The Art of Lancing Blisters

Several weeks ago I was in Death Valley to help provide foot care at the Badwater Ultramarathon. Over the course of three days, I patch a lot of feet. Some on the course and some after the race was over. Yes, it was hot. Fortunately, some of the time I was in the medical room at Stovepipe Wells - out of the direct sun.

I talked to a lot of the athletes, and some of the medical staff watched to pick up pointers. As I patched feet, I tried to take time and inform the runners what I was doing and why. One thing that I have found lacking is knowing how to properly lance a blister.

Lancing a blister, or popping it, whatever term you want to use, is an important part of the patching process. Do it wrong and the blister will refill and cause pressure, pain, and may cause you to drop from the race or walk.

A pin makes a small puncture hole, which often seals back up on itself. Needles are fine, but use a large enough one to make a good hole. My suggestion if using either a pin or needle is to stretch the skin sideways to make the hole a bit larger and less likely to seal up. To start with, I use a #11 scalpel because I like the point so I can make a small nick in the blister's dead skin. A pointed scissors or nail clippers also works to make a V cut which will stay open. You want the hole to remain so fluid can drain.

On all blisters, I make cuts where 1) pressure will force fluid up, or down, and out, and 2) where gravity will continue to drain fluid. That is the most important thing to learn. Look at the photos and note the white arrows. That shows where I would make a cut.

On toes, as is shown in the first photo, make one cut at the bottom and two on top, one on each side of the nail. On heels, two cuts at the top, one on each side, and one or two on the lowest point of the bottom edge. On the ball of the foot, two nearest the toes and two near the side back towards the midfoot. Of course, the number is based on the size of the blister. Some, like the 2nd photo showing a huge blister in the arch of a foot, takes more cuts. This blister went from the base of the little toe, under callus to the arch, ands across to the other side of the midfoot.

To learn where to make the cuts, imagine the foot going through it motion. For the typical runner or walkers, the foot comes down on the heel, rolls forward to the midfoot, through to the ball of the foot, and off the toes. Not everyone is the same. Some may land on one side of the heel, roll off the side of the foot, or even land midfoot or on the toes. Walkers are more prone to ball of the foot blisters.

You want a cut or hole big enough to continue draining, but small enough so the roof of the blister, the top layer of skin, does not tear off. A cut 1/16 or 1/8 of an inch is fine. The top layer is important and provides protection to the blister. If the top layer comes off, you are putting pressure on raw skin.