A 12-year-old male entire Miniature Pinscher presented with excoriations at various body sites, progressively forming ulcers and enlarging until arrested by treatment. Based on the clinical presentation and histopathological analyses, sterile neutrophilic dermatosis was suspected. Therefore, the dog was started on prednisolone. Marked improvement was achieved with prednisolone treatment, suggesting a diagnosis of pyoderma gangrenosum (PG). Transcription levels of cytokine mRNA in lesional skin before and after treatment from this dog were quantified by real-time RT-PCR. Transcription levels of tumor necrosis factor-α, interleukin (IL)-1β, IL-8 and IL-17A were higher in lesional skin before treatment than after treatment. Levels of various cytokines could be increased in lesional skin of dogs with PG as well as in human patients with PG.