What causes foot blisters?

Blisters are caused by friction from shoes or clothing which rubs repeatedly on the skin causing friction burns. As the outer layer of skin separtes from the inner layers the space between fills with lymph fluid.

They are a common problem with athletes wearing in new shoes as well as athetes or walkers who take part in exceptionally long events such as marathons or long hill walks. Blisters do not need to be a part of sporting life and can be prevented.

What can the athlete do to prevent a blister?

• Ensure that shoes fit correctly.
• Protect the potential 'hot spots' by applying a second skin and / or taping. Click here for details of how to tape the foot.
• If you wear boots such as those required for mountain walking ensure all seams are flat inside the boot. Take care of the boots, do not leave them on radiators or near heaters. This may cause the leather to shrink and seams protrude.
• Keep feet as dry as possible. Wet shoes, boots and socks will cause blisters far quicker than dry ones.
• Wherever possible change socks regularly and use foot powder to help keep them dry.

At the first sign of a blister?

• The first sign of a blister will be redness over the skin, possibly at the back of the heel, the instep or toes.
• Apply a second skin dressing and tape the effected area.
• Ensure the feet are dry and change socks (unless you are in the middle of a race).
• A highly effective but short term measure is cover the foot and effected area in petroleum jelly. This should provide instand relief from pain but as the heat from the foot melts the petrolleum jelly it will run away and be ineffective.

How can the athlete treat a blister?

• If the blister has not burst then it may be necessary to make a small hole at the edge with a steralised pin or needle, particularly if the blister is on a weight bearing surface. A pin can be sterilized by passing it through a flame.
• Do not drain a blood blister.
• Drain the fluid but leave as much of the skin as possible covering the wound. This is an important protective layer for the underlying skin and will help to prevent infection.
• Clean blisters with a steralizing wipe. Cover the blister wound with a second skin - take the time to apply it correctly.
• For additional security apply tape over top.