[Updated] Heel edge blisters occur around the heel’s rim. They’re caused by the contour of your insole (or orthotic) heel cup.
As your blister fills with fluid, weightbearing pressure pushes the blister fluid upwards – to an area where there’s less pressure. This can trick you into thinking the blister is caused by something higher up the heel. But it’s not.
Irritation occurs at the heel rim and pressure pushes the blister fluid upwards.
Here are some more examples (apologies if you’re squeamish)! Click on an image to enlarge it.
Reduce pressure from the heel cup of your insole or orthotic
Reduce friction levels at the heel cup as it transitions into the heel counter of the shoe
Spread shear load by taping your heel
Absorb shear distortions so your skin doesn’t have to with a good cushioning material
1) Reduce Heel Cup Pressure
1a) From Your Insole
Check these things:
Your insole’s heel cup may be creased, buckled, folded, rough or protrude in some way. Replace it with a new one if you need to.
Some insoles are more contoured around the heel than others. These contours can cause edge blisters if they don’t match the contour of your heel.
Take a look at the images below. If you’re adding something on top of or below your insole, make sure it’s not creating abnormal or uneven pressure.
I’ve super-imposed a foot onto this double insert arrangement to show you why it’s problematic.
The contour of the bottom heel cushion does not match the anatomical contour of the heel because it will sit too far forward. This will create uneven pressure around the heel edge. Below are the heel edge blister that resulted within 30 miles of an event called The Wall. Ouch!
1b) From Your Orthotic
Another cause of heel edge blisters is a thick or misshapen heel cup. This will create a concentration of pressure. Your podiatrist will be able to adjust this by either heat moulding or grinding it (pictured below).
A podiatrist can grind the inside of the heel cup to make it less of an irritation; and the outside of the heel cup to make it thinner.
If your orthotic has slipped forward, you’ll be standing on the heel cup, with blisters (or at least callouses) a certainty. Apply some double sided tape under the orthotic and fix it so it’s sitting correctly at the back of your shoe. This may not work if your orthotic has made an impression into the shoe – you might not be able to fix it all the way back and make it stay there. But it’s worth a shot.
There’s a gap between the orthotic heel cup and the shoe. You’ll effectively be standing on the heel cup!
2) Make A Low-Friction Junction
With the heel cup of your insole or orthotic sorted out, if you’re still getting edge blisters, you’ll need to manage friction with ENGO Patches. This will create a low-friction junction between the shoe and the heel cup. Cover each surface with a separate oval patch using the Two Patch Technique: one patch goes on the shoe, the other on the insole or orthotic (pictured below).
Watch this video demonstration of the ENGO Two-Patch Technique for preventing heel edge blisters.
Here’s what you’ll need
You’ll need the ENGO Oval Patches from either the 4-Pack or 6-Pack. You can use the large ovals on the shoe surface, and either the large or small oval patches on your insole/orthotic.
As a last resort, in addition to the previous strategies, reduce focal shear distortions by taping your heel with a rigid sports tape. A rigid tape works better than a flexible one. I like to use Fixomull Stretch first, then the rigid tape, then another layer of Fixomull. Watch the video for a demo.
If you need even more protection, after you’ve taped your heel, tape a thin cushioned material over your blister-prone heel edge. Something like poron (PPT) 3mm maximum. This is going to take some experimentation to make sure it’s comfortable. If an edge of your pad is under your heel, this edge may become uncomfortable. Bevel the edges to minimise discomfort.
Heel edge blisters absolutely require that you reduce any undue pressure from your insole or orthotic heel cup, if it exists. If that’s insufficient, reduce friction levels with the ENGO Two-Patch technique. And if you’re especially unlucky and you need even more protection than that, add taping and cushioning.
Get Started With ENGO Patches
ENGO Blister Patches 6-Pack
ENGO Blister Patches 6-Pack contains 4 large and 2 small oval patches. It's a versatile blister pack for most blister situations, including toe blisters.