What are Blisters?

Previously we all thought blisters were caused by rubbing, heat and moisture, however more recently the research has suggested that blisters are caused by skin stretching, which is called shearing forces.

Shear might seem like rubbing but it’s not. Shear happens internally, whereas rubbing happens to the surface of the skin. The layers of the skin slide across each other and with rubbing this occurs to the surface of the skin. When skin shear is excessive and repetitive, blisters form.


We need to prevent the shearing forces and this can be done a number of ways.

  • Shoe fitting and laces
  • Socks: getting socks that wick the moisture away from the skin
  • Orthotics: changes the foot position to prevent shearing forces.
  • Taping, plasters, dressings: Act as a barrier and prevent abrasions
  • Skin Adaptation
  • Lubricants: Initially reduce forces and friction
  • Running technique: can help if technique is the problem.


Ideally you do not pop the blister, allow the fluid to be reabsorbed and to heal on its own. However if the blister is in an irritated place i.e. like your arch or the back of your heel, then using a sterile needle to release the fluid can help.

Do not remove the overlying tissue though, this is to protect the tissues underneath and help prevent infection. Once this has been done cover the blister with a sterile fabric band aid.