Transepidermal water loss and absorption of hydrocortisone in widespread dermatitis.

Percutaneous absorption of hydrocortisone was measured in three children and six adults with widespread dermatitis, after the application of 1% hydrocortisone cream. Before application of the cream, the transepidermal water loss (TEWL) was measured on six skin areas. A highly significant correlation was found between the post-application rise in plasma cortisol level and the mean transepidermal water loss. Thus, measurement of TEWL affords a simple, non-invasive method for assessing the systemic effect of hydrocortisone applied to widespread dermatitis.