Why Do We Have Fingerprints?


A patient of mine with severe hand dermatitis has an identity problem. She applied for a job that she is well qualified to get, except she doesn’t have any fingerprints. Her job requires a security clearance, and she has to have fingerprints to verify her identity (and to verify that she isn’t wanted in Montana). But her severe hand dermatitis has left her fingertips scarred, and she is unable to give adequate fingerprints.

Why do we have fingerprints in the first place? The ridges are unique and allow you to be distinguished from billions of other people. Although wonderful for the FBI, your fingerprints were never meant to assist in identifying you.

It has been traditionally thought that the tiny ridges increase the coefficient of friction of the skin making it easier to grasp and hold things. A smooth surface makes handling delicate objects like a dime, difficult, especially if your hands are wet.

New research suggests that the grooves have another, possibly more important function: they improve your sense of touch. Fingertips are exquisitely sensitive to touch. This is partly due to a special nerve called the Pacinian corpuscle. The tips of your fingers are packed with these sensitive receptors. One sensation that they are particularly attuned to is vibration. It turns out that the ridges on your fingertips when rubbed against an object create a  fine vibration that is not noticeable to you, but is detected by your Pacinian corpuscles.

Loss of fingerprints is uncommon. It can happen from trauma, as from a burn, or from chronic skin diseases such as eczema, psoriasis, or scleroderma. There are also rare genetic conditions such as dyskeratosis congenital, an inherited condition that leads to scaly skin and increased risk of skin cancers, where patients are born without fingerprints.

Excess inflammation, as from dermatitis or psoriasis, can sometimes lead to temporary changes in the fingerprints. These changes can be resolved with topical steroids or other systemic medications to treat the underlying condition. Once the fingerprint is scarred, however, there is no way to regenerate it.

Post written by Dr. Benabio Copyright The Derm Blog 2009

Photo: D. Sharon Pruitt (flickr)

New Research Discovers Cream that Minimizes Scars

We are all scarred. Scars are a natural part of healing. They occur when there is damage to the dermis, the deeper layer of the skin. The wider and deeper the original injury, the more significant the scar will be.

Scars vary by the location of the injury and by your genetics. Some people, especially those with dark skin, are prone to develop thick, raised scars called hypertrophic scars or keloids. Keloids are more common on the upper chest, upper back, neck, and ears. Other people develop flat, white scars. In fact, even stretch marks are a type of scar.

Once a scar has developed there is little or nothing you can do to change it. Over the counter creams cannot change the appearance of a scar (no mom, not even topical vitamin E). However, your physician can sometimes surgically revise a scar or can inject it with steroid to flatten it.

A new study to be published in the Journal of Experimental Medicine has shown that the development of scars can be minimized by blocking osteopontin. Osteopontin is a protein implicated in chronic inflammatory conditions and in various types of cancer.

Research by Professor Paul Martin and colleagues at the University of Bristol shows that osteopontin (OPN) is one of the genes that triggers scarring and that applying a gel, which suppresses OPN to the wound, can accelerate healing and reduces scarring. It does this in part by increasing the regeneration of blood vessels around the wound and speeding up tissue reconstruction.

Once again, we see that chronic inflammation is the basis for disease, in this case scarring. Prescription drugs that block osteopontin are probably years away, but they might be worth the wait.

Photo of a keloid from the American Association of Family Practice Physicians. http://www.aafp.org/afp/20050801/lettersonline.html