Apollo is a 9 year old Shih Tzu with a long history of pruritus, hair loss and a greasy, smelly coat and skin. He began with scratching toward his neck and chest as a 4 year old dog. Pruritus worsened over several months to include the groin and then all four legs with scratching and chewing followed by crust and odor. Over the last few years treatments have included steroid injections (Vetalog/kenalog), oral cortisone medications and occasionally oral antibiotics and antifungals. Steroid injections have helped in the past but for only 7-10 days. Apollo was also on Atopica (combined with ketoconazole) at one point. This regimen seemed to help but made him feel poorly over time so it was discontinued. At the time of presentation he had also been on Apoquel for 2 weeks but with no progress to date. Culture of the skin had been performed 2 weeks prior to our initial exam and yielded methicillin sensitive Staphylococus pseudintermedius and methicillin resistant Staphylococcus schleiferi. Clindamycin was prescribed at 12 mg/kg PO qd.
At our initial exam Apollo was a very greasy and smelly dog with total body seborrhea and widespread erythema. Pruritus at this time was rated 8 out of 10. More severe honey colored crust and diffuse erythema were present in intertriginous areas including the paws, axillae, ventral neck, groin and medial thighs/rear legs. Many of these areas were also lichenified and alopecic. Samples were obtained for impression smear cytology from most of these areas. Under 100x (oil immersion) magnification, samples from the neck, axillae, face folds and paws had occasional cocci but also had large numbers of yeast consistent with Malassezia spp. (see Figure 1)
Differential diagnoses at that time included primarily allergic disease (especially Atopic dermatitis, food allergy), but also metabolic disease that may predispose to secondary infections. Bloodwork was performed – including CBC/CHem/Thyroid profile (FT4/TSH) and was normal. A modified treatment plan included continuing clindamycin but changed to BID – using the 75 mg capsules (8 mg/kg) and fluconazole was added at 10mg/kg PO once daily. Topical therapy was emphasized consisting of MiconaHex Triz shampoo (Dechra Veterinary Products – 2% miconazole, 2% chlorhexidine + TrizEDTA) used for bathing weekly and MiconaHex Triz Spray applied to problems areas such as groin, neck and paws, daily between baths.
At a recheck examination 3 weeks later, Apollo was improved but still pruritic and rated 6/10. Skin lesions, crust and erythema had improved but only slightly. Recheck of impression smear cytology found minimal bacteria but still significant number of yeast consistent with Malassezia. At this time medications were changed to ITRAconaozle at 10 mg/kg PO once daily and bathing increased to 2-3 times per week with antibacterial/antifungal spray continued daily.
Upon follow up with the owner by phone 10 days later, she reported that Apollo was much less red and greasy and pruritus had decreased to ~2/10.
Apollo was eventually diagnosed with atopic dermatitis. However, at the time of initial presentation his primary problem was generalized secondary Malassezia dermatitis. Malassezia, a common opportunistic yeast, may cause odor, honey colored crust and in some cases intense pruritus when present on the skin. Intradermal allergy tests now often include tests for Malassezia hypersensitivity and may be a significant part of the pruritus associated with atopic dermatitis. Breeds such as Basset hounds and the Shih Tzu described here have been shown to be predisposed to Malassezia dermatitis. Triazole antifungals including fluconazole, ketoconazole and itraconazole are often successful in management of Malassezia. On occasion, however some cases can be quite refractory, requiring higher doses along with aggressive topical antifungal therapy. Evaluation of surface cytology, via direct impression smear or tape prep is critical in diagnosis and monitoring of progress in cases of Malassezia dermatitis. As is commonly seen, antipruritic/anti-allergy drugs including steroids, Atopica and Apoquel are often minimally effective in the face of significant infection. Once the Malassezia is resolved, however, these drugs may become quite effective or may often be used a lower doses. Any dog presented for pruritus with any evidence of erythema, crust, seborrhea or papular dermatitis should always be evaluated cytologically in order to identify and manage secondary complications such as Malassezia or bacteria. It is also important to note that while a methicillin resistant Staphyloccal infection was noted initially in this case, it resolved with antibiotics fairly quickly, leaving the yeast dermatitis as a cause of ongoing pruritus, inflammation and crust. This was further illustration of the often dynamic environment of the skin of allergic dogs warranting regular re-evaluation and reassessment.
Dr. Joel Griffies is a 1992 graduate of Auburn University’s College of Veterinary Medicine. After graduation he worked in a mixed large/small animal practice and small animal emergency practice in Georgia. In 1994 he opened a small animal practice in Lawrenceville, GA where he worked for 5 years before pursuing his dermatology career. In 1999 he relocated to southern California to begin a residency with Animal Dermatology Clinic. Dr. Griffies completed his residency in 2001 and became a shareholder of Animal Dermatology Clinic shortly thereafter. Dr. Griffies is a diplomate of the American College of Veterinary Dermatology (ACVD) and co-owner of Animal Dermatology Clinics of Tustin, Marina del Rey, Pasadena and Upland, CA, Marietta, GA, Louisville, KY and Indianapolis, IN. He is also a member of the executive board for Animal Dermatology Clinic Management Group.
Dr. Griffies is married, has 2 children and a high energy Border terrier named Grady to keep him busy.
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