What is a Blood Blister – The bubble appears when there is friction between feet, socks, sneakers and the ground. It is most common in regions where the bone is protruding, such as on the heels and the little finger. It forms when a layer of skin takes off (because of friction) and fills with liquid, usually colorless. If a blood vessel ruptures in the detachment of the skin, the bubble fills with blood.
What to do?
Dermatologists recommend that the blister is blown only if it causes pain. The ideal is to take a disposable syringe needle, make a small hole in the base of the bubble and drain the liquid.
It is important not to remove the ceiling (the skin) since it serves as a biological dressing and protects against infections. In the case of the blood bubble, if it is painful it should be pierced within the first few hours after the formation. “Otherwise the blood coagulates and only goes out if the ceiling of the blister is removed,” explains Patricia Chinelli, a dermatologist at the USP’s Hospital das Clínicas.
The athlete can use a healing antibiotic, which fights bacteria and heals the wound faster. All you need to do is look for a doctor when there is a sign of infection, that is when the blister area is hot, very red or with yellow discharge (pus).
Bubbles and sport?
“Ideally, as long as you have blisters, the person is resting, as in any case of injury,” says dermatologist Ediléia Bagatin, from the Department of Dermatology at the Federal University of São Paulo (UNIFESP).
Dr. Milton Mizumoto, an orthopedist specialized in sports medicine and medical director of Corporate (Corredores Paulistas Reunidos), recommends placing a band-aid on the blister, passing vaseline over the band-aid, bandaging the region with a layer of micropore-type plaster, the plaster and use a liner under the main sock, which should be very soft. “Since doing that, I’ve never had a problem running,” says the doctor, who has done 26 marathons and five ultramarathons.
If the bubble is between the toes, there are also special finger protectors, made of silicone and foam, available for sale in podiatry stores. Carlos Eduardo Lefèvre, Cadu, who specializes in sports psychology, has been running long-term events in situations of extreme discomforts, such as the Desert Cup (220km in the desert sand of Jordan). When it has blisters, it passes an imported product called second skin, which causes a hardening effect of the skin similar to that of the super bonder glue.
How to prevent?
Although very common, it is possible to avoid them. “Knowing how to choose sneakers and socks, the athlete reduces the chance of having blisters,” said Cláudio Castilho, president of the Association of Racing Coaches of São Paulo (ATC).
Cadu never wears a pair of new sneakers on the races. “I used a lot of shoes before, so he could get my foot shape,” he says. He says he did not have a bubble in the Desert Cup. “The most important thing was that I used a liner under my sock,” he says.
The liner is a specific stocking to be used below the main sock and has the characteristic of absorbing most of the friction that would occur between the sock and the skin, which occurred between the two socks, so the foot was preserved.