Somewhat morbid question: could one create a "human callus"?

Factual Questions
1

So I have this callus on my right big toe that I never felt or noticed until relatively recently. That put in mind calluses that were on my thumb and ring finger from high school, when I used a pencil for hours a day; both are since healed in these days of keyboards.

It did make me wonder, though (and make any assumptions you want about my imagination from this; it’ll probably be at least 25% true): suppose a sadistic mad scientist invents a device that, when a person is inserted into it, rubs that person’s skin constantly, all over their body, in a way that, on a single part, would eventually create a callus. Would such a theoretical unfortunate’s entire body be callused?

2

I don’t think so - I think at least some of the more delicate skin areas would form sores, which, if they healed, would turn into scar tissue.

3

I’d say, if done right, yes. But some areas would be more…challenging…than others…

4

At least one part of my body didn’t develop calluses in my teenage years, in spite of very frequent rubbing… :smiley:

5

Some years ago I saw a documentary about a primitive tribe somewhere (can’t remember where) in which each man carried his canoe the same way, with a crossbar across the back of his neck. Over time a massive callus developed on this area; the men all looked like hunchbacks.

Wikipedia suggests that calluses can occur anywhere, and that the key is a particular degree of friction/frequency of the rubbing: too much, and you end up with blisters, but just enough, you end up with calluses.

6

It would take a callous individual to do that, though.

7

Swear to god, my hands don’t form calluses. They just peel instead, to reveal a fresh patch of baby soft skin.

Being a guy, I’m not too fond of this.

8

Sounds like you’re trying to induce all-over hyperkeratosis.

The existing family of all-over hyperkeratoses is ichthyosis. The worst example of this is Harlequin-type, a congenital (genetic) condition where a baby is born with all-over thick callus-like skin. Which is a problem: calluses aren’t flexible, so the skin cracks deeply everywhere the body flexes, and the thickness and growth makes the skin break apart into thick plates separated by deep moist fissures of exposed dermis. Unless heroically and continuously treated, it has usually lead to death by massive infection, dehydration, or thermal disorders.

So an all-over callus would be like Harlequin ichthyosis, which is a chronic life-threatening condition. Doesn’t sound like fun to me.

Of course, not all calluses are deep, so if you restrict yourself to a lesser-degree ichthyosis, your victim is probably stuck needing a lifetime of using moisturizers and exfoliation to keep the thickened skin supple enough to not crack and itch. Still not fun.