Blisters

A blister, also known as a bulla or phlyctena, is a sac of fluid that forms under the skin.

Causes

Friction (e.g., wearing ill-fitting shoes), burns, stings and pressure can all cause blisters.

Symptoms

• Sac filled with clear fluid or blood
• Pain

Treatment

As a general rule, you shouldn't puncture the blister; you can simply protect it with a dressing. The intact skin acts as a natural barrier against bacteria and reduces the risk of infection. The blister will resolve on its own within a few days.

Your health care professional may recommend to drain it under sterile conditions, but only if the blister is very painful, large, or at risk of bursting in situations that could lead to infection. In that case, be sure to follow the procedure described below.

• Clean your hands and the blister area with soap and water.
• Perforate the edge of the blister in several places using a needle previously sterilized with alcohol.
• Gently apply pressure on the blister with a gauze pad to drain the fluid.
• Apply a small amount of antibiotic ointment or petroleum jelly.
• Cover the empty blister with a sterile dressing. Some dressings are specially formulated for use on blisters. They absorb the fluid, promote healing and reduce pain.

Note that excess skin should not be removed as it increases the risk of infection. Simply clean the skin and cover it with a sterile dressing. Pay particular attention to signs of infection if you have diabetes or blood circulation disorder.

Prevention

To prevent blisters, simply protect any area that is prone to repeated rubbing by wearing gloves, socks, dressings or other protective devices. You can also purchase specially designed sports socks and cushioned insoles. In addition to wearing properly fitted shoes, it is important to remember that different sports activities call for specific footwear.

When should I see a health care professional?

Consult your health care provider in the following cases:

• There are signs of infection (redness, heat, swelling, pus, persistent pain and fever)
• The blisters are the result of a burn in any of the following situations:
  • Covers an extensive area
  • Is located on the face
  • Occurs in a child
  • Affects the use of the limb on which they are located