Blisters : Causes And Management
Most hillwalkers and climbers will have suffered from blisters on
their feet at some time. Their effects range from mildly irritating
to debilitating depending on their severity, or how far from being
able to get your boots off you are! If ignored or inappropriately
treated they can become infected and pose a serious health problem.
Although in size blisters appear insignificant, when burst and
causing pain they can severely restrict mobility, affecting the
walkers concentration and judgement.
What are blisters and how are they formed ?
Blisters are wounds caused by a combination of pressure and friction
which when applied to the skin of the foot can lead to a gap forming
between the layers of the skin. Into the gap that is created flows
lymph fluid, as the layers of the skin remain intact at the edges of
the blister the lymph cannot escape and so the detached layer of skin
is raised up. After the layers of skin have become separated in can
take up to two hours before the blister is filled. Once a blister has
filled it is only a matter of time before it bursts if no action is
taken to reduce the pressure and friction forces it is subjected to.
Pressure Friction and Moisture.
Large amounts of pressure and friction are required to develop a
blister. Where small amounts of these factors are applied to the
skin, it tends to respond by the formation of calluses. These
calluses can be seen on the soles of the feet and on the hands. In
situations where there is an increase in the normal amounts of
pressure and friction, blisters can form in a very short time. Where
footwear is to tight restrictive pressure can be applied to the
prominent areas of the foot particularly the heel and the ball of the
foot. Where socks have been allowed to loosen and form wrinkles
pressure can build up as the sock occupies the small space between
the foot and boot.
Friction describes the rubbing motion caused by each step. As the
ball of the foot strikes the ground pressure is maximised upon the
heel area and the heel striking the ground causes a small amount of
movement between the foot, sock and boot. Vulnerable areas of the
foot are subjected to a heavy rubbing motion. As a walk progresses so
the forces are repeated and the skin becomes hot and the damage begins.
Damage caused by pressure and friction is exacerbated when the skin
surface is moist, usually sweat or water leaking into the boot.
Moisture softens the skin making it more susceptible to damage from
pressure and friction.
Early warning signs of blister formation
- Redness of the skin
- Heat on the surface of the skin
- Pain or discomfort on a prominent part of the foot
- Care should be taken to break in new boots around the house or on low
level short walks before venturing further afield. After wearing the
boots for a number of hours in the house a visual inspection should
be undertaken of the feet. It should be remembered that any small
slightly painful areas experienced while ascending the stairs of your
house could become painful debilitating blisters after 10 miles on
tougher terrain. Where the boots are giving problems due to hard
edges etc they should be returned to the shop for advice or visit the
local shoe maker for softening.
- The choice of socks is vital as they can both reduce the pressure and
friction applied to the skin while also reducing the amount of
moisture on the skin surface. Thick socks that provide padding for
the heel and sole of the foot will help reduce the chance of
blistering. Socks made of an absorbent material such as wool will
absorb some of the moisture on the skin, thus reducing the chance of
softening the skin.
- Skin Care
- If you have suffered for blisters in the past it is very important to
recognise that the tissue will be more susceptible to damage again.
Vigilance will be required and it may be prudent to change in to
fresh socks on hot days when extra moisture will be present on the
skin surface. Some people advocate the use of Vaseline on the skin to
reduce friction, while this idea could be useful on a long walk
frequent stops would be required to re apply the gel. Keeping the
skin dry is important and to this end talc may be useful.
What if your best laid plans fail and you develop a blister. Many
different treatments /tortures have been used in the past, the
author has focused on the more rational options! There are two
distinct schools of thought regarding the treatment of an intact
blister, with little research to support one over the other. Both
are discussed below, each to their own.
Treatment of an intact blister
- Option one
- It is suggested that where a blister is intact treatment should focus
on preserving the status quo and if left alone the blister will heal
on its own without infection. This is done by reducing the pressure
on the blistered area by the use of for example a corn plaster placed around the damaged tissue. Theoretically this should
prevent the application of pressure or friction to the affected area.
This can be covered over with a large fabric plaster or sports tape.
Care should be taken to ensure that the adhesive of the tape does not
come into contact with the damaged skin as this might lead to
bursting when removed. This method can take some time to master but
the author has had some success particularly with small blisters.
- Option two
- Others believe that as the blister was formed as a result of pressure
and friction, once back in the boot the foot will be subjected to the
same forces as caused the injury. Therefore it will be very difficult
to prevent the blister bursting of its own volition. Where a blister
has been found intact it should be swabbed with an antiseptic,
drained using a sterile needle and the liquid gently squeezed out.
Any loose skin should be removed from over the wound, careful hygiene
should be observed to reduce the chance of infection. A dressing
designed to provide a moist healing environment and able to
withstand the pressure and friction placed upon on the wound while walking.
Treatment of a burst blister
In the event of a blister bursting the loose skin should be removed.
Where possible the foot should be washed in water and cleaned with an
antiseptic swab. Since the 1960s it has been recognised that wounds
heal faster if they are occluded and kept in a moist environment,
this also reduces the chance of infection. Traditional plasters
should not be used as they fail to occlude the wound nor do they
provide a moist healing environment. Instead a modern wound
management product should be chosen. Most of the treatments available
in pharmacies are Hydrocolloids, adhesive dressings with a film
backing. Hydrocolloids are interactive dressings with a brown base
which becomes a yellow gel after contact with wound exudate. The gel
provides a moist environment thus promoting wound healing. While
allowing gas to escape from the wound the dressing does not allow
contamination from the environment in to the wound, reducing the
risk of wound infection. Any product chosen should adhere to the
- Sufficiently adhesive to withstand the rigours of walking etc.
- Promote moist wound healing
- Is an occlusive dressing that allows gas to escape while acting as
a barrier against in coming infection.
Foot blisters have afflicted hillwalkers and climbers for generations
but they are for the most part preventable. Where they have occurred
their management should not pose any major problems to the prepared
walker. When left to their own devices they will detract from the day
or could lead to infection. Large blisters could slow the pace of a
walker which in difficult conditions could have serious consequences.
The Department of Tissue Viability is currently conducting research
into blisters experienced by hillwalkers. Clinics are held (in Aberdeen) on Mondays
2pm-8pm to arrange an appointment contact 01224 552328.
David Gray, October 2000
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