The present invention concerns a method for evaluating the epidermal homeostasis of the skin of a subject, comprising differential analysis of the expression of a gene, preferably of two genes, selected from the group of genes consisting of KRT6B, KRT16, ESRRA, CBX3, MAP3K5, TRIO, PIK3CD, TCRB, PRRG2, ICP22BP, GPX3, GBA, BPGM, NID1, SMT3H2, LGALS2, DOC1, PRKCG, S100A8, S100A9, S100A2, S100A7, K15, SPRR1B and GSN in response to a physical or chemical challenge of the stratum corneum. It also concerns various methods for diagnosing the state of the epidermis of an individual and methods for detecting and screening products or procedures which can improve epidermal homeostasis. The invention also pertains to kits and arrays which can be used in these various methods and processes.