Increased skin hydration, as in sweating during exercise, reduces the ability of the outer layer of epithelial skin to cope with dynamic friction. Unable to act as a sheer protector when local temperatures increase, pooling of fluid results and when a cavity forms within a split in the stratum spinosum. The simple blister contains clear transudate and provided the blister site has no secondarily infection significant inflammatory infiltrate is not always observed. The most vulnerable parts of the foot are the back and bottom of the heel although the toes can also be effected.
Simple epidermal blisters do not pose serious health risks although they are irritating and guaranteed to ruin a good workout or a long walk. Blood blister arise when dynamic friction causes the skin to bleed into the blister. This is often accompanied with burning pains.
Simple blisters are best left alone because careless treatment can manifest into more serious infections. Tempting as it may be, "popping" a blister by pricking it with an unsterilized needle is not recommend and tearing off the top skin is definitely not the way to go. In most cases small, unbroken blisters should be strapped tightly with an adhesive bandage to give a sturdy ‘second skin’ and reduce the effect of sheer whilst encouraging fluid reabsorption.
In the case of painful unbroken blisters, home treatment may involve disinfecting a dressing pin by either boiling it or cleaning it with an alcohol wipe before puncturing the blister in two separate places to encourage draining. This takes the pain away and should be followed by an antiseptic footbath such tablespoon of common salt dissolved in warm hand-hot water (46 0C) for 10 minutes.
Simple ways to prevent blisters is to maintain good foot hygiene at all times. Wear comfortable sports shoes appropriate to activity and regularly inspect and replace them when excess wear is apparent. Socks should be acrylic/cotton mix as these retain less moisture and dry quickly. Socks with low friction against the foot helps reduce plantar shear and many athletes wear their socks inside out to prevent seams rubbing on the toes. Some people wear two pairs of socks (one thick, one thin). This allows the sheer to occur between the layers of socks rather than between the shoe and the skin. Socks with reinforced heels and toes (double knit or visco-elastic padding) also can help. Wherever possible try not to get the socks wet.
Things to avoid include coating the feet with petroleum jelly or another such lubricant in the belief these helps decrease surface friction, However, thick lubricants also prevent sweat evaporation and increase skin hydration making the vulnerable areas more prone to blister. Coating the feet with astringents such as surgical spirit dehydrates the skin which may result in cracking (fissures) and or blisters. By preparing yourself for the event this usually means blisters are dealt with well before competition. To prevent other sports injuries always warm up and warm down prevent other sporting injuries.