Congenital non-bullous ichthyosiform erythroderma-cell kinetics before and after treatment with etretinate

Cell birth‐rates and the labelling index (LI) were measured in a patient with congenital nonbullous ichthyosiform erythroderma (CIE). Measurements were made before and after a course of oral etretinate. The cell birth‐rate, following treatment, was less than half of the pretreatment rate. The LI showed little change. The therapeutic effects of oral etretinate may be, to some extent, due to a suppression of cell renewal. The fact that the LI was unchanged when cell production was reduced indicates that the LI alone is an unreliable indicator of proliferative activity.