Surely every runner ever has had a blister? They can range from a barely noticeable bubble to a toe that looks like an angry cherry tomato! At their worst they can make running an uncomfortable nightmare or stop you altogether. So what can you do about them?

Firstly, prevention is obviously better than cure, but that’s no help if you have one already! If you do there are a few key principles for treating them;

Let it heal Reduce the friction Use appropriate wound/ blister care Deal with the cause

Let it heal

Blisters are usually caused by excessive friction when running, your first port of call may just be a couple of days rest. Skin heals quickly so if you can re-arrange your running schedule a little, you’ll probably find it will have healed enough by the time you run again. If you need to continue running make sure you reduce friction as much as possible and dress the blister properly.

Reduce the friction

There are a few strategies for this;

Zinc Oxide tape is very useful – if the blister is still healing then place a plaster or gauze dressing over it then tape on top. If it has healed and is clean and dry you can usually tape over it. You can also tape on healthy skin to prevent blisters in vulnerable areas.

Compeed Blister Plasters are a good option – they expand in response to friction to protect the area.

Smothering the foot in Vaseline to reduce friction can also help. Cover the inside of the arch of the foot up to and including the base of the big toe. Also worth doing the tips of the toes and inbetween. Some people also put Vaseline on the outside of the sock and daub a little on the inside of the shoe where the friction is happening. Bodyglide is also a great option to use as a lubricant to reduce friction (thanks to Melissa for mentioning that in the comments section).

Select the right socks? I’ve put a question mark there because I haven’t found type of sock makes a great deal of difference to me. I’ve tried anything from £2 a pair from the bargain bin to £15 high tech ones that supposedly prevent blisters, wick sweat and occasionally complement you on your dress sense. The outcome always seems to be the same. Doubtless other runners may have socks they swear by (rather than swear at, in my case) so it’s worth shopping around and trying some out. Some favour using 2 pairs of very thin socks and this can be very effective.

Blister care

With any wound there is a risk of infection, with a blister this can delay healing, increase pain and could see you facing a couple of weeks off running. So reducing infection risk is an important part of blister care. Common sense obviously applies – keep the feet and socks clean and your nails relatively short. You may want to use an antiseptic cream such as Sudacrem/ Savlon on the blister too.

Now the big question…to pop or not to pop?

The sensible answer is usually don’t pop it – A blister is a fluid filled sack that protects raw, healing skin. It contains the nutrients the area needs to heal and forms a barrier to infection. Sticking a needle in there introduces bacteria and increases infection risk. This is also the advice of NHS choices. If you can rest from running for a few days and just let it settle this is often the most simple and safest approach. You can also use a soft dressing for comfort, even if the blister hasn’t burst.

However…this is a site for runners, when have we ever been ‘sensible’?

It may be that the blister is so large that the pressure build up is painful and you feel you really need to pop it. Or, just as likely, you need to run for an event or training and it’s too painful. This is where there is an argument for ‘popping it’. When you run it’s quite likely it will pop anyway, so it may well be safer, and less painful to do this in a controlled, relatively sterile manner at home then you can then dress it afterwards. Or, you could go to your GP or Practice Nurse for them to aspirate and dress it. Again this would be sensible and what I would recommend in an ideal world. I do however know runners, and there is little chance they’d see their GP about a blister! If you do choose to pop your blister at home then wash the foot thoroughly first and use a sterile needle.

When dressing a burst blister don’t remove the surrounding skin (this process is called de-roofing) as it protects the healing skin underneath. Allow the fluid to drain and cover with a dry, sterile dressing. NHS choices recommend hydrocolloid dressings, such as duoderm. They have more info on treating blisters and applying dressings.

Watch out for signs of infection – these include swelling, redness surrounding the blister, yellow/green discharge or puss from the wound (not to be confused with normal transparent yellowish fluid you might expect from a blister) increase in pain and excessive heat from the area.

Deal with the cause

If you simply return to running in the same shoes after a blister has formed there’s every chance it could recurr. Try to identify the cause and address it. In most cases it comes down to either your running shoes or the terrain you run on. Shoes that are too small, too big, too narrow or too wide can result in excessive friction. Also insoles or defects within the shoe can rub and cause problems. Doing lots of hill work can also cause blisters, especially on the toes as they move forward in the shoe as you run downhill.

Tips from a podiatrist

During my marathon training I saw a podiatrist who gave me a couple of tips;

Use the insole of the shoe to see how much room you have around your toes

See if you tend to ‘claw’ your toes during running. This means you tend to flex your toes into the sole of the shoe for extra stability, it causes greater pressure and friction at the end of the toes. To remedy this try and consciously relax the toes from this position, you may also need to work on your balance to improve your stability.

The knowledge of the Twittersphere has also been very helpful on the subject of blisters;

Ultra runner @runner786 aka Mark

“It’s all down to shoe choice – at least a thumbs width if not more in the end but NOT at the expense of a good fit on the heel, if you can’t get both move on.”

Ultra runner and writer for Men’s Running Magazine @jodyrunssahara

“Treat hotspots as soon as they appear. Wear the right socks. Self treat blisters. Learn from experience what works for you”

Runner and biomedical science student @tufftybluey aka Sophie

“Don’t pop them just leave them and smother them in Vaseline when running”

Runner @seesteverun

“I use 2 pairs of very thin socks, had minimal blister trouble since. On the odd occasion that I have had them, I don’t think you can beat Compeed.”

And last but certainly not least…

Experienced race doctor @isitaboutabike who has looked after runners and their feet on 100 mile ultra marathons was hugely helpful and offered lots of excellent advice,

“Prevention: shoe choice and fit, merino socks, Vaseline, don’t forget some footbeds [insoles] are better than stock, and train on race terrain – poor prep/ not testing gear in both the conditions and terrain probably main error.” “Blisters do nicely doing nothing! Doing things may help keeping going in an event or to return to training again comfortably ASAP. Once blistered my favourite is to pop/aspirate (using sterile needle and syringe) tape down with mefix* on dry clean skin, and apply Vaseline over that.”

“Compeed is very impressive if used early on dry prepped skin. Mefix on top, can last 75 miles in the wet.”

*Mefix is a self addhesive fabric tape.

Final thoughts; blisters can be a nuisance for runners. The vast majority can be dealt with successfully with a few days rests. The general rule, and safest option is not to burst a blister and to seek medical advice if a blister is very painful or shows signs of infection. You may choose to burst a blister in order to continue running, if so you do this at your own risk and you should dress the wound afterwards and keep it clean. Runners with diabetes need to be especially careful with wound care on the feet. And…as ever on RunningPhysio…if in doubt get it checked out.