What are foot blisters?

James P. Ioli, DPM
Podiatric Medicine
Chances are you've suffered a blister at some point in your life, perhaps because you were trying to break in a new pair of shoes or because your feet swelled on a hot day and rubbed against your shoes. Blisters are fluid-filled sacs that develop between the top layers of skin after prolonged pressure or rubbing, which causes irritation. Blisters occur most often on the heel, the toes, or the ball of the foot. A friction blister contains clear fluid; a blood blister develops when small blood vessels are damaged and leak. A blister will hurt if you touch it, and it may break unless you take steps to bandage and protect it.

Foot blisters are unpleasant bumps that form and under the skin and are filled with water. These usually form from friction that may be caused with a new pair of shoes. At times blisters may form if you are exercising with low cut socks or not socks at all. The back of your foot near your Achilles may rub against the back of your shoe frequently to the point that a blister will form. Be sure to try and wear protective enough socks that will support your feet, allow them to breath, and hopefully prevent blisters from forming.

Foot blisters are caused by friction, the result of that friction causes a swelling of the skin that is filled with a watery fluid. The fluid builds up beneath the part of the skin being rubbed, protecting the area (like a small balloon) which causes pressure and pain.

There are a few different causes of foot blisters. Some of the most common causes being:

  •     Heat, moisture and friction.
  •     Friction caused by inappropriate shoes or socks.
  •     Fungal infections of the skin.
  •     Allergic reactions or burns.
  •     Excessive foot perspiration.

Some ways you can prevent blisters are by:

  •  Wearing shoes that fit properly.
  •  Keeping feet as dry as possible. (Wearing wet shoes, boots and socks will increase your chance of developing blisters.)
  •  Changing socks regularly.
  •  Using foot powder to help keep your feet dry.

If the blister has not "popped," leave it alone. Most of the time, the blister will reabsorb and heal on its own.


Continue Learning about Blisters

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If a foot blister develops, don't pop it. The skin provides a natural defense against infection....
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What does a foot blister look like?
Jonathan PenneyJonathan Penney
A foot blister will form as a bump. Underneath the bump will be fluid.
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What causes foot blisters?
Karen L. Gorton, PhD, MS, RNKaren L. Gorton, PhD, MS, RN
Blisters in any location are caused by increased friction between your skin and an external object. ...
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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.