Topical triamcinolone and allergic dermatitis: A case study


Topical triamcinolone and allergic dermatitis: A case study

Figure 1A. Inguinal region: papular dermatitis due to bacterial folliculitis.
Galaxy, a 7-year-old intact male golden retriever, was presented on referral for evaluation of nonseasonal pruritus of four years' duration involving the feet, axillae,3ww ventral abdomen, and tailhead. The referring veterinarian had made a presumptive diagnosis of flea allergy dermatitis and had instituted flea control with fipronil, which alleviated the tailhead pruritus, as well as oral corticosteroid therapy, which was initially successful at controlling the remaining pruritus. However, during the previous year, prednisolone at a dose of 0.5 to 1 mg/kg orally daily had less effectively controlled the dog's clinical signs—the pruritus had intensified and the overall condition of the skin had worsened. In addition, Galaxy had developed polyuria, polydipsia, and a thin haircoat. The corticosteroid therapy was discontinued one week before presentation.

Figure 1B. Pododermatitis: erythema, lichenification, and excoriations.
At referral, the owner reported that Galaxy was demonstrating moderate pruritus involving the inguinal area, feet, ears, dorsum, and flanks. Dermatologic examination showed a generalized papular to pustular dermatitis (Figure 1A), epidermal collarettes, a moderate to severe erythematous pododermatitis with excoriations and lichenification on all four feet (Figure 1B), hypotrichosis and inflammatory scaling on the trunk and tailhead (Figure 1C), and mild erythema and hyperpigmentation in the axillary and inguinal regions. The otic examination revealed bilateral ceruminous otitis externa with mild canal erythema and edema. No fleas or flea dirt was detected. The remaining physical examination findings were within normal limits.

Differential diagnoses and primary workup

Figure 1C. Galaxy's dorsum: diffuse hypotrichosis and inflammatory scaling.
The differential diagnoses at this time included iatrogenic hyperadrenocorticism, flea allergy dermatitis (Galaxy's flea control had not been consistent), food allergy, atopic dermatitis, allergic otitis externa, secondary bacterial folliculitis, secondary Malassezia dermatitis, demodicosis, dermatophytosis, cheyletiellosis, and sarcoptic mange.

The initial workup included deep and superficial skin scrapings from multiple sites, fungal culture from affected abdominal skin, a complete blood count (CBC), serum chemistry profile, urinalysis, urine culture, serology for Sarcoptes antibodies, skin cytology from papules and pustules, and ear swab cytology.

Figure 1D. Skin cytology from the inguinal area: inflammation with intracellular and extracellular cocci.
Cytologic examination results showed numerous yeast consistent with Malassezia pododermatitis, neutrophilic dermatitis with intracellular cocci suggestive of bacterial folliculitis involving the inguinal region and dorsum (Figure 1D), and increased numbers of keratinocytes associated with numerous organisms consistent with Malassezia otitis (Figure 1E). The CBC, serum chemistry profile and urinalysis results were consistent with iatrogenic hyperadrenocorticism (moderately increased ALP and ALT activities and a urine specific gravity of 1.015); the urine culture was sterile. All other test results were within normal limits.