Scaling and flaking arises when there is either excessive production of
keratinocytes with a high rate of loss from the superficial layers of the
skin, or when there is a degree of epidermal separation. In the former
case, continued trauma is a common cause of localised scaling, such as
might arise from repeated tack or harness rubbing. Many keratin disorders,
including some important immune-mediated skin diseases, are characterised
by excessive flaking and scaling. A few will have concurrent, wet dermatosis
with crusting if the pathology is sufficiently deep. Flaking and scaling can
be differentiated relatively easily from crusting and this is an important
concept in dermatological diagnosis.
