So, you got a paper cut, huh? Not quite sure how a piece of paper can cause so much pain in your life? Or why it hurts so darn much? Or what the best way to deal with it?
Don't worry, we've got all the answers.
How It Happens
No, paper edges aren't made of teeny tiny knives. A loose piece of paper in itself is way too soft to actually do major damage. The problem arises when there's enough pressure on the paper to cut the skin. Most commonly, paper cuts are caused by sheets of paper that are bundled together with one sheet being dislodged from the rest. The other sheets hold the loose one in position, causing it to act like a razor blade and slice your skin. Ouch.
Of course, thicker paper like cardstock and even cardboard can also cause paper cuts because of the structure of the material. The stiff, abrasive nature of the paper gives it the necessary pressure to cut your skin.
Our skin is able to withstand basic pinpoint forces due to the way our collagen fibers are laid out. However, it can't withstand the motion of sawing or shearing.
So Why Does It Hurt So Much?
You probably think paper cuts hurt so much because it's an open wound, just like a scraped knee. But the reality is the pain you experience from a paper cut is far different than a regular scratch.
Paper cuts can stimulate a large number of pain receptors on your skin. The cuts are rarely that deep, so they don't bleed excessively. The lack of blood means your pain receptors (which are nerves) are left directly exposed to the air for a prolonged period of time. This over-stimulation from the air is what causes your paper cuts to hurt so badly.
Now, I know what you're thinking. "I've gotten deep paper cuts before and they still hurt even though they're bleeding!" Yes, this can happen. Because the wound is deeper, you're exposed to the chemicals on the paper fibers, such as bleach. Imagine pouring bleach into an open wound? No thanks.
In general, your fingers have a greater concentration of sensory receptors than the rest of your body, which is why the pain feels more intense from a small cut.