Blisters: Learn to prevent and treat these painful adventure-killers

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Blisters can ruin any adventure faster than just about anything else. If you’ve ever experienced that sharp sting on your heel as you take each painful step after the other, you’ll appreciate this article.

So what exactly causes blisters and how can you prevent them from happening?

What causes blisters?

In scientific terms, blisters occur when friction and shear stress on the epithelium result in delamination of the stratum granulosum and spinosum and a cleft forms that then fills with fluid. The cleft retains a protective roof composed of the stratum corneum and granulosum.

In more common terms, a blister happens when your skin stretches, is damaged, and the inner and outer layers peel apart and a fluid-filled sack forms between the layers.

Friction is the primary force causing your skin to stretch enough to separate the two layers to form blisters, but other variables make it easier for blisters to form. We’ll discuss several of these factors in our efforts to prevent blisters.

Heat

Many blister articles you’ll read will cite heat as a primary factor. Heat can certainly cause blisters as anyone who’s ever had a severe sunburn will attest. However, heat actually doesn’t directly contribute to friction blisters. Heat makes your feet swell and change shape which can increase rubbing. Hot skin becomes more pliable and more prone to damage from friction. Heat also increases sweating, which leads to moist feet. Heat itself does not cause or directly contribute to friction blisters.

Moisture

So since I’ve burst your bubble on the heat factor, what about moisture? Wet skin is definitely different than heat, but it also does not directly cause friction blisters. What moisture does do is increase friction between whatever surfaces are already rubbing as well as softening and weakening the skin.

Due to these factors, moisture reduction definitely plays a key role in blister prevention.

Pressure

Whether due to added weight on your feet from a heavy pack or from shoes that are too tight, pressure on your feet adds to blister formation. Pressure leads to additional friction and also increases the shearing forces that damage your skin.

Friction

So again, friction itself isn’t what causes blisters. Blisters happen when the inner and outer layers of your skin stretch and separate. However, friction on your skin will lead to separation of the layers. Friction happens when your foot doesn’t fit snugly into your shoe and there’s space for it to move around. If you’ve got any extra space in your shoe, your foot will slip and slide causing your foot to rub on your sock and your sock to rub on your shoe.

The friction from this rubbing will lead to blisters so how do we prevent it? It’s nearly impossible to get a perfectly snug and vacuum molded shoe for all activities, and even if you could, your foot shape and size changes, so you’ll never eliminate friction. Since friction is here to stay, let’s discuss ways to prevent blisters in spite of the shearing and rubbing forces we put on our feet as we adventure.

How to prevent blisters?

I know you probably don’t care so much about how blisters are formed, you just want to prevent them from forming. Let’s get to it!

Before your adventure

Blister prevention starts long before you start your adventures. It takes having the right gear, prepping your body, and preparing yourself for whatever situations you may run into while out having fun.

Choose the right shoes

Size

Let’s start with your shoes. Choosing the right shoes is paramount to preventing blisters. The most important aspect of your footwear is that it fits properly. Too tight, and you’ll add significant pressure to your heel, toes, or other parts of your feet. Too loose and your foot will slide around and you’ll be sure to have blisters. Getting the right fit is harder than just picking the right shoe size.

It starts with picking the right shoe size, but even if you get the right size, the fit has to be just right. Too much space in the toe box and your feet will slide side to side. Too little space and your toes will squish together and rub. The heel cup also has to be the right fit for your heel or you’ll end up rubbing right into a heel blister. Try switching models or brands until you find a shoe that fits like Cinderella’s glass slipper.

Fit

Some tips to finding the right shoe is to wear the same socks you plan to take on your adventures and test out the shoe on an inclined slope both up and down. Most good shoe fitting stores have a ramp to test this out on. If you plan to run at all in your shoes, test out a quick run around the store before you buy to ensure the running motion doesn’t cause rubbing.

If you find one that’s good enough, go for it. You’ll break in the shoe before you hit the trail so any small inconsistencies can be worked out.

One additional tip if you find a shoe that fits well, but isn’t perfectly snug is to test different lacing configurations.

Here’s a quick download of the different lacing configurations I use for different types of shoe fit problems.

Use

Not only do you have to get the size and fit right, but you also need to consider what you’ll be using the shoe for. Will you be hiking in hot, dry weather? Wet and cold? Hot and wet? My general rule is that if a shoe will be used anywhere hot, whether in dry or wet conditions, I opt for light or midweight trail running shoes with good ventilation or other sport-specific shoes.

For wet activities like canyoneering, river rafting or hikes with multiple water crossings, I choose shoes that will drain and dry quickly and adequately protect my feet. I love my Chacos for kayaking and rafting, but like to use lightweight trail running shoes with good grip for canyoneering or other water walking adventures.

If I’ll be using the shoes for cold activities, I prefer a heavier shoe and usually get one with Goretex or other waterproofing. The risk here is that waterproofing reduces breathability and therefore increases the chance your foot will get wet from sweat. Take this into consideration along with the range of socks you can use with the shoes to moderate for temperature. I wear the Montrail Masochist for most of my trail running since I often run on cold or wet trails.

Read here to learn about winter trail running

If you know it will be cold, but not wet, get a nice warm hiking shoe.

So now you’re probably saying, “I want a shoe that will work in all these scenarios.” If you’re like me, I avoid buying tons of gear and stay minimal so buying a shoe for every weather scenario doesn’t make sense. For most all my adventures I make do with just a few pairs of shoes. I have a lightweight trail runner, a heavier waterproof trail runner, a pair of alpine touring ski boots, and then my Chaco sandals. This mix keeps me going in all kinds of terrain.

Choose the right socks

Shoes are only half of the equation for purchasing the right gear for blister prevention. Socks go directly on your feet so play a critical role in blister prevention. The most important consideration is to avoid cotton socks. They absorb moisture and will keep your feet sweaty and wet.

Get either wool, synthetic, or a synthetic-wool blend. I personally prefer merino wool or merino wool blends for all my socks. I have three thicknesses and just pick one based on the expected weather.

Some people get fancy and layer their socks with a liner and an outer layer. You can try this if you want, but I find that properly fitting shoes along with a good soft merino wool sock is all I need.

I use a lightweight sock for hot weather, a midweight for mixed weather, and a heavy sock for cold weather. That keeps it simple and makes it easy to figure out what my sock-shoe plan will be for any adventure.

Here are the socks I like to use for various conditions.

Toughen up your feet

Another way you can prepare for blisters before your adventure is to toughen up your feet and break in your gear. Once you’ve selected the right socks and shoes for your trips, put them on and walk around in them. You can take them on short hikes or just wear them around town. The important thing is that you put in some time getting your feet used to wearing this gear.

I purchased a pair of trail runners a while back and my first run I got a heel blister on each heel. I didn’t go on a long run though, so it was no big deal. The next time I went out, I had no issues and I’ve never had an issue since. It would have sucked to get those heel blisters in the first few miles of a long trip!

Pay attention to any hotspots or pressure points as you walk around, both uphill and downhill. Are your feet or heel slipping around? If so, adjust the lacing pattern to lock in your heel or toes, get an insole, wear thicker socks, or find a better-fitting shoe. Are there pressure points? You can sometimes work out a pressure point by working the shoe material with a blunt object like the dull end of a screwdriver. A bit of massaging can remove bumps or seams that rub on your feet.

Prepare for the worst

When it’s time to pack for your adventure, prepare for the worst but expect the best.

A bit of preparation beforehand can make all the difference.

When I was 14 I went on my first 50-mile backpacking trip. Leading up to the trip I found that I had a terrible ingrown toenail on my big toe. I tried to clean it out on my own for a week or so, but it only got infected. It was pretty ugly the weekend before my hike and hurt to walk on. There was no way I was going to do 50 miles on that thing so I popped some Tylenol, soaked my foot in hot water, doused it in rubbing alcohol, and proceeded to rip my entire toenail off with a pair of pliers. It wasn’t pretty but it sure did make my toe feel better after a day or so!

Read about another backpacking adventure from my youth here.

I was able to complete the hike without any foot issues or blisters but had I not ripped off my toenail, I’m sure it would have been a painful bloody mess.

Prevention

Packing for blister prevention isn’t hard but makes a big difference when it counts. Since moisture is a key factor in blister development, keeping our feet dry will go a long way to avoid blisters. If you pack so you have two pairs of socks on hand while you’re hiking – one on your feet and a spare at the ready – you can swap them out each time you stop or your feet get wet. The spare pair can dry out while you hike. With wool or synthetic socks, hanging them on the side of your pack for a bit will dry them out quickly so long as it’s not raining.

The extra prep of having spare socks is an easy way to keep blisters at bay all day.

Protection

In addition to the right gear, there are blister prevention products you can use to reduce friction before hotspots even start. The ENGO blister patches are one promising solution.

I’ve never used this product, but in my research, it stood out far above the rest as a preventative measure for blisters. They’re basically Teflon-coated patches that you stick to the inside of your shoe. The Teflon layer significantly reduces friction where any trouble spots may form.

Again, I’ve never tried them, but they look promising if you know you’re a blister former. The only limitation I saw was that they don’t stick well if they start to get too wet so don’t plan on using them if you’ve got river crossings planned.

Another preventative product you can be ready with is tape. Putting tape on any blister-prone spots on your feet before you even start can go a long way to staving off hotspots and blisters. My favorite tape is Fixomull Stretch tape. It’s totally waterproof and stretches well so it’s durable enough for tough, wet activities like canyoneering. Put some on before a hike starts or put it on when you start to feel a hotspot.

Preparation

A common spot to get blisters is around your toes and one of the reasons for this is your toenails. If you clip your toenails really well and file them down before your adventures, you can reduce the occurrence of toe blisters.

After doing all you can ahead of time to prevent blisters, you may still end up getting some. In this case, it pays to be ready to treat them well. Always go prepared with a first aid kit that contains blister treatment items. Below is a list of what should be in your blister treatment kit.

Items to put in your blister treatment kit

• Fixomull Stretch tape – Waterproof, flexible, adhesive to cover trouble spots and hold other dressings in place
• Gel toe sleeves – Toe protectors that help separate toes from each other
• Moleskin – Padded adhesive that can be easily cut and shaped
• Scalpel blades – Used to lance blisters and cut dressing material
• ENGO patches – Anti-friction patches for your shoes
• Iodine swabs – Antibacterial swabs for dressing blisters that rupture
• Nitrile gloves – Keep things clean
• Compeed dressings – Dressings that absorb moisture, protect injured skin, and speed healing
• Island bandages – Absorbent bandages with adhesive on all four sides of the pad. Use these over bandaids to keep the wound clean
• Skin Prep swabs – Adhesive prep to help any dressing applied stick better

You can buy all these individually or you can buy a premade blister kit with all the best supplies here:

During your adventure

Now that you’ve done all the prep work, it’s time to relax and get out there adventuring. With the right shoes, socks, and a prevention plan in place blisters shouldn’t bother you.

As you hike, pay attention to your feet. if they start to get hot and sweaty, you’re playing a risky game. It may be wise to stop and dry them off. Dipping your feet in a cool stream feels great on hot feet. It’s also important to keep your feet clean. If you feel you’re getting dirt, sand, or other debris in your shoes, it’s important to stop and clean off your feet. Again, a stream is great for this.

Just be sure to thoroughly dry them off when you’re done. Stopping is also a great time to swap out your socks for the fresh pair you have handy in your pack.

But what if you start to get a blister anyway?

Treat hotspots quickly

If you start to feel a hotspot, it’s basically a pre-blister. It’s a red flag that if you don’t take action, you’ll have a blister soon. So what should you do? STOP! Stop and take care of it now. Don’t tough through it, don’t be worried your partners will be annoyed. They’ll be much more annoyed if you can’t walk. Just call it out that you need to stop to fix a hotspot.

Sit down and check out what’s going on. Is your sock bunched up? Is your foot wet? Do you have sand in your shoe? See if you can find the cause of the issue so you can properly resolve it before it becomes worse. Depending on the problem, put some tape on it, swap out for a fresh pair of socks, adjust your shoe lacing, and then keep going.

When you get a blister

So what happens if you stop again and find that your hotspot is now a full-on blister? Good thing you’ve got your blister kit handy because you’ve got options to treat that sucker so your trip won’t be ruined.

To pop or not to pop

One of the first questions you should ask is if you should pop and drain the blister or not. General wisdom says to not pop a blister because you expose yourself to bacteria and infection, but it’s almost always better to pop a friction blister on your feet in a controlled manner while on the trail. It’s much better to control the process than to have the blister rupture on its own and get filled with dirt and debris – especially if you’re slogging through nasty, swampy, canyon water. The only time I don’t pop blisters is if I don’t notice them until I’m already done with my trekking.

How do you properly pop a blister?

So you’ve decided it’s best to pop this thing. How should you do it? The main goals are to prevent infection and reduce pain.

Prevent infection

To prevent infection, you first want to clean off the area from sand, dirt, mud, or other large debris. I like to start by using my sock to wipe the area clean. Merino wool socks work great for this. Then you’ll want to sterilize the area using your betadine antibacterial wipes. Wipe it clean including the general area around the blister. Let it dry and then using your scalpel or a sterilized tip of a knife or needle poke a small hole on the side of the blister least likely to get ripped open by your rubbing sock.

Once you’ve got a large enough incision that the fluid starts to drain out, gently roll your fingers from the opposite side to drain the fluid out. The damaged skin will continue to produce fluid as part of the healing process so if you don’t make a large enough hole, it will fill up again causing more pain.

The next step is to protect the damaged skin. Do this by putting a bandage over the area. Many people will advise taping with duct tape. I don’t recommend taping directly to the skin because it’s really hard to get the tape off the blister without further damaging the skin or entirely ripping the roof of the blister off. Don’t rip or cut off the roof of the blister! It’s naturally protective. Use an island dressing or an adhesive bandage and then apply tape over the top of that if you feel it will help. I don’t like to use normal Bandaids because they leave room for sand, dirt, and grit to get into the wound. An island dressing will seal it on all sides. You can also use Skin Tac or benzoin ointment to help the bandages stick better. Benzoin ointment is also naturally anti-bactericidal.

Reduce pain

To reduce pain and keep your adventures going, you can prevent more rubbing by applying an ENGO patch to your shoe where the blister formed as well as taping a piece of orthopedic felt pad to your foot.

Continue to be vigilant watching for additional hotspots as you tend to change your step pattern and gait when you’re in pain and any change in how you walk can put pressure and friction on new spots on your feet.

Once you get to camp or back to the car, you can remove your shoes and socks and elevate your foot to help reduce any swelling. If the blister is still intact, don’t pop it, just let it heal with the roof on. If you’ve popped it and dressed it, you can change the dressing and reclean the wound if it’s in bad shape. If it popped on its own, be sure to clean and disinfect it well and then dress it with an adhesive bandage or gauze and Fixomull Stretch tape.

After your adventure

Once you get home, you’ll need to continue to care for your blister to ensure it heals quickly and take precautions to ensure you don’t repeat the same blister next time. Allow it to heal fully before your next adventure if you can.

Take photos and notes

I like to take photos of any blisters and write notes about what shoes and socks I was wearing and what conditions led to the blister. This will give you tools to help prevent the same blister next time. If you got a heel blister, next time you can pretape your heel in the same spot and perhaps apply an ENGO pad before you head out. Having the knowledge of where you got blisters previously helps keep them away better than just about anything else besides having a properly fitting pair of shoes.

Treat the blister

Continue to care for the wounded skin by regularly changing the dressings and cleaning the wound as you would for any other cut. If the blister doesn’t isn’t already popped, it will usually heal well on its own. A callous will form offering you additional protection for next time.

Prep for the next adventure

Once your blister is fully healed, you’re ready to head out on your next adventure. Restock your blister kit, prep your footwear, and head out there safely and confidently knowing you’ve done all you can to prevent blisters.

If you have additional experiences or wisdom in preventing or treating blisters, share them below for others to learn from.