Routes of ionic permeability through mammalian skin

The skin's highly resistive nature to the transport of ions and neutral compounds is primarily due to the lipids of the stratum corneum. The skin also contains a number of appendageal structures such as hair follicles and sweat ducts which can serve as shunt pathways for ion transport. Evidence is presented to suggest that ion transport can occur via the extracellular lipid domains of the stratum corneum through interfacial defects present at sites of lipid phase separation. Moreover, a similar mechanism of transport has been hypothesized for other lipid membranes.