Veterinary Medicine - August 2008 - (Page 460)

Demodicosis PEER-REVIEWED Negative cytologic examination results from skin scrapings do not de nitively rule out D. gatoi infection. Empirical therapy for D. gatoi infection is sometimes administered to pruritic cats to rule out demodicosis before pursuing additional testing for pruritic diseases or diagnosing psychogenic alopecia. TREATING FELINE DEMODICOSIS Feline demodicosis is less prevalent than canine demodicosis. Hence, less information is available regarding treatment. Treatment includes correcting any underlying disease as well as miticidal therapy. Lime sulfur dips are the safest option and have been used at 1.6% to 2% every ve to seven days for four to six or more weeks in cats infested with D. gatoi and D. cati.10 Lime sulfur dips can also be used on pruritic cats suspected to have D. gatoi infection. The higher concentration is more effective in eliminating these mites. Patient tolerance is enhanced by using a pumpup garden sprayer for application. Use lime sulfur on all in-contact cats when faced with D. gatoi infection, as this mite is potentially contagious to other felids.12,37 Using an Elizabethan collar is recommended until the product dries to prevent oral ingestion. Although 0.0125% to 0.025% amitraz applied twice weekly to every other week is effective in treating infections with both species of feline demodectic mites,39 we do not recommend its routine use given other alternatives and the risk of toxicosis. Topical organophosphates were reported to be effective in treating infections with both mites,40 but these chemicals are not recommended since safer alternatives are available. No side effects were seen when three cats with D. cati infection were treated with doramectin (600 µg/kg subcutaneously weekly) for no more than three injections.31 This treatment resolved the demodicosis. Anecdotally, ivermectin given orally at 300 to 600 µg/kg daily to every other day has been used to treat feline demodicosis. Ivermectin formulations containing the least amount of propylene glycol are recommended for cats. Because of the risk of neurotoxicosis41 and no perceived improved ef cacy when compared with lime sulfur, ivermectin use is discouraged. Weekly application of selamectin for six weeks did not eliminate D. cati or D. gatoi infections.42 We have not found the topical application of pronil to be effective in controlling infestation with either mite. Demodectic otitis can be treated topically with a 0.01% solution of ivermectin (Acarexx—Idexx) or a 0.1% solution of milbemycin oxime (MilbeMite Otic Solution), but they are not labeled for this use. and using proper sampling techniques. Treatment failure is rarely due to resistant mites. More frequent causes of treatment failure include poor pyoderma control, premature discontinuation of therapy, unsuccessful control of underlying conditions, and the use of immunosuppressants such as glucocorticoids. Amitraz, ivermectin, and milbemycin oxime are recommended for treating canine demodicosis. Lime sulfur, especially, and ivermectin are recommended to treat feline demodicosis. REFERENCES 1. Desch CE, Hillier A. Demodex injai: a new species of hair follicle mite (Acari: Demodecidae) from the domestic dog (Canidae). J Med Entomol 2003;40(2):146-149. 2. Bensignor E, Guaguere E, Prelaud P. Demodicosis due to Demodex injai in dogs: eight cases. Vet Dermatol 2006;17(5):356-357. 3. Hillier A, Desch CE. Large-bodied Demodex mite infestation in 4 dogs. J Am Vet Med Assoc 2002;220(5):623-627. 4. Chesney CJ. Short form of Demodex species mite in the dog: occurrence and measurements. J Small Anim Pract 1999;40(2):58-61. 5. Tamura Y, Kawamura Y, Inoue I, et al. Scanning electron microscopy description of a new species of Demodex canis spp. Vet Dermatol 2001;12(5):275-278. 6. Robson DC, Burton GG, Bassett R, et al. Eight cases of demodicosis caused by a long-bodied Demodex species (19972002). Aust Vet Pract 2003;33(2):64-72. 7. Saridomichelakis MN, Koutinas AF, Farmaki R, et al. Relative sensitivity of hair pluckings and exudate microscopy for the diagnosis of canine demodicosis. Vet Dermatol 2007;18(2):138-141. 8. Gortel K. Update on canine demodicosis. Vet Clin North Am Small Anim Pract 2006;36(1):229-241. 9. Scott DW, Miller WH, Grif n CE. Dermatologic therapy. In: Mueller and Kirk’s small animal dermatology. 6th ed. Philadelphia, Pa: WB Saunders, 2001;207-273. 10. Mueller RS. Treatment protocols for demodicosis: an evidence based-review. Vet Dermatol 2004;15(2):75-89. 11. Kwochka KW, Kunkle GA, O’Neill Foil C. The ef cacy of amitraz for generalized demodicosis in dogs: a study of two concentrations and frequencies of application. Compend Contin Educ Pract Vet 1985;7:8-17. 12. Scott DW, Miller WH, Grif n CE. Parasitic skin diseases. Mueller and Kirk’s small animal dermatology. 6th ed. Philadelphia, Pa: WB Saunders, 2001;423-516. 13. Hugnet C, Buronfosse F, Pineau X, et al. Toxicity and kinetics of amitraz in dogs. Am J Vet Res 1996;57(10):1506-1510. 14. Hugnet C, Bruchon-Hugnet C, Royer H, et al. Ef cacy of 1.25% amitraz solution in the treatment of generalized demodicosis (eight cases) and sarcoptic mange ( ve cases) in dogs. Vet Dermatol 2001;12(2): 89-92. 15. Avsarogullari L, Ikizceli I, Sungur M, et al. Acute amitraz poisoning in adults: clinical features, laboratory ndings, and management. Clin Toxicol (Phila) 2006;44(1):19-23. 16. Fourie LJ, Kok DJ, du Plessis A, et al. Ef cacy of a novel formulation of meta umizone plus amitraz for the treatment of demodectic mange in dogs. Vet Parasitol 2007;150(3):268-274. 17. Macdonald N, Gledhill A. Potential impact of ABCB1 (p-glycoprotein) polymorphisms on avermectin toxicity in humans. Arch Toxicol 2007;81(8):553-563. 18. Kenny PJ, Vernau KM, Puschner B, et al. Retinopathy associated with ivermectin toxicosis in two dogs. J Am Vet Med Assoc 2008;233(2):279-284. 19. Mueller RS, Bettenay SV. A proposed new therapeutic protocol for the treatment of canine mange with ivermectin. J Am Anim Hosp Assoc 1999;35(1):77-80. 20. Paul AJ, Tranquilli WJ, Seward RL, et al. Clinical observations in collies given ivermectin orally. Am J Vet Res 1987;48(4):684-685. 21. Hopper K, Aldrich J, Haskins SC. Ivermectin toxicity in 17 CONCLUSION Canine and feline demodicosis are dermatologic conditions that you can diagnose by recognizing the clinical signs 460 August 2008 VETERINARY MEDICINE http://www.stokespharmacy.com http://www.stokespharmacy.com

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Veterinary Medicine - August 2008 Contents Editors' Note Leading Off ClinQuiz Idea Exchange Practical Matters Diagnosing and Treating Canine Copper-Associated Hepatopathies Canine and Feline Demodicosis CE Form Advertiser Index Product Preview Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - August 2008

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