An edge blister is a blister that’s kind of on the bottom of the foot, but it’s a bit on the side too. The blister is caused at an area of high pressure and friction. The tricky thing is, the blister fluid is pushed to an area that’s under less pressure, so you might concentrate your prevention strategy in the wrong place.
Edge blister case study
Debbie posted photos of her edge blisters on an episode of The Blister Hour – the photos at the top of this article.
“I think l am blaming the trainers but l have taped and creamed up. I end up like this on both feet during ultras. Any advice please?”
What would your advice be for Debbie?
This was my advice
These are all edge blisters.
It’s typical to see callous (thickened skin) where the blister originates because blisters and callouses are caused by the same factors – blisters are the acute presentation, callouses the chronic presentation. The callouses are particularly obvious below the forefoot edge blisters.
The one on the top right that looks like a classic back-of-heel blister is almost certainly at least in part an edge blister. See the lighter area on the edge of the heel – this is likely to be the point of irritation. The blister fluid has formed and been pushed up and around the heel because there is less pressure there.
Here’s a video that introduces the edge blister and shows you how to deal with friction levels.
For HEEL EDGE BLISTERS, you’ve got to look at your insole or orthotic. Look for creases in the material and make sure it’s sitting right at the back of your shoe (links below). And you have to reduce friction levels (see video above). There’s the TWO BIG THINGS that are going to make the difference.
I’ve got two important articles for you to read about how to combat these: