Transepidermal water loss in healthy and atopic dogs, treated and untreated: a comparative preliminary study

An impaired skin barrier function is thought to be crucial for allergic sensitization. In humans, the skin barrier is assessed by noninvasive methods, such as the measurement of transepidermal water loss (TEWL). Although limitations have been reported, measurement of TEWL has been demonstrated to be a suitable method to assess barrier function indirectly in dogs. The purposes of this prospective clinical study were twofold. The first aim was to evaluate and compare TEWL in healthy and atopic dogs. The second aim was to evaluate TEWL in a population of atopic dogs and to assess TEWL in dogs whose disease was in remission after successful therapy and compare it with dogs whose disease was not controlled or receiving treatment. One hundred and fifty dogs were selected and divided into the following three groups: 50 atopic dogs before specific treatment (group A); 50 in remission (group B); and 50 control dogs (group C). The mean values for TEWL for each group were 22.47 (g/m(2) h) (group A; 95% confidence interval 20.85-24.09), 12.57 (g/m(2) h) (group B; 95% confidence interval 11.43-13.7) and 8.81 (g/m(2) h) (group C; 95% confidence interval 8.09-9.52); P-value was 0.0001 for TEWL (groups A, B and C). This study showed a significant difference of TEWL between healthy control dogs and dogs with atopic dermatitis. Additionally, TEWL was lower in atopic dogs whose disease was in remission due to treatment. These results were consistent with reports in human medicine about TEWL.