Hyperkeratosis is first of all an adaptive physiological phenomenon that aims, through the accelerated production of strongly keratinised cells, to strengthen the resistance of the epidermis. Walking barefoot or intense manual work generates a “ reflex ” –a thickening of the soles of the feet and palms of the hands. This phenomenon has a beneficial protective effect but creates discomfort on the surface of the skin, which becomes rough, course and prone to cracking.
If the physical stress is localised (repeated rubbing, permanent pressure on a very particular area), the hyperkeratosis takes on the appearance of a callus. The most common example is a plantar callus, caused by high stress on a small area of skin, causing a painful phenomenon similar to when a foreign body comes into contact with the foot.
Out of all dermatological conditions, it is psoriasis which almost constantly induces hyperkeratotic areas. The typical plaques of the condition, originally red, are surrounded by thick, very dense skin flakes, creating a scaly appearance. A kind of armour forms, causing significant aesthetic damage, skin discomfort and preventing psoriasis medications from penetrating.