Effects of dermatitis, stripping, and steroids on the morphology of corneocytes. A new bioassay.

This study was designed to investigate the effects of increased or decreased epidermal turnover on the morphology of human corneocytes. The desquamating portion of the stratum corneum was sampled with the detergent scrub technique using Triton X-100. The following parameters were measured: size (surface micron2), shape (regular, irregular), nuclear inclusions, trabeculae, and numerical counts. Specimens were obtained from adult males with allergic contact dermatitis (N=18); with tretinoin-induced dermatitis (N=11); after cellophane stripping (N=11); and after treatment of these conditions with topical steroids (N=40). Data from 250,000 cells were analyzed statistically. The reproducibility of the method is good (r=0.934). Corneocytes from skin of patients with allergic contact dermatitis differed from those of normal skin: they were 15% smaller and of irregular shape with asymmetrical trabeculae; 50% were nucleated and about 3 times as many cells were collected per cm2 skin surface. Tretinoin and stripping produced similar but more pronounced effects. Topical steroids significantly improved all parameters (p less 0.01). Betamethasone-17-dipropionate was more effective than the valerate. This bioassay permits sensitive measurements of corneocyte morphology in conditions with altered epidermal cellular kinetics. It provides a method to evaluate steroid effectiveness.