They grow, but they're dead. They protect, but they can hurt. They're ugly, but necessary. They're calluses.

They're What?

Calluses are flat pads of dead skin that grow in response to frequent pressure and friction, usually on the hands and feet. Generally painless, they protect the tissue underneath from stress and wear.

There is a type of callus known as a corn, which is a thick lump of dead skin, usually with a central kernel, that grows due to uneven pressure. These tend to appear over a joint, often on the toes, and can be painful. Corns are sometimes called clavi.

Old people have less fatty tissue and elasticity in their skin, which makes it more sensitive. Thus, the elderly develop calluses more often. That is why the grumpy old woman in any given children's novel is always complaining about her corns.

What They Are Not

Often, when sharp pressure is exerted, blisters will precede the development of calluses. These are a thickened layer of skin usually covering a liquid bump. Calluses don't have any moisture underneath them. Blisters peel off rapidly. Calluses do not. Blisters are quite ugly. Flat calluses blend into the skin and aren't noticeable unless you're looking for them. (Corns don't, and are even uglier than blisters.)

The History

Calluses don't have much more history than any other part of the body, but they’ve been with humanity throughout history and contributed to the general welfare. For example, string instruments have been around for ages, and as any guitarist, violinist or cellist knows, calluses are essential if you want to play for more than a few minutes. Many sports encourage the development of calluses, from the age-old golf to the more modern parkour. But for a great deal of recent history, calluses were best noted by their absence.

Until the recent demise of the leisure class, society was divided between those who had to do physical labour to earn a living, and those who didn't. Those who didn't were extremely proud of the way they arranged things (usually mooching taxes and rent off the workers), and called themselves gentlemen. One of the signs of a gentleman - besides a university education and expensive wardrobe - was smooth and uncallused hands—evidence that physical labour was not part of his lifestyle.

Before the invention of modern cushioning footwear, corns on the feet were painfully common. Physicians of the Middle Ages and Renaissance felt that cutting corns was beneath their dignity, so the task was relegated to those willing to do the dirty work - like tooth pullers. By the early 17th Century, corn-cutting was a street trade like knife-sharpening and by the late 17th Century it migrated to bathhouses and coffee houses and respectability. King William of Orange hired himself a private corn-cutter, and from thereon the respectability of the trade only rose. Today, most podiatrists shudder at the thought of an individual taking anything abrasive to their calluses, and recommend bringing them in for the expert care of a professional.

How to Grow Calluses When You Want Them

Calluses You Want

There is one serious reason to want calluses: to prevent pain. Many sports and exercises apply pressure to the hands and feet, while playing a string instrument hurts the fingertips. Playing a console or arcade game puts pressure on the side of the thumb, which could be alleviated by the callused condition sometimes known as 'Streetfighter thumb'. Ballet dancers need to develop heavily callused feet to dance; so ballerinas are eye-candy only from the ankles on up.

Growing Them

There are callus creams available over the counter for those who want to grow them fast. Some guitarists swab their fingertips with alcohol after play to encourage the growth of calluses. A keyring of heavy plastic with raised bumps shaped like strings allows players to keep up the pressure even when they're not playing. This encourages calluses to grow and prevents them from falling off. Others prefer to just protect the skin with fake calluses made with a bit of superglue while they wait for the real calluses to form.

How to Get Rid of Calluses When You Don't Want Them

Calluses You Don't Want

Calluses are rough and can be unpleasant, particularly if you're stroking a baby or playing barefoot footsie with someone. Additionally, they can get painful when tissue builds up from an unhealthy pressure that isn't relieved. Corns are just plain ugly, and nobody can blame you for wanting to get rid of them. If they get particularly thick, they can turn ulcerous. Diabetics grow more calluses more frequently because of poor circulation in their feet, and want to keep them down as a matter of regular practice.

If you have calluses you don't want, the first thing to do is figure out why you have them. Calluses on the feet often form because of poorly-fitting shoes or wearing sandals without socks. The best way to get rid of those is by buying shoes that fit or to wear socks. If you spend a lot of time walking, get comfortable insoles to cushion your feet, so calluses don't have to. Special insoles designed for diabetics are also available for the marching masses.

Other times, calluses on the feet are caused by fungus, in which case an anti-fungal cream is the way to go. Or, foot calluses might herald an abnormality in the foot; for example, calluses often develop behind the second or third toe when a person has bunions, because of the uneven pressure when they walk. A condition known as pes cavus, caused by neuromuscular imbalance, contorts the foot like a tripod, with all the body's weight bearing on the lateral calcaneous (outside of heel) and first and fifth metatarsal heads (either side of the ball of the foot). The result is some rather large calluses.

Some more unusual causes of calluses: calluses on the knuckles might be caused by forced vomiting and can therefore be a sign of bulimia. Arsenic can cause thickening on the palms and soles. Syphilis can also cause callus-like growth. And of course, various types of keratosis can cause calluses to grow for no particularly good reason at all.

Getting Rid of Them

Calluses and corns are dead skin, so you can trim them off without pain. Do keep things sterile if you take this path. Sandpaper or pumice can also be used to scrape them off. (If you have diabetes, don't trim on your own, because you have a higher risk of complications.) If you prefer something gentler, soak the calluses in warm water mixed with Epsom salt until the water cools, then rub the calluses with a towel. Slather on some Vaseline and cover with a cotton sock or gauze overnight. If they don't peel off the next morning, they will after a few more such treatments.

Things Called Calluses

When bones begin to heal, a spongy cartilage callus forms over the fracture, closely followed by a bony callus. Bone spurs are bony versions of corns that grow on the skeleton. Plants can also grow calluses over scrapes or cuts to their 'skin'.