia spontaneous. b. Clinical Features i. A non-inflammatory, symmetrical alopecia. ii. Most commonly affects the ventral abdomen, inguinal region, perineum, dorsal lumbosacral region, medial and posterior thighs. iii. May also affect the entire ventrum, anterior and medial forelegs. iv. May affect “anywhere the cat can lick”. v. Close inspection reveals diffuse thinning of hair rather than “total” alopecia. Owner often unaware of excess grooming behavior. vi. May be “secretive” or nocturnal groomers. vii. Problem with “hair balls”. c. Flea Allergy Dermatitis i. Most commonly affects the dorsal lumbo-sacral region, caudo-medial thighs, ventral abdomen, and flanks. ii. Warm weather seasonal or non-seasonal pruritus – geographic differences. d. Cutaneous Adverse Food Reactions - “Food Allergy” i. Often affects the ventral abdominal, inguinal regions. ii. May also have “miliary lesions” in the pre-aural region, pinnae, neck, periorbital region, and face. iii. Non-seasonal pruritus, concurrent GI signs rare! e. Atopic Dermatitis (“Catopy”) i. Most commonly affects the medial thighs, entire ventrum, forelegs. ii. May mimic the distribution patterns of Flea Allergy or Food Allergy. iii. May be warm weather seasonal, present year round with exacerbations in warm weather, or non-seasonal. f. Parasitic Causes i. Cheyletiellosis (“Walking Dandruff”) - affects primarily the dorsal trunk with excess scaling a major sign. Symmetrical alopecia of the ventral abdomen. ii. Demodicosis - Demodex gatoi – short stubby mite. Symmetrical alopecia of the ventral abdomen. iii. Otoacariasis (Ectopic Ear Mites) - may mimic the distribution patterns of Flea Allergy, Food Allergy, or Atopy. Usually has concurrent otitis externa. g. h. i. j. k. iv. Pediculosis (Lice) - Felicola subrostrata. Affects primarily the dorsal trunk. Presence of “nits” on hair shafts. v. Cat Fur Mite - Lynxacarus radovsky. Affects primarily the dorsal trunk. “Salt and pepper” like scale. vi. Intestinal Parasite Hypersensitivity - roundworms, hookworms, whipworms, tapeworms, Coccidia. May mimic the distribution patterns of Flea Allergy, Food Allergy, or Atopy. Fungal Causes i. Dermatophytosis - most commonly has areas of “patchy” alopecia, scales. History of other pets or humans in the household with skin lesions. ii. Malassezia Dermatitis - secondary complication. Brownish discoloration to the skin. Miscellaneous Causes i. Hyperthyroidism - excess grooming from “hyperexcitable” behavior. ii. Lower Urinary Tract Infections - affects the ventral abdomen. iii. Impacted anal glands (Anal sacculitis) - affects the perineal, perianal region. Endocrine Causes i. Hyperadrenocorticism - spontaneous symmetrical, truncal alopecia, easily epilated hairs. May have concurrent “skin fragility”. ii. Hypothyroidism - ???? Neoplastic Causes i. Pancreatic Paraneoplastic Alopecia - geriatric cats. Alopecia most commonly on the ventrum and legs. Skin takes on a “shiny” appearance. Easily epilated hairs. Concurrent anorexia, lethargy. Psychogenic Causes i. Feline Psychogenic Alopecia - an anxiety neurosis. Often due to a disturbing influence. New puppy or kitten, barking dogs, new baby, recent move, etc. Emotional breeds: Burmese, Siamese, Abyssinian. Sequela to previous pruritic skin disease. Most commonly affects the easiest areas to reach; medial thighs, ventral abdomen, medial forelegs. Darkened hair color in Siamese cats due to melanin pigment increase with cooler skin temperature. 4. Feline Pruritus – Diagnosis a. Feline Miliary Dermatitis: Flea Allergy Dermatitis i. Distribution pattern of lesions - posterior 1/3 of the body. ii. Seasonal pruritus. iii. Intradermal testing with flea antigen, in-vitro testing for flea. iv. Response to intense flea treatment protocol. b. Feline Miliary Dermatitis: Cutaneous Adverse Food Reactions -“Food Allergy” i. Distribution pattern of lesions - anterior 1/3 of the body. c. d. e. f. g. h. i. ii. Non-seasonal pruritus. iii. Home cooked, novel protein and carbohydrate elimination diet 8-12 weeks in duration. iv. Protein Hydrolysate Diets 1. Reduced molecular weight (Daltons) of specific protein in diet. 2. Most “allergenic” proteins are in range of 14,000 – 70,000 Daltons. 3. Hydrolyzed proteins in the range of 1,000 – 12,000 Daltons. v. Feline Commercial Protein Hydrolysate Diets 1. Royal Canin Veterinary Diet: Feline Hypoallergenic HP23 hydrolyzed soy, chicken fat, rice, beet pulp, fish oil. 2. Hill’s Prescription Diets: Feline z/d Low Allergen – hydrolyzed chicken and chicken liver, rice, vegetable oil. Feline Miliary Dermatitis: Atopic Dermatitis (“Catopy”) i. Mimics Flea Allergy and Food Allergy. ii. Seasonal or non-seasonal pruritus. iii. Intradermal testing with aeroallergens. iv. Aeroallergen specific IgE immunoassay. Feline Miliary Dermatitis: Parasitic Causes i. Distribution pattern of lesions ii. Skin scrapings, Scotch tape preparations, flea combing, fecal flotation, vacuum technique. iii. Response to empirical parasiticidal treatments - lime sulfur dips vs. selamectin vs. ivermectin vs. fipronil spray. Feline Miliary Dermatitis: Dermatophytosis i. Areas of patchy alopecia, scales. ii. History of other pets or humans in the household with skin lesions. iii. Wood’s lamp examination, KOH prep, fungal cultures, skin biopsy. Feline Miliary Dermatitis: Pemphigus Foliaceus i. Affects the nasal planum, periorbital region, and pinnae. ii. May become generalized, and systemically ill. iii. Histopathology - subcorneal pustules with acantholytic cells. Feline Miliary Dermatitis: Pemphigus Erythematosus i. Lesions limited to the nasal planum, periorbital region, pinnae. ii. Histopathology - subcorneal pustules with acantholytic cells. Feline Miliary Dermatitis: Cutaneous Drug Reaction i. Distribution pattern of lesions - mimics Food Allergy. ii. History of drug use and response to drug withdrawal. iii. Histopathology – varied. Feline Miliary Dermatitis: Hypereosinophilic Syndrome i. Many organs involved, anorexia, vomiting, diarrhea, weight loss. ii. Moderate to marked eosinophilia. iii. Histopathology – superficial and deep perivascular to interstitial dermatitis with eosinophils. j. Feline Miliary Dermatitis: Neoplastic Causes i. Cutaneous Mastocytosis - geriatric Siamese cats predisposed. Gastrointestinal ulcers, coagulation disorder. ii. Epitheliotropic Cutaneous Lymphoma (Mycosis Fungoides) - the “Great Imitator”. k. Feline Miliary Dermatitis: Feline Herpes Virus i. Distribution pattern of lesions - affects the nasal region and face. ii. History of previous upper respiratory infections, conjunctivitis, oral ulcers. iii. Histopathology - epithelial cell intranuclear inclusion bodies. iv. PCR for Feline Herpes virus 1. l. Feline Miliary Dermatitis: Idiopathic Sterile Granuloma and Pyogranuloma i. Distribution pattern of Food Allergy. ii. Histopathology - Perifollicular pyogranulomatous dermatitis or; Preauricular xanthogranuloma – a diffuse granulomatous dermatitis with multinucleated giant cells. iii. Chronic steroid or megestrol acetate use. m. Feline Miliary Dermatitis: Idiopathic “Miliary Dermatitis” i. Histopathology - superficial perivascular dermatitis with neutrophils, eosinophils, plasma cells, mast cells. 5. Feline Symmetrical Alopecia - Diagnosis a. Spontaneous vs. Post-traumatic alopecia i. Physical exam - rarely is area completely alopecic, hairs do not easily epilate. ii. Trichogram - anagen bulbs with broken distal ends vs. telogen bulbs with fine pointed ends. b. Feline Symmetrical Alopecia: Flea Allergy Dermatitis i. Distribution pattern of lesions - posterior 1/3 of the body. ii. Seasonal pruritus. iii. Intradermal testing with flea antigen or in-vitro testing for flea. iv. Response to intense flea treatment protocol. c. Feline Symmetrical Alopecia: Cutaneous Adverse Food Reactions -“Food Allergy” i. Often affects the ventral abdominal, inguinal regions. ii. Non-seasonal pruritus. iii. Home cooked, novel protein and carbohydrate elimination diet 8-12 weeks in duration. iv. Protein Hydrolysate Diets 4. Reduced molecular weight (Daltons) of specific protein in diet. 5. Most “allergenic” proteins are in range of 14,000 – 70,000 Daltons. 6. Hydrolyzed proteins in the range of 1,000 – 12,000 Daltons. ii. Feline Commercial Protein Hydrolysate Diets d. e. f. g. h. i. j. k. l. 1. Royal Canin Veterinary Diet: Feline Hypoallergenic HP23 hydrolyzed soy, chicken fat, rice, beet pulp, fish oil. 2. Hill’s Prescription Diets: Feline z/d Low Allergen – hydrolyzed chicken and chicken liver, rice, vegetable oil. Feline Symmetrical Alopecia: Atopic Dermatitis (“Catopy”) i. Most commonly affects the medial thighs, entire ventrum, and forelegs. ii. Seasonal or non-seasonal pruritus. iii. Intradermal testing with aeroallergens. iv. Aeroallergen specific IgE immunoassay. Feline Symmetrical Alopecia: Parasitic Causes i. Most frequently Cheyletiellosis and Demodicosis. ii. Skin scrapings, Scotch tape preparations, flea combing, fecal flotation, vacuum technique. iii. Response to empirical parasiticidal treatments. Lime sulfur dips vs. selamectin vs. ivermectin vs. fipronil spray. Feline Symmetrical Alopecia: Dermatophytosis i. Most commonly have areas of “patchy” alopecia, scales. ii. History of other pets or humans in the household with skin lesions. iii. Wood’s lamp examination, KOH prep, fungal cultures, skin biopsy. Feline Symmetrical Alopecia: Hyperthyroidism i. Basal total serum thyroxine (T4). Feline Symmetrical Alopecia: Lower Urinary Tract Infections i. Urine culture and susceptibility. Feline Symmetrical Alopecia: Impacted anal glands (Anal sacculitis) i. Anal gland extirpation. Feline Symmetrical Alopecia: Hyperadrenocorticism i. Spontaneous symmetrical, truncal alopecia, easily epilated hairs. ii. May have concurrent “skin fragility”. iii. Dexamethasone suppression test - 0.1 mg/kg – baseline, 4 & 8 hours post dexamethasone. iv. ACTH stimulation test - measure both cortisol and progesterone. Feline Symmetrical Alopecia: Pancreatic Paraneoplastic Alopecia i. Geriatric cats with alopecia most commonly on the ventrum, legs. ii. Skin takes on a “shiny” appearance. iii. Histopathology - marked follicular atrophy with a mild mononuclear perivascular dermatitis. iv. Abdominal ultrasound. v. Serum trypsin-like immonoreativity (TLI). Feline Symmetrical Alopecia: Feline Psychogenic Alopecia i. History of change in cat’s environment. ii. Non-responsive to Prednisolone. iii. Elizabethan collar response test. iv. Histopathology - normal or very mild superficial perivascular dermatitis. 6. Feline Pruritus – Treatment a. Flea Allergy Dermatitis i. Environmental treatment - pyrethroid + pyriproxifin; boric acid or sodium polyborate powder. ii. Patient treatment - Imidacloprid – q14d + leufenuron – q30d; Fipronil + methoprene – q21d. iii. Aqueous hyposensitization with flea salivary antigen. b. Cutaneous Adverse Food Reactions – “Food Allergy” i. Commercial diet avoiding the known offending food source. ii. Nature’s Recipe – rabbit and rice canned diet. iii. Hill’s Prescriptions Diets: Feline d/d – venison and green pea based dry or canned diet; duck or rabbit and green pea based dry diet. iv. Eukanuba Response Formula LB for Cats – lamb and barley based canned diet. v. IVD – Royal Canin – Waltham: duck, rabbit, venison, or lamb and green pea – canned or dry diets. vi. Home-cooked Treatment Diets - “novel” protein and carbohydrate source, essential fatty acid dietary supplement, safflower oil, dicalcium phosphate, non-flavored, additive free vitamin and mineral supplement, and taurine for cats. c. Atopic Dermatitis (Catopy) i. Allergen specific immunotherapy (ASIT). ii. Prednisolone (not Prednisone) - 1 mg/kg q12h x 7 d, then q24h x 7 d, then q48h at lowest possible dose to control pruritus. iii. Cyclosporine – 5 mg/kg q24h. d. Parasitic Diseases i. Lime sulfur – q7d x 4 weeks - Cheyletiella, Notoedres, Trombicula, Lynxacarus, Demodex gatoi, Felicola subrostrata. ii. Selamectin – q14d x 3 treatments - Cheyletiella, Notoedres, Otodectes. iii. Fipronil spray – q30d - Cheyletiella, Notoedres, Felicola subrostrata. iv. Ivermectin - 200 ug/kg q7d x 4 weeks - Cheyletiella, Notoedres, Otodectes; 200-300 ug/kg q24h - Demodex cati. v. Amitraz – 125 ppm q14d - Cheyletiella, Notoedres, Trombicula, Lynxacarus, Demodex gatoi, Demodex cati, Felicola subrostrata. e. Dermatophytosis: Systemics i. Itraconazole - 5-10 mg/kg q24h with food for 4-6 weeks. ii. Terbinafine - 30 mg/kg q24h for 4-6 weeks. iii. Lufenuron - 60-100 mg/kg q30d x 2 treatments. f. Dermatophytosis: Topicals i. Lime sulfur - twice weekly for 4-6 weeks. ii. Enilconazole topical solution (10%) - twice weekly for 4-6 weeks. iii. Miconazole shampoo and leave on rinse 2% (ResiZole) - twice weekly for 4-6 weeks. g. Pemphigus foliaceus and Pemphigus erythematosus i. Prednisolone (not Prednisone) - Induction dosage - 2 mg/kg q12h; Maintenance dosage - gradually decrease the dosage every 2 weeks to prevent a relapse. ii. Chlorambucil - Induction dosage – 0.1 mg/kg q48h; Maintenance dosage – 0.05 mg/kg q48h. h. Drug Eruption i. Discontinue suspected drug. ii. Avoid chemically related or similar drugs. iii. Best advice: “Do no harm!” i. Hypereosinophilic Syndrome i. Prednisolone (not Prednisone) - Induction dosage - 2 mg/kg q12h; Maintenance dosage - gradually decrease the dosage every 2 weeks to prevent a relapse. ii. Alpha interferon - 30-60 IU orally q24h. iii. Poor prognosis. j. Cutaneous Mastocytosis i. Spontaneous remission may occur. ii. Prednisolone (not Prednisone) - Induction dosage - 2 mg/kg q12h; Maintenance dosage - gradually decrease the dosage every 2 weeks. iii. Chlorambucil - Induction dosage – 0.1 mg/kg q48h; Maintenance dosage – 0.05 mg/kg q48h. k. Epitheliotropic Cutaneous Lymphoma (Mycosis Fungoides) i. Prednisolone and Chlorambucil – as above. ii. Lomustine - 60 mg/m2 q21d. l. Feline Herpes Virus i. Pure lysine granules (78.8% lysine) - ¼ teaspoon (~570 mg) q12h for life. ii. L-lysine tablets (without propylene glycol) - 250-500 mg/cat for life. iii. Imiquimod 5% cream - 3 times weekly. iv. Alpha interferon - 30-1000 IU orally q24h. m. Hyperadrenocorticism i. Unilateral/Bilateral adrenalectomy - Mineralocorticoid maintenance: Fludrocortisone acetate – 0.1-0.3 mg/cat or Desoxycorticosterone pivalate – 2.2 mg/kg SQ once monthly. Glucocorticoid maintenance: Prednisolone – 1.25-2.5 mg/cat/day ii. Metyrapone – 65 mg/kg q12h. n. Pancreatic Paraneoplastic Alopecia i. Screen for evidence of metastasis. ii. Radiographs and ultrasound - liver, diaphragm, lungs. iii. Partial pancreatectomy. o. Feline Psychogenic Alopecia i. Correct or remove disturbing influence. ii. Mood altering drugs 1. 2. 3. 4. 5. Clomipramine – 1.25-2.5 mg/cat/d. Amitriptyline – 5 mg/cat q12h. Hydroxyzine – 10 mg/cat q12h. Paroxetine HCl – 2.5 mg/cat q24h. Phenobarbital – 1/8 grain BID; increase by 1/8 grain every 2-3 weeks until cat is sedated or stops licking. 6. Progestational compounds (last resort) – Megestrol acetate (Ovaban®) – 2.5 – 5.0 mg/cat q48h until hair regrows, then q 7 days as maintenance. DIAGNOSIS AND M ANAGEMENT OF CUTANEOUS DRUG REACTIONS IN DOGS AND CATS Edmund J. Rosser Jr., DVM, Diplomate ACVD PATHOGENESIS: Immunologic Type I, II, III, IV hypersensitivity reactions Nonimmunologic Related to pharmacology of the drug; Predictable, dose dependent Route of administration Oral; Topical; Injectable; Inhalation Clinical Presentations: Erythema multiforme Toxic epidermal necrolysis Pemphigus foliaceus Vaccine reaction Cutaneous vasculitis Lichenoid Drug Eruption Unique Feline Reactions: Miliary dermatitis reaction Vaccine reaction Injection site fibrosarcomas ERYTHEM A MULTIFORME Drug-induced apoptosis - Programmed cell death Acute onset of lesions; Erythematous macules; “Target lesions”; Urticarial plaques; Vesicles and bullae; Concurrent systemic illness; Fever, depression, anorexia Mucous membrane involvement; Vesicles, bullae, ulcers Erythema multiforme major or Stevens-Johnson syndrome - Can be life threatening Drugs implicated Aurothioglucose; Cephalexin, chloramphenicol, gentamicin, trimethoprim sulfas, ormetoprim sulfas, tetracycline; Diethylcarbamazine, levamisole; L- thyroxine, phenobarbitol TOXIC EPIDERM AL NECROLYSIS Severe erythema multiforme? Massive and sudden apoptosis Diffuse erythematous rash; Vesicles and bullae; Full thickness skin sloughing and ulcers May affect footpads, mucous membranes Lesions usually painful Concurrent fever, anorexia, lethargy, depression Secondary sepsis a problem; Often a fatal disease Drugs implicated Penicillins, cephalosporins, trimethoprim sulfas; Griseofulvin; Levamisole; 5- fluorocytosine; Topical flea dips (D-limonene) DRUG-INDUCED PEMPHIGUS Mimics Pemphigus foliaceus Acute, transient pustular eruptions; Subsequent crusts, scales, erosions, epidermal collarettes; Variable distribution patterns; Systemic illness rare Drugs implicated Ampicillin, cephalosporins, sulfonamides; Diethylcarbamazine, thiabendazole; Cimetidine, procainamide VACCINE REACTIONS Most commonly observed at site of a subQ or IM vaccination: Rabies, DHLP- Parvo Can occur from weeks to months post-vaccination - Focal area of alopecia and hyperpigmentation Breed predisposition Poodle, Bichon Frise; Shih Tzu, Lhasa Apso; Miniature Schnauzer, Yorkshire Terrier, Bedlington Terrier, Silk y Terrier Most spontaneously resolve over several months; Lesion may remain static Area of alopecia and hyperpigmentation can gradually enlarge over months to years Treatment Tincture of time; Surgical excision; Pentoxifylline (Trental) - 15-30 mg/kg TID x 3 months CUTANEOUS VASCULITIS Palpable purpura, hemorrhagic bullae; Craterform ulcers, full thickness skin sloughing Acrocyanosis of distal extremities; Large areas of erythematous or purplish skin; Does not blanch on dioscopy; Lesion often painful; Pitting edema of distal extremities; Concurrent systemic illness - Anorexia, depression, fever Drugs implicated Penicillins, sulfonamides, cephalosporins, dexamethasone; DHLP- Parvo vaccine LICHENOID DRUG ERUPTION Solitary to multiple papillomatous or plaque-like lesions Drugs implicated: Cyclosporine (Atopica, Neoral, Gengraf) MILIARY DERM ATITIS REACTION Miliary lesions - Affects head, face, neck regions; Intense pruritus Mimics “food allergy” Drugs implicated: Methimazole (Tapazol), Propranolol VACCINE REACTION Injection site fibrosarcomas Interscapular and femoral regions - Associated with either subQ or IM injections Tumor may develop 1-2 years post –vaccination; Vaccines implicated: FeLV, Rabies, FVRCP DIAGNOSIS OF CUTANEOUS DRUG REACTIONS History Observed reaction does not resemble pharmacologic action Prior exposure to drug may have been well tolerated Reaction can be reproduced by small amounts of drug Reaction consistent with a known hypersensitivity response Reaction occurs within several days of drug exposure Resolution within several days of drug withdrawal 2 Drug rechallenge Proves cause and effect relationship; Clinical signs often more severe; Outcome can be fatal Erythema Multiforme: Histopathology - Hydropic interface dermatitis; Dyskeratotic keratinocytes with satellitosis; Superficial perivascular infiltrates with mononuclear cells Toxic Epidermal Necrolysis: Histopathology - Hydropic degeneration of basal cells; Coagulation necrosis of epidermis; Absence of dermal inflammation; Dermoepidermal separation and bullae formation CLINICAL CRITERIA EMm EMM SJS OVE TEN Flat or raised, focal or multifocal, target lesions Yes Yes No No No Number of mucosa involved <1 >1 >1 >1 >1 Erythematous or purpuric, macular or patchy eruption <50% <50% >50% >50% >50% 10-30 >30% Epidermal detachment <10% <10% <10% Olivry T et al: Erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis in the dog: Clinical classification, drug exposure, and histopathological correlations. Proceedings of the Autumn Meeting of the British Veterinary Dermatology Study Group, 1998, York, United Kingdom. Pemphigus Foliaceus: Histopathology - Subcorneal pustules; Acantholytic cells; Neutrophils, eosinophils; Involvement of hair follicles Vaccine Reaction: Histopathology - Vasculitis, panniculitis; Dermal edema; Atrophic hair follicles; Hydropic degeneration of basal cells Cutaneous Vasculitis: Histopathology - Most commonly leukocytoclastic; Neutrophils in vessel walls - “Nuclear dust”; Fibrinoid degeneration, thrombi; Perivascular hemorrhage and edema LICHENOID DRUG ERUPTION: Histopathology - Psoriasiform lichenoid dermatosis – with or without papillomavirus UNIQUE FELINE REACTIONS: Miliary dermatitis: Histopathology - Epidermal crusts, spongiosis; Neutrophilic, eosinophilic vesicopustules; Eosinophilic perivascular infiltrates Vaccine Reactions: Histopathology - Fibrosarcoma TREATMENT Discontinue suspected drug; Avoid chemically related or similar drugs W hen multiple drugs are present: all should be discontinued 3 Best advice: “Do no harm!” For Idiopathic cases (Erythema multiforme, cutaneous vasculitis, miliary dermatitis) – consider hydrolysate treated or home-cooked elimination diet trial Supportive Therapy - IV Fluids Systemic antibiotics in septic patients Broad spectrum initially: Cephalexin - 22 mg/kg TID Gram negative organisms - Ciprofloxacin - 22 mg/kg SID Immunosuppressive Drugs Extremely controversial - May actually be contraindicated; Increased risk of infections, delayed healing; Indicated in drug induced Erythema Multiforme major Corticosteroids: Prednisolone - 2 mg/kg SID-BID Immune Modulating Drugs: Cyclophosphamide - 2 mg/kg SID; Cyclosporine (Neoral, Gengraf, Atopica) - 5 mg/kg SID-BID; Azathioprine (Imuran) - 2 mg/kg SID, Pentoxifylline (Trental) – 15-30 mg/kg TID 4 SEBACEOUS ADENITIS Edmund J. Rosser Jr., DVM, Diplomate ACVD Professor and Head of Dermatology Department of Small Animal Clinical Sciences Michigan State University, College of Veterinary Medicine ETIOLOGY Unknown; May be an immune mediated disease. A genetically inherited defect – autosomal recessive trait. Keratinization abnormality with obstruction of sebaceous duct? Abnormality in sebaceous lipids – necessary for dissolution of external root sheath CLINICAL FEATURES - 2 forms Sebaceous Adenitis with Hyperkeratosis – Long Coated Breeds Seen in all color variants of standard poodles (may be similar in other long-coated breeds of dogs such as Samoyeds, Akitas, and Havanese). A symmetrical partial alopecia and excess scaling with follicular casts. Remaining hair is dull and brittle. Affects dorsal planum of the nose, top of head, dorsal neck and trunk, tail and pinnae. Non-pruritic and no offensive odor May develop secondary bacterial folliculitis with pruritus. Hair may become straight and lose its “curl”. Granulomatous Sebaceous Adenitis – Short Coated Breeds Affects short-coated breeds of dogs - Vizslas, Weimaraners, Dachshunds Begins as a moth-eaten alopecia with minimal to no scaling. Primarily affects the trunk, head and ears; Non-pruritic DIAGNOSIS Histopathology Initial nodular granulomatous to pyogranulomatous inflammation at the level of the sebaceous glands; Depending on the type, there may or may not be prominent hyperkeratosis; Chronic cases develop a complete loss of sebaceous glands with fibrosis, atrophy of hair follicles and in some cases complete loss of the adnexa with fibrosis. Treatment Propylene glycol - a hygroscopic lipid solvent that penetrates the horny layer and increases water content. 50-75% propylene glycol with water-applied daily as a spray. Bath Oil Treatments (light mineral oil) – 50:50 mixture of bath oil and water, spray over the entire body, rub into the hair coat well, allow to soak for 1-2 hours. Remove oil by bathing with dish soap 2-3 times, and then finish with a moisturizing shampoo and conditioner/crème rinse for the final bathing. Repeat q 7 days for the first month, the q 14-30 days prn. EFA Supplement - Derm Caps ES - 1 capsule BID; Evening Primrose Oil (EPO) - 500 mg BID. Anti-seborrheic shampoos, conditioners and emollients have been of little benefit. Treat secondary pyoderma if present. Isotretinoin (Accutane®) - 1 mg/kg SID-BID: Side effects – KCS, pruritus, erythema, lethargy, vomiting, abdominal distention, collapse, swollen tongue, hyperactivity Acetretin (Soriatane®) - 1 mg/kg SID-BID: Side effects – KCS, dry mucous membranes, generalized joint stiffness, alopecia, pruritus, cracked foot pads, myalgia (muscles of mastication), vomiting. Retinoid toxicities - Toxicities – increased liver enzymes (ALT, AST), increase in cholesterol and triglycerides, blood dyscrasias (increased platelets, decreased RBC, WBC) Teratogenic – marked decrease in availability for dogs: requires registration and forms. Recent strict regulations – registered physicians only! Cyclosporine (Neoral, Gengraf, Atopica) - 5 mg/kg BID - Major side effect – vomiting; Cerenia – 2 mg/kg given 1 hour prior to dosing. Other side effects – diarrhea/anorexia/weight loss; gingival hyperplasia; verrucous skin lesions; hirsutism; lameness; hyperglycemia; opportunistic infections; neoplasia (lymphoma?). Retinol (Vitamin A) – 8,000-20,000 IU – SID-BID Surface Lipids: Dermoscent Essential 6 – PUFA’s, rosemary oil, vitamin E – apply weekly; Allerderm® Spot-On (Virbac) – ceramides, fatty acids – apply 1-3 times weekly Tetracycline and Niacinamide – 22 mg/kg of each drug TID, not to exceed 500 mg TID for each drug - Tetracycline toxicity – hepatotoxic; Niacinamide side effects – anorexia, lethargy Doxycycline – 5-10 mg/kg SID, with or without Niacinamide - Hepatotoxic at higher doses PROGNOSIS Akitas – tends to be more severe, chronic recurrent pyoderma more f a problem, possible signs of systemic illness. Standard Poodles – aesthetic disease, secondary pyoderma rare, difficult to regrow “normal” hair coat, however recent use of lipid treatments are encouraging. Short Coated Breeds – occasionally “cured” by treatment. SEASONAL FLANK ALOPECIA Edmund J. Rosser Jr., DVM, Diplomate ACVD Professor and Head of Dermatology Department of Small Animal Clinical Sciences Michigan State University, College of Veterinary Medicine ETIOLOGY Unknown - Change in photoperiod important. Role of pineal gland controlled hormones – Prolactin and Melatonin – normally increases with a decrease in photo-period. Localized hair follicle hormone receptor abnormality. SEX PREDISPOSITION Most frequently reported in spayed females. Can occur in intact males or females and neutered males. BREED PREDISPOSITION Boxers, Airedale Terriers, Bulldogs, Giant and Miniature Schnauzers, Bouvier de Flanders, Doberman Pinschers, Scottish Terriers, German Wirehaired Pointers CLINICAL FEATURES Bilaterally symmetrical alopecia with hyperpigmentation; Affects primarily the flank region; May extend to the lateral thorax or dorsally Most commonly occurs in fall/early winter and resolves in late spring/early summer; Cyclical pattern may vary. DIAGNOSIS History and physical exam Rule out other endocrine skin diseases – Hypothyroidism, Cushing’s Disease, Reproductive hormone imbalances, So –called “Alopecia-X” Histopathology - Follicular atrophy, keratin plugging, comedone formation; “Witches-foot” appearance; Hypermelanosis. TREATMENT Manipulation of photoperiod Use of exogenous prolactin or melatonin - Melatonin – 1-6 mg/dog TID for the duration of the Alopecic cycle. Needs to be started prior to the onset of alopecia.