Ultrasonographic evaluation of skin thickness in small breed dogs with hyperadrenocorticism.

The purpose of this study was to propose a standard of differentiation between normal dogs and patients with hyperadrenocorticism (HAC) by measuring the skin thickness using ultrasonography in small dogs. Significant changes in skin thickness of patients treated with prednisolone (PDS) or patients with HAC treated with trilostane were also evaluated. Skin thickness was retrospectively measured using three abdominal digital images obtained from small dog breeds weighing less than 15 kg undergoing abdominal ultrasonography. The mean skin thickness was 1.03 ± 0.25 mm (mean ± SD). Both the HAC and PDS groups showed significantly thinner skin than the normal group. Seven of the 10 HAC patients treated with trilostane had increased skin thickness. The value of AUC was 0.807 based on the ROC curve test differentiating between normal dogs and HAC patients. Sensitivity was 76% and specificity was 73% when the skin thickness was less than 0.83 mm as cutoff value. In conclusion, measurement of skin thickness in small dog breeds using ultrasonography is likely to provide clinical information to differentiate HAC patients from normal dogs. However, exposure to PDS, trilostane and other conditions also may have a significant effect on skin thickness.