To pop or not to pop is the question once a blister has formed. In the vast majority of cases it is best to leave a blister alone as it will normally heal by itself within a week or sooner. The most important thing is to cover and protect it because it is a portal of entry for infection.
“Only drain blisters if you think they’re going to pop themselves while you run,” says Pearson. “If so, be as sterile as possible and create a single needle hole at the bottom of the blister so gravity drains any re-filling fluid. Then dress and pad it.”
“Some ultra events have medical teams wielding scalpels and iodine with great enthusiasm. Treat the use of these with caution as conservative management is generally best,” he adds. “Blisters are one thing but infected blisters are a whole new world of misery and virtually guarantee the end of the race for you.”
Covering a blister with a plaster or dressing can also help to protect the skin from further damage.
“A moist hydrocolloid dressing can help to cushion the blister to reduce pain and speed up healing, and you can get specially designed blister plasters at a pharmacy,” says Gohil.
And if you are unfortunate enough to get a blood blister—a blister filled with blood rather than clear fluid, an injury common among tennis players—make sure you seek medical assistance.
“The toe is moving in the shoe and the shoe is hitting the nail multiple times which can cause a lot of shear pressure and friction,” says Owen. “If you get a blood blister under a toenail the best advice is to go and see a podiatrist, and they can drain it in a sterile environment to reduce the pressure.
“I’ve seen some issues with people who have self-treated blood blisters. You’ve got to make sure that it’s done properly so that it drains effectively. Otherwise you can end up with a recurring problem and it becomes an entry for infection.”