Normal turnover rate of epidermis:
Epidermal turnover time - skin doubling time -Time taken by keratinocytes to move from Stratum Basale to environment. -Around 14 days are required to move from Stratum Basale to reach lowermost layer of Stratum Corneum & 14 days to cross Stratum Corneum. -Sloughing off requires 28 days So total ETT =56 days (8 weeks) The turnover time in psoriasis = 4 days.
2 weeks
4 weeks
6 weeks
8 weeks
Layers of epidermis, dermis