Blisters between the toes
Blisters between the toes (interdigital blisters) can be the most painful blisters of all. There are two types of blisters that could be classed as interdigital blisters:
- True interdigital blisters – blisters literally between two toes. These aren't as common as the next type - pinch blisters.
- Pinch blisters – blisters towards the bottom or end of the toe, common with adductovarus (curly) toes. The underside of the toe often takes on a triangular shape. These blisters are a result of how one toe curls under the next toe and basically gets 'trodden on' with a blister being the result.
The bony anatomy of the toes
Phalanges - toe bone anatomy
Toes are bony little things. There are 3 phalanges (toe bones) in each toe (except the big toe which has 2, like your thumb). Phalanges aren't smooth straight bones, they're pretty lumpy. Look at the x-ray of the big toe and second toe. In this image you can see the soft tissue of each toe and even the nails if you look closely. And you can see the phalanges under the skin. Notice how they are wide at the ends and skinny in the middle.
Even at the best of times, you can see how the bony prominence of one toe can press on the bony prominence of the adjacent toe. This is even more-so when a toe is bent or curly - one gets "trodden on" and pinched. And the toes don't necessarily remain still in the shoe as you walk and run. They move relative to one another.
Before we delve into ways you can prevent both types of blisters between the toes, have a look at the interdigital blister below.
How To Stop Blisters Between Toes
1. Foam or gel wedges
Foam and gel wedges keep the toes physically separated and cushion bony prominences. And the gel particularly absorbs much of the blister-causing shear via its shear modulus. Interdigital wedges are almost always comfortable because the material is soft. But they can (though not always) move around and dislodge. Apart from the toes sitting close together, there's nothing actually holding them there. In addition, in-shoe conditions (sweat/grit) cause them to degrade fairly quickly, especially with rigorous activity. These products are available at pharmacies and from some podiatrists.
2. Silicone gel toe sleeve
These are like a little sock for an individual toe and come either open or closed at one end. They offer less cushioning bulk (just because the bit between the toes is thinner) but the upside is they are more likely to stay in place because they are elasticised. They can be quite helpful for pinch blisters as the elasticity encapsulates and holds the soft tissue component of the toe together so it’s not getting "trodden on" as much with each step. But they will get sweaty and degrade over time, just like the wedges. Applying talcum powder to silicone devices after washing and drying will improve longevity.
3. Otoform K wedge
Otoform K is a moldable putty material that sets and holds its shape. Podiatrists use it frequently to achieve an even pressure along the entire interdigital space, in spite of even the most significant toe deformities. It's the best way to achieve even pressure - better than cushioning methods (above). The aim is not to straighten the toe as this would prove uncomfortable (and probably wouldn't work anyway), the aim is to avoid high focal pressure. You need to be standing while the material sets - because nonwieghtbearing toe alignment is always different to weightbearing alignment. The good thing about Otoform K is its long-lasting (months to years) and is easy to keep clean. However, they aren’t always tolerated because they can feel hard and foreign.
Tape can be used to reposition a toe, to encapsulate the soft tissue of the toe or just to protect the skin from rubbing. To reposition a toe eg: a curly toe that tucks in & under the next toe, you can tape it up & out so that it sits a bit straighter. But tape stretches and/or comes loose over time so it requires reapplication each day or sometimes several times a day depending on your activity. Because sweat is a constant threat to adhesion. For toes that suffer pinch blisters, often the fleshy underside of the toe is misshapen to the point where it can be almost triangular! Anything that can hold this soft tissue in and less triangular, means there’s less toe that the next toe can tread on – and that means less blisters. Here's a video on toe taping technique by Anna Beetham that may help.
Lubricants reduce friction. However, research shows that there is a delayed increase in friction above baseline measures So reapplication is required or not only is your blister protection gone, you're actually more likely to get blisters. And lubricants are occlusive and lock sweat within the skin and increase maceration, a common issue between the toes anyway. On the upside, if used only between the toes, at least the initial lack of traction will be a minor issue at this anatomical location. Read this article for more on how lubricants work.
Toe-socks add a little more bulk to the interdigital space so they work a bit like an interdigital wedge by cushioning. They also work like a double-sock system by forming an additional interface (sock-sock) at the interdigital space. But double-socks rely on different materials being used for friction-reducing properties and this is not the case with toesocks – it’s the same material on each side. But this small difference may be enough to stop blisters. A common brand of toe-socks is Injinji.
7. Low friction tape on toesocks
Applying an ENGO Patch to toesocks will reduce friction a lot more than the toesocks alone. You'll only need it on one interdigital surface. Remember that foot volume increases the more you are on your feet and active - so don't apply any compression around the toe! Just lay it on and press to adhere. I know of athletes that use duct tape for this application, which may suffice considering any tape will come off when you wash the sock.
Blisters between the toes can be the most painful blisters of all - and they're common. It's no wonder when you consider the anatomy and function of toes and the micro-climate of the interdigital spaces.