There is no evidence cavemen had corns and even if they did, refined tools to shave the skin, No artifacts have never been found. Corns were known, in ancient Egypt (4000 BCE), and copper alloy razor like implements found which are likely to be used as corn scrappers. In the New Kingdom (1567-1320 BCE) bronze razors replaced the crude copper alloy. The coming of the Iron Age (1000 BCE) probably meant skin scraping utensils were made from iron.
By the time of the Greeks , no less a patron than Hippocrates (c. 460 BC- c. 370 BC) recognised the necessity to physically reduce hard skin followed by removal of the cause which was usually tight or ill-fitting shoes. He is thought to have invented the surgical scalpel for this purpose.
In the 2nd century Celsus, a Greek physician living in Rome was probably the first person to give corns their name. He called them clavus, because they resembled the conical shape of a carpenter’s nail. Later the medical term for a corn was "clavus pedum".
The use of pumice stone to rub away hard skin was popular among Roman Legions. Shoe finds from this time confirm foot problems, then, were no different to today.
Acceptance that treatment of hard skin required physical removal combined with re-hydration of the skin cells has not changed for centuries. In 1163 a papal decree, forbid clergy to commit sacrilege of shedding blood and blood letting monks turned their duties over to barbers and corn cutters. Apothecarists and magic-obsessed practitioners of the Middle Ages reveled in the means of skin hydration and came up with bazaar combinations ranging from pastes made from swine dung or the ash of the willow bark; to soaks of the gastric juice of a calf's stomach. Unusual choice maybe but there was method in their madness. Increasing skin temperature with a hot poultice would temporarily soothe pained nerve endings and increase the local water content of the skin cells. Desquamation (removal of old skin cells) is enhanced in the presence of water. This would make the hardened skin easier to remove and in some cases (rarely) allow complete separation of the corn from the skin surface. The chemical addition of the acidic calf’s stomach would further enhance skin cell separation by altering the pH of the skin which would increase the uptake of water within the skin cells themselves.
A common practice throughout history was to urinate on the corn to soften the skin. The acid mantle is a protective cover which surrounds the skin and helps its physiological function. Urea is featured within skin chemistry and adding small concentrations would promote exfoliation i.e. scaling of the skin. Chemical creams containing urea are now commonly used in the dermatological treatment of hyperkeratosis (excessively thick skin) and ichthyosis (severely scaling of the skin). N.B. Chemical exfoliants are not recommend for delicate skins and should be used only under the direction of a physician.
Corn salves were popular among corn cutters who thrived after the Quack Act. The presence of plague and syphilis sores was too great a challenge for traditional medicine and as a consequence it was decreed in England that anyone could treat superficial sores by any means and was not restricted to a physician. Prior to the Great Fire of London (1666) it was common place to advertise personal services such as the removal of corns through the medium of street cries. The term quack was taken to mean “shout,” and quacksalvers, thrived.
The street cry lyrics were pretty crude by modern jingle standards but often the melody was composed by celebrated musicians. Orlando Gibbons (1583-1625) was a prolific jingle writer at this time although he is better known for his madrigals and music for the Anglican Church. Gibbons eventually became the organist of the Chapel Royal, and was named virginals to the king, before becoming organist of Westminster Abbey. Gibbons never forgot his humble beginnings and composed "The cries of London" a poignant fantasia for voices and viols based on the traditional cries of London street peddlers.
It took until 1680 before an open razor was available and a half century later before cast steel (a harder, finger grained steel) which was able to take and hold an edge. When a tiny quantity of silver was added to the cast steel in 1820 this meant greater control of the cutting instrument could be achieved.
To date no one has really been able to explain why some people develop corns and others not. We know however corns do not have roots (a popular misunderstanding) and this accounts for why there is nothing in a bottle or tube able to get rid of them. The cells of the outer layers of skin increase their production when stimulated by external friction (heat) to the skin surface. This usually occurs by shearing stress and the culprit is often a tight shoe. In the beginning corns and callous are self-inflicted lesions. Research indicates people have an enzyme within their blood supply which biochemically controls skin cell production. When the skin is damaged, some people produce more skin cells than others. Hard skin can be found on weight bearing areas including the heel, ball of the foot and tops of the toes. Soft corns usually appear in between the toes. Hard and soft corns really describe the same concentration of skin with soft corns being saturated in sweat. Due to poor self-treatment, the composition of corns can vary with many incorporating blood vessels and some even trapping painful nerve endings.
Occasionally hormonal imbalance due to menopause changes can result in the formation of thick horny skin cells or ichthyosis (fish scales). These changes are sudden and occur overnight.
Fibrous corns present permanent changes to the skin which has become anchored to the bone beneath and bursitic corns occur on areas prone to heavy shearing stress. The prognosis for these skin lesions is very bad and although much relief can be gained by regular visits to the podiatrists - there are no cures.