During my first Ironman triathlon, a well-meaning spectator decided that it was a good idea to spray the runners with his hose because it was so hot. I understand he thought he was helping because it was over 90° while we were running the marathon portion. The problem was that I developed a significant blister on my heel because of wet socks and friction in my running shoes. Honestly, that blister was more painful than any of my other aches and pains from completing an Ironman. Blisters can be nasty.
Blisters are simply caused by friction between your skin, socks, and shoes. They are significantly increased when there is moisture around. This can be from a well-meaning spectator’s hose or excessive sweating. Poorly fitting shoes or foot deformities like bunions and hammertoes can increase the incidence of blisters. Some people also have excessively hypermobile feet and their biomechanics (or the way they run) can increase the chance blisters.
Blister prevention starts and ends with properly fitting shoes, blister preventing socks, padding or friction-reducing topical Bodyglide on any deformities, orthotics to decrease motion in those with poor biomechanics and even antiperspirant for those who excessively sweat.
Properly fitting shoes means that they are wide enough and long enough to accommodate your feet. They should also be in the proper category for your foot type (neutral, stability or motion control). Shoes should be at least one-half size bigger than your street shoes, and often I recommend a full size larger due to your feet swelling while you are running.
Blister preventing socks are made out of a wicking microfiber and often have two layers so the friction occurs within the sock and not on your skin. Cotton socks are blister magnets and should be avoided.
Padding with cushioned moleskin or silicone sheeting can be helpful with bunions and hammertoes. Body glide can also be used on these high friction areas.
If you are excessively sweaty, you can either use an absorptive foot powder or even a spray antiperspirant before running to decrease the amount you sweat.
Seek the help of a podiatrist if you continue to have biomechanically induced blisters even after following these tips.
Sadly, blisters still occur even when you try to prevent them. If you do experience a blister, if it is not painful; then leave it alone. If it is under a toenail and the nail is now loose or red around it, visit your favorite podiatrist to have the toenail removed. Do not try to attempt this yourself. If you have a large blister that is extremely painful, use a sterilized needle to pop one tiny corner and remove the fluid from under the blister. Leave the overlying skin as a biological barrier and treat with either Neosporin or Betadine to decrease the chance of getting an infection. If you notice redness around the blister, drainage that is not clear or bloody looking; especially if it is looking like yellow or green pudding, seek medical attention. You probably need some antibiotics.
Blisters are nasty and can be extremely painful. Simple tips can help prevent them. Treating them immediately with sterile Instruments to prevent infection is the best way to resolve them quickly so you can get back on your run.