Blisters

What are blisters?

Blisters are a fluid filled lump under your skin, that can be filled with clear fluid, blood or pus.

Who gets blisters?

Blisters are the most common running injury with 39% of runners experiencing blisters. 40% of soldiers and 50% of hikers experience blisters also. (Ritchie 2010)

How do we get blisters?

1. Blisters are a tear under the skin surface caused by the skin and bone moving out of sync. *
2. As the bones move within the foot with each step, the skin does not immediately follow. And so the soft tissues in between are made to stretch and distort. This is called shear distortion. *
3. If there is too much shear, a tear develops under the skin surface which later fills with fluid to become a blister. *

* Quotes from Rebecca Rushton. For fantastic advice and guidance please check out the Blister Prevention website from Podiatrist Rebecca Rushton who is a specialist in blister management.

Blister Myth

It’s all about rubbing (friction) from heat and moisture. Oh no its not! Check out the video by Rebecca Rushton or listen to the her on the The Shoephoria Podcast.

Friction is both rubbing and resistance. Low friction reduces resistance to movement meaning it is easier for movement by slip/slide/rub at each step. Rubbing does not cause blisters. High friction is where things stick together for longer, increasing resistance to movement.

Where does the blister tear?

The tear occurs in the top three layers if the epidermis: stratum corneum, stratum lucidum and stratum granulosum and the underlying stratum spinosum.

How to prevent blisters?

1. To reduce shear we can reduce friction to low friction levels at interfaces.
   • Skin to sock with lubricants and powders
   • Sock to shoes with engo patches (Blister Prevention)
   • Sock to sock with Arma skin socks (Arma Skin)
2. Reduce mechanical movement
   • Gel sleeves and toe caps
   • Toe props
   • Improve muscle strength/stretch 
   • Improve shoe fit with different lacing techniques

How to treat blisters?

In order to treat the blister correctly you must select the appropriate treatment for the stage your blister is:

1. Roof intact. The aim is to protect the blister roof by using an island dressing. This should keep the roof intact, the skin is keeping the blister fluid in AND keeping infection out. An island dressing will not stick to the blister and should not pull the skin off.
2. Torn Roof. The aim is to prevent infection. We will do the same as above, with the addition of   an antiseptic dressing. Leave the torn skin attached if possible.
3. Deroofed. The aim is to get good skin healing as quickly as possible, as this blister will be more  painful, open to infection and take longer to heal. You should use a hydrocolloid blister plaster such as compeed. 

It’s only a blister, what’s the worst that can happen?

Blisters can become deroofed and can lead onto complications such as infection, cellulitis, sepsis and in severe circumstances toxic shock syndrome. Treat them in the early stage.

Useful websites

• Doug Richie 2010
• Blister Prevention
• The Shoephoria Podcast