I have often mentioned the website BlisterPrevention.com.au as a great source of information on blister care. Rebecca Rushton, manages the website and is on top of developments in the prevention and care of blisters. She’s a podiatrist in Australia – and a friend.
Through research and looking at the mechanism of how blisters form, Rebecca has changed some old theories of what causes blisters. Heat, moisture, and friction were always considered the three contributors of blisters. Further consideration has found that shear is a major factor. Shear and friction combine to cause blister formation.
I want to quote a blog post by Rebecca about Healing Foot Blisters Faster to help you understand more about friction and shear.
“You know friction is responsible for friction blisters. But I bet you think friction is rubbing. It isn’t. Friction is about grip. High friction means two surfaces grip together. Low friction means they don’t … they’re slippery.
“Here’s how friction is responsible for foot blisters … There is high friction in your shoe. There just is. This means your skin grips your sock; and your sock grips your shoe. All three surfaces grip together so your foot doesn’t slide around in your shoe.
But with every step you take, your bones are moving around under the skin. And while the skin is stuck and the bones are moving back and forth. Everything in between is pulled and stretched. This pulling and stretching is what causes blisters.
We call it shear. And it needs high friction to get anywhere near blister-causing.”
With this opening, Rebecca starts to explain the effect of shear and friction on blister formation. She talks about cutting friction levels, especially when a blister develops, and gives examples of six friction reducers. Some of these are better than others.
We have always tried to reduce friction in both preventing blisters and when treating blisters. As Rebecca says, and I support, “Otherwise all that stretching (shear) continues at the blister base while it’s trying to heal. Making it hurt more. And taking longer heal.”
So take a moment and click on the Blister Prevention link and read Rebecca’s full blog post. While you are there, I encourage you to subscribe to her email list.