Advice on Foot Care

I worked at the Western States 100 finish line in Auburn this past weekend, giving the finishing runners needed foot care. The run is conducted along the Western States Trail starting at Squaw Valley, California, and ending in Auburn, California, a total of 100 miles. The trail ascends from the Squaw Valley floor to Emigrant Pass and then follows the original trail used by the gold miners. The runners head south and west and climbs over 18,000 feet during the run and descends almost 23,000 feet before reaching Auburn.

The most common foot problem is blisters. Blisters on the toes are common, especially the 5th toe and under the great toenail. Other common places for blisters are the heel and under the ball of the foot. Black toenails are standard for many ultra runners, and losing a toenail during training or after the race is not uncommon. The Western States run is unique in that there is a lot of descending and climbing in and out of the canyons. The decents are steep and the trail is rocky and loose. This causes more jamming of the toes against the front of the shoes and this friction causes blisters and excess pressure on the toenails.

The great toenail is susceptible to excess shoe pressure because of it’s size, location and function of the great toe joint. Excess pressure and friction cause small breaks in the blood vessels below the nail and the area below and around the nail can fill with blood and fluid. Most runners know this as a blood blister under the nail. The medical term is subungual hematoma. The treatment is to clean the area with antispetic or betadine and then lance the blister. It is best to make a small puncture area right under the nail and let the fluid drain with gentle pressure. Wrap the toe with a non-stick wrap and then soak in warm water and epsom salt for 15-20 minutes twice a day until the area is dry. Placing tape over the nail is not recommended (unless the toe is treated during the race) as there is a good chance the nail can be pulled off when the tape is removed. When the blood blister extends under and around the nail, there is a high chance the nail will be lost, but it does not necessarily need to be removed. If the area develop redness, swelling or pus, then this is a sign of infection and the runner needs to seek immediate medical attention.

A blister (bulla) develops in response to friction, shearing stress and abnormal pressure. The outer layer of the skin (called the epidermis) separates from the lower layer of skin (called the dermis) and fluid collects between these two layers. This fluid offers protection and shock absorption for the lower layers of skin. A new layer of skin will grow underneath the blister. A blood blister occurs when there enough friction or trauma to cause damage to blood vessels which leak blood in between the skin layers. The body fluid and blood combine to form a clear red fluid. In some cases, direct trauma causes the blood vessels to break and cause only blood to fill in between the layers of skin. Blood blisters can be drained in the same way as regular blisters. The treatment we generally do is to lance the blister with a sterile blade after cleaning the area with an antiseptic cleaner. The size of the hole should be about 1 mm, large enough to allow the fluid to drain. A small hole, like a needle stick, generally closes up and refills quickly. Gentle pressure should be applied to drain the fluid and a non-stick dressing should be applied and the area soaked as soon as possible in warm water and epsom salt to help pull any excess fluid out. As soon as the area has dried, thin moleskin or mole tape can be applied and left on until it falls off. Do not apply an adhesive dressing when the top layer of skin is thin and loose. Because the fluid accumulates between the two layers of skin and most blisters do not penetrate the dermis, the infection rate is low. But, it is always wise to clean the area using an antiseptic cleaner and watch for signs of infection (redness, swelling, streaking, pus, increases in pain) while the area is healing.

For blister prevention, appropriate shoe fit is important. I spoke with one of the top 5 finishers after the race. He said that he finally figured out how to keep his feet from blistering. He stops and re-ties his shoes during the race to keep them tight enough to prevent the foot sliding back and forth in the shoe. Preventing sliding will reduce friction and help prevent blister formation. In a race as long as the Western States, the shoes will loosen during the run, increasing sliding within the shoe, friction and shearing. But, most of the runners I spoke with said they developed their blisters within the first few hours of the race. This is usually due to problems with shoe fit or inappropriate socks.

In the picture to the left, a runner placed a second skin type blister patch around his 5th toe at the beginning of the race to prevent blister formation. This did a great job of keeping the moisture and heat around his toe, which resulted in separation of the two layers of skin. When he tried to pull the patch off his toe, it pulled the top layer of skin and nail off as well.

The second skin type blister patches are great for the heel and the ball of the foot, but they are too occlusive and thick for the toes. It is better to place sports tape, micropore tape or thin moleskin on the toes after applying a sports tape adherent for prevention. The most popular blister kit the runners had at the race was from Zombie Runner. I appreciated those runners who allowed me to use some supplies from their blister kits. I treated so many runners that supplies were running low by the end of the race.

After the 24 hour mark at 5:00 am, many of the finishers curled up in sleeping bags to get some much deserved rest. Congratulations to all the runners!

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