Epidermal architecture that depends on turnover time.

The concept of epidermal architecture that depends on epidermal turnover time is described. The epidermal architecture is determined, not by a simple proliferative condition, but rather by an epidermal turnover time (that depends both on cell number as well as on the proliferative condition). This is in relation to 'keratinization process' that requires a definite time to be completed. Using the concept, hyperproliferative 'psoriasiform' epidermis and hypoproliferative 'atrophic' epidermis are naturally described.