Veterinary Medicine - May 2008 - (Page 272) Cyclosporine PEER-REVIEWED 3. The same cat as in Figures 1 & 2 six weeks after beginning cyclosporine therapy. Note the resolution of the lesions around the mouth. The lesion near the ear had resolved as well. The cat was no longer traumatizing itself. 4. Perianal fistula in a dog. Note the swelling and the multiple draining fistulous tracts. gastrointestinal effects, especially during the induction phase, if the dog or cat cannot tolerate the drug on an empty stomach. In our practice, serum concentrations of cyclosporine are not routinely monitored; improvement in clinical signs (pruritus) is the most important measurement of ef cacy (Figure 3). If the pet does not respond to therapy, then serum concentrations of the drug are monitored to ensure that adequate absorption is occurring. When necessary, cyclosporine concentrations should be checked just before administering a dose in order to obtain trough serum concentrations (12 hours if administering twice daily, or 24 hours if administering once daily). The serum cyclosporine concentration should be between 200 to 500 ng/ml; however, we usually recommend concentrations closer to 200 ng/ml. Sebaceous adenitis Sebaceous adenitis, a skin disease with an unknown cause that is uncommon in dogs and rare in cats, is characterized by in ammatory destruction of the sebaceous glands. A strong breed predilection for standard poodles exists, but sebaceous adenitis has been diagnosed in many breeds. As the disease progresses, dogs develop scaling, follicular casts, and hair loss characterized by broken, dry, dull hairs in a symmetrical pattern. Dogs are susceptible to secondary bacterial infections or colonization of the skin with bacteria and yeast. Cats show multifocal, annular areas of alopecia with scaling and crusting. Successful treatment (resolution of clinical signs) of sebaceous adenitis was rst reported in 1991 in one dog receiving unmodi ed cyclosporine.14 In a 2005 study, 12 dogs with sebaceous adenitis were treated with cyclosporine at 5 mg/kg once daily for 12 months and were evaluated at four-month intervals.15 After four months of treatment, the dogs showed marked clinical improvement that continued throughout the study. Histologically, decreased in ammation and an increase in the number of hair follicles with sebaceous glands, suggesting gland regeneration, occurred with continued treatment. Continued treatment was needed as clinical signs recurred if cyclosporine was discontinued. Two cats with sebaceous adenitis have also responded to treatment.16 Inform clients that sebaceous adenitis is not curable. Nonetheless, using cyclosporine as an adjuvant therapy may be markedly bene cial for affected animals and their owners. The following is a treatment protocol for sebaceous adenitis: • Treat concurrent bacterial and yeast infections with appropriate antibiotics and antifungal medications (preferably based on culture and sensitivity results; empirically, however, we generally recommend 22 to 30 mg/kg cephalexin orally twice daily and 5 to 10 mg/kg ketoconazole orally once daily initially) for at least 30 days. • Conduct a cyclosporine trial (5 mg/kg orally once daily) for four months. • The owner should bathe the dog with antiseborrheic (e.g. containing sulfur and salicylic acid) and emollient (e.g. containing lanolin or essential fatty acids) shampoos as needed to control odor, crusting, and scaling (one to three times a week). • If the dog shows improvement at the end of the trial, continue oral cyclosporine therapy. In addition, administering ketoconazole to decrease the total dose of cyclosporine and to control Malassezia species overgrowth can be considered. It is unknown whether alternate-day cyclosporine therapy is equally effective as daily therapy. The owner should also continue bathing the dog as needed. Canine perianal fistula Canine perianal stula is a chronic, painful skin disease involving the anal and perianal tissues (Figure 4). The skin is ulcerative, and retrocutaneous stulas ( stulas extending behind the cutaneous zone of the anus) are typical. Dogs present with tenesmus, dyschezia, constipation, 272 May 2008 VETERINARY MEDICINE
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