Western Canada Veterinary Dermatology Information Newsletter

Volume 1 Issue 4 Fall 2008Compiled by Kinga Gortel, DVM, MS, Dipl. ACVD and Vincent Defalque, Dr. med.vet., Dipl. ACVDWe hope that you enjoyed a great summer! Ours was fun but not as relaxing as one might hope. Vincent moved into a new home and took his parents on a tour of western Canada. I adopted Barley, a lovable but high-maintenance Lab mix. Between moving, family visits, and obedience classes, the summer seemed to fly by.

In this issue, we hope to share some websites we visit, our referral information, and an update on house dust mites and storage mites from the Veterinary Dermatology journal.

We continue to welcome your referrals at the following practice locations:

Vincent Defalque Kinga Gortel

Canada West Veterinary Specialists & Critical Care Hospital

Westbank Animal Care Hospital C.A.R.E. (Calgary Animal Referral & Emergency) Centre

Phone: 604 473 4882 Phone: 250 768 4688 Phone: 403 520 8387

FAX: 604 473 4898 FAX: 250 768 9731 FAX: 403 692 4350

1988 Kootenay StreetVancouver BC V5M 4Y3

2429 Drought RoadWestbank BC V4T 1P7

7140 12th Street SECalgary AB T2H 2Y4

www.accg.com www.westbankanimalcare.vetsuite.com www.carecentre.ca

Western Canada Veterinary Dermatology Information Newsletter

W E B S I T E S W E L I K E . . .www.carecentre.caYou will find archived (color!) copies of this newsletter by clicking on Veterinary Community → News → West-ern Canada Veterinary Dermatology Information Newsletter. No need to search for those lost back issues...www.acvd.orgThe newly updated website of the American College of Veterinary Dermatology features a handy Find a Derma-tologist link. Snowbird clients can locate a dermatologist before heading south.www.vetmed.wsu.edu/depts-vcplThe WSU Veterinary Clinical Pharmacology website features great information about the MDR1 mutation, which imparts drug sensitivity to dogs (e.g. ivermectin). Information about affected breeds (approximately 3/4 of US Col-lies have a mutant gene), testing, and drugs to be avoided in affected dogs.www.greerlabs.comCan’t tell pigweed from plantain? Greer’s Botanical Information Sheets feature photos and descriptions of common allergenic plants. www.heska.com/allercept/client_info.aspPrintable client PDFs pertaining to the control of house dust mites, storage mites, molds, and other common al-lergens.www.grassmere-animal-hospital.com/greyhounds.htmThese folks know their greyhounds. Bald thighs? Sloughing nails? Footpad corns? An excellent resource for the unique “Greyhound things” affecting the skin, and a guide to how a Greyhound’s labwork is different.www.histiocytosis.ucdavis.eduA comprehensive, vet- and client-friendly site by the authority in the confusing world of histiocytic diseases, Dr. Peter Moore. www.vin.com How did we ever find information before VIN?

How long does my itchy patient have to stop medications before a dermatology referral?One of the most common questions referring veterinarians ask is “How long does my patient have to be off medi-cations before seeing you?” The simple answer is: not at all. We can arrange for any appropriate withdrawal times, if needed, at the time of the consultation. Allergy testing can then be scheduled at the most appropriate time of year for the pet. In steroid-dependent patients, we can try to manage pruritus with antimicrobials, bathing, cyclosporine, and other means that do not interfere with allergy testing. It is not necessary to stop steroids or anti-histamines in patients who do poorly without them. Withdrawal of bathing IS very useful - at least 5 days before the appointment to allow us to identify primary lesions, and to collect representative cytology samples.

These withdrawal times can also be found on Vincent’s handout at: www.accg.com//sites/accg/files/Dermatology/YourPetandSkinTesting.pdf

Western Canada Veterinary Dermatology Information Newsletter

Drug Withdrawal Times for Intradermal Allergy TestingOral steroids: 1 monthTopical steroids: 1 month preferred, minimum 10 daysInjectable long acting steroids: 6 weeks to 3 monthsAntihistamines: 10 daysFatty acid supplements: prefer 10 daysOther:Cyclosporine (Atopica): no withdrawal requiredAcepromazine: interferes with testing so not recommended as a sedative for travel

MORE THAN YOU EVER WANTED TO KNOW ABOUT HOUSE DUST MITES AND STORAGE MITESAllergy testing in human and veterinary patients has traditionally included the two house dust mites, Der-matophagoides pteronyssinus and Dermatophagoides farinae. More recently, many serum and skin allergy tests have included the prehistoric-sounding storage mites: Tyrophagus putrescensiae, Acarus siro, and/or Lepidoglyphus destructor. What are these mites and why are they important?

House dust mites are ubiquitous and found at highest concentrations in bedding, carpets, sofas, and pet beds. They feed on human and animal dander and produce large amounts of allergenic feces. Storage mites (sometimes also called forage mites) live on various food sources, most notably on dry grains, stored dry foods, and mould.

The two species of house dust mites are important and very common sources of allergens responsible for the sensitization of dogs with atopic dermatitis. Approxi-mately 50-60% of dogs reacting on allergy testing show positive reactions to these mites. Positive serum or skin allergy test reactions to storage mites are also common, and in our experience, often found in asso-ciation with house dust mite reactions. What remains poorly understood is the true role of the storage mites in a clinical setting. In humans, they are a cause of al-lergic symptoms due to occupational exposure in farms, grain stores, and bakeries, and can cause se-vere allergic reactions after ingestion of contaminated foods. Less is known in allergic pets. Are these mites truly present in the patient’s environment in sufficient

quantities to cause symptoms, or are they simply cross-reacting with the more ubiquitous house dust mites? Several recent studies have added to what we known about these mysterious mites.

Saridomichelakis et al’s Assessment of cross-reactivity among five species of house dust and storage mites in the April 2008 Vet. Derm. showed extensive co-sensitization to house dust and storage mites. Both naturally atopic dogs, and dogs experimen-tally sensitized to D. farinae showed ≥50% co-sensitization the various species of mites studied.

Another recent (Vet. Derm. August 2008) paper, Evaluation of storage mite contamination of com-mercial dry dog food by Brazis et al assessed 10 dif-ferent dry premium dog food bags in Europe. Prior studies in Germany and the northern US had failed to show storage mite contamination in dog food. This study showed a different story. It was the first report to demonstrate that low numbers of storage mites could be found in some unopened bags of food. When the dog food bags were stored open for 6 weeks in a labo-ratory setting, no contamination was seen. However, almost all bags stored in a kennel setting became con-taminated by 3 to 5 weeks. The most common culprit was the mould storage mite, Tyrophagus spp. Interest-ingly, the one bag with an airtight closure did not show contamination. This study suggests that dry dog food may represent a relevant source of storage mite expo-sure, but further investigation is needed to assess dog foods in household settings.

Recommendations for controlling house dust mites in the home environment are easily found, and we rec-ommend checking Heska’s website listed on the previ-ous page. It is more difficult to assess whether control measures for storage mites are necessary, but in dogs who react to storage mite allergens, consideration should be given to the following:

• store food in airtight container in a dry area• if possible, freeze dry food and thaw enough for 1-2

days at a time• buy small bags of dog food, do not stockpile large

amounts• never use outdated food• consider a trial period (1-2 months) of feeding only

canned food or a grain-free home cooked diet• check for and remove any mould in the home• wash food containers in hot water• do not store dog food with other dry foods, fruit, or

vegetables• use the same precautions for treats and supplements

Western Canada Veterinary Dermatology Information Newsletter

Calendar of dermatology eventsOkanagan Veterinary Medical Association: Tuesday October 28, 2008 Kelowna, BCMistakes and Misconceptions in Veterinary Dermatology - 2 hr - Kinga Gortel

Canada West Veterinary Specialists and Novartis Animal Health: Thursday October 23, 2008 Vancouver, BCThe Use of Cyclosporine for the Treatment of Atopic Dermatitis - 1.5 hr - Vincent Defalque

George F. Muller Veterinary Dermatology Seminar: October 29-November 5, 2008 Big Island, Hawaiiwww.vetmed.ucdavis.edu/CE/mullerderm.htmlThe theme of this year's program is "Voting for Success: Electing the Best Candidates for Therapy!" Best available therapy will be emphasized along with the latest information on many skin diseases seen commonly in general and referral practice.

6th World Congress of Veterinary Dermatology: November 19-22, 2008 Hong Kongwww.vetdermhongkong.comThis amazing meeting takes place in a different part of the world every 4 years and features content from various international experts. Sampling the local culture is a highlight of the World Congress.

Nestle Purina Petcare: Sunday March 1, 2009 Saanich, BCFood Allergy in Dogs and Cats - 1.25 hr - Vincent Defalque

Calgary Academy of Veterinary Medicine: March 11, 2009 Calgary, AlbertaMistakes and Misconceptions in Veterinary Dermatology - 2 hr - Kinga Gortel

North American Veterinary Dermatology Forum: April 15-18, 2009 Savannah, Georgiawww.navdf.orgThe annual meeting of the American College of Veterinary Dermatology and the American and Canadian Academies of Veterinary Dermatology. This well-attended meeting provides specialists and practitioners with an interest in dermatology with a wealth of information. Sci-entific sessions are presented alongside practical concurrent sessions.

Veterinary Dermatology Information Newsletterc/o Dr.Vincent DefalqueCanada West Veterinary Specialists1988 Kootenay StreetVancouver, BC V5M 4Y3

Western Canada Veterinary Dermatology Information Newsletter