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Did you know that your job, your medication, or simply growing older could cause you to lose your fingerprints?
I thought (as most people do, probably) that fingerprints were forever, unless they were cut off or removed with acid, but an article in the February issue of Scientific American points out various commonplace circumstances that can alter or eradicate prints. Science writer Katherine Harmon gathered the information from experts in the field.
I am, of course, interested in this topic only as an author writing about crime. If I want to write about a character whose fingers leave no prints, how can I make it believable?
Harmon reports in her article that it’s not unusual for bricklayers to wear away their prints if they routinely handle rough materials without gloves. Handling lime can burn away prints. The most startling news is that secretaries can lose their prints by handling paper all day. This makes sense, though: paper, after all, is made from wood, and it’s not as smooth as it looks. It produces enough friction, over time, to wear down the ridges on fingertips.
If I don’t want my character to be a bricklayer or a secretary, I can give him or her a bad case of poison ivy on the hands. Rashes can remove prints – temporarily. If only the surface layer of skin is affected, it will regenerate quickly, complete with prints.
I could give my character a history of cancer treatment. Some cancer drugs can cause chemotherapy-induced acral erythema – swelling, pain and peeling of skin from the hands and the soles of the patient’s feet. Fingerprints will peel off. Annals of Oncology reported in May 2009 that a man from Singapore who had undergone chemotherapy was detained briefly on a trip to the U.S. after a routine security scan showed that he had no fingerprints.
Making the character a person of a certain age might also work. Growing old may not obliterate prints, but it can make them difficult to capture. As skin ages, the ridges on the fingertips become less prominent and the furrows become narrower, so prints will be less distinctive.
Forget about mutilation with acid or a knife – the prints might be gone, but the unique scars left behind will be every bit as incriminating.
My internet research into the possibility of changing or removing one’s fingerprints turned up a lot of sites that suggested sanding them off. But if mutilation, illness, occupation and age don’t fit the story, the simplest approach may be having the character cover his or her prints by applying a polyurethane glue such as Elmer's Ultimate. It may be uncomfortable after it dries, though, and no solvent will remove the stuff. Sooner or later it will wear off. The big advantage is that the glue is invisible and the fingers will look normal. No one will suspect a thing.
Good to know.
You can read Katherine Harmon’s article here: http://tinyurl.com/l7t6mv
