Marathon Blisters Related to Pronation?

QUESTION:

Hi Doc,

I have just finished a marathon qualifier for an ultra coming up here in South Africa. I have always been pretty neutral footed, but with the tendency to pronate slightly. I have always had the odd blister after a very long run, but lately they seem to be worse and I am wondering if I am beginning to pronate more (can this happen over time?). I have taken a photo of some blisters that occur after a marathon. I don't like to get rid of them, I sorta let them callous for the season so its not so sore :-). Should I try pronation shoes? What are your thoughts? I use Nike Pegasus +28's. Really hope you can shed some light on this for me :-) 

Many thanks

ANSWER:

Blisters that pop up anywhere on the foot during/after a marathon are always the result of excessive pressure and friction. With excess friction the underlying layers of the skin begin to separate. Fluid accumulates and collects between the dermis and epidermis creating the fluid filled bubble that runners know as a blister. In the pictures here we can see that one blister has clear fluid and the other is dark. The dark blister implies that this is a collection of blood. This kind of blister is of course often referred to as a "blood blister." 

A blood blister insinuates more pressure or increased trauma, not just friction.

The location of the blister is important and helps a podiatrist figure out the cause. These blisters and calluses forming at the inside of the big toe joint. The medical term for this location is the "medial and plantar-medial aspect of the first metatarsophalangeal joint." 

All runners know the basic causes of blisters.  To be clear we will review:

1. Running shoes that are loose. The feet slide around with every foot strike and push off while running. The result of 26.2 miles of this is excessive friction producing blisters. 

2. Running shoes that are too tight. The feet are compressed against the inside of the shoes, increasing the risk of excess friction (with increased pressure) at parts of the shoe that move (such as the tips of the toes or ball of the foot where the break in the shoe occurs).  

3. Wet feet. Think twice about running through those garden hoses on the marathon course. Moisture in the skin can weaken the structure between the layers of skin, making blisters form with less friction that usually required. 

4. Starting and Stopping too much. If you are running with a walk/run approach, all of the starting and stopping actually takes more force (and produces more friction) than running at an even pace. This can increase your risk of blisters.  

There are other certain circumstances that can contribute to blister formation at the medial big toe joint. 

1. Pronation. As the foot pronates, the foot rolls inward, unlocking the joints in the mid-foot. The first metatarsal bone gets pushed up by the ground and the running shoe effectively twists right around the inside of the big toe joint. This of course creates excess friction and stimulated the formation of blisters during longs runs such as marathons. 

2. Bunions. Same forces at work as in excess pronation, with the added pressure at the bunion stick out and presses against the inside of the shoe. 

Solutions:

1. Blister-prevention socks that have 2 layers that can glide past each other. In effect, you beat up the socks instead of the skin.

2. Custom orthotics or over-the-counter inserts that support the foot, stabilize the subtalar joint and decrease pronation. If properly fitted and constructed, inserts can slow the pronation that contributes to the problem. 

3. Motions control running shoes. Stability running shoes decrease pronation with aggressive medial posting on a stable platform.  They are heavier, and stiffer. Beware-if you have high arches they can increase your risk of shin splints and stress fractures. 

4. Build mileage gradually. This gives the skin a chance to toughen up and form protective calluses without blistering.  

When in doubt. See a local podiatrist for a complete evaluation, running shoe analysis and gait exam to assess your running biomechanics. 

Dr. Christopher Segler, DPM a marathon runner, podiatrist and 10-time Ironman Triathlon finisher who is is Board Certified, American Board of Podiatric Medicine.  He believes the best podiatry practice combines cutting edge technology with the old-school convenience of house calls. He makes podiatry house calls for runners in San Francisco, Palo Alto, Sausalito, Pacifica, and Corte Madera. He also does remote consults for runners who live outside of the United States. If you have a question, you can reach him directly at 415-308-0833. You can learn more about running injuries at www.DocOnTheRun.com 

To Pop or Not To Pop: Blister treatment for runners explained by San Francisco's Running Podiatrist

Dr. Oz recently ran a segment on his television show instructing his audience to pop blisters whenever they occur on the feet. He went on to explain that if you successfully get all of the fluid out, the top layer of the blister will form a adhere down to the tissue underneath and create a "biologic dressing."

While this may be sound advice for a typical healthy woman who gets a blister from a new pair of high heels, the real question for Bay Area runners is: "Should I drain a blister" if I am a runner training for a race such as a marathon or triathlon?

The best answer is "sometimes you should, and sometimes you shouldn't."

The medical term for the type of blisters on the feet when running are "friction blisters." Blisters on the feet occur from a combination of skin friction and pressure. When your foot slides around inside the running shoe, you get friction. Rubbing the skin over and over in one spot (such as the back of the heel or ball of the foot) causes the layers of the skin to begin to separate. Fluid then seeps into this newly created space between the layers forming the blister.

Keep irritating the area and the blister continues to get bigger. Even if you simply continue to apply pressure to the blister (like pressing it against the heel counter inside the running shoe) it will continue to get bigger. This is because the fluid will try to spread outward and keep separating the skin layers. Then even more fluid seeps in to make the blister bigger.

If you keep rubbing the blister long enough, the skin on the top of the blister will tear effectively popping on its own. The blister then starts to ooze relieving the pressure as the fluid leaks out. So should you take charge and drain it yourself?

What sports medicine podiatrists know about blisters in runners is:

1) small non-painful blisters heal quickly
2) large painful blisters hurt less if drained and not irritated, but hurt more and have a slightly higher risk of getting infected if they are drained and the activity (such as running) is continued
3) blisters with the overlying blister roof removed will heal, but hurt more initially

So If you are runner with a small blister on a toe and it doesn't hurt don't drain it. It will heal quickly and has a very low risk of infection. If the fluid can't drain out, bacteria can't get in. If you have a blister that is small, put a felt pad around the blister. You need a donut shaped or U-shaped pad for this to work. You need to put the pressure around the blister and not on the blister. This will stop all of the rubbing that could make the blister get bigger. It will also stop the blister from hurting.

If you running a marathon or competing in an Ironman triathlon and get a huge blister that makes it hard to walk after the race, drain it. You can do this by poking a small hole at the edge of the blister. Heat the needle or soak it in rubbing alcohol. This will sterilize the needle so that you don't introduce any infection causing bacteria when you puncture the blister.

Cover the blister with a bandage that will soak up the fluid as it continues to leak out. If the fluid starts to build up again, then repeat this process and drain the fluid again. Marathon runners with big blisters may have to do this a couple of times. The blister can be quite irritated after running 26.2 miles.

So what are the "exceptions to the rule" about popping or draining blisters in runners?

1. If you notice the blister at mile 13.1 and still have another half-marathon to go, don't pop the blister. This is where the advice from Dr. Oz doesn't fit with runners. If you drain the blister on your heel then continue to run, more fluid will seep under that skin. The skin will slide back and forth. If the drained blister skin slides around, it can't work as a "biologic dressing" because it never has a chance to stick to the underlying raw area. The roof of the blister may also tear. That is what happened in the blister pictured above. All of the rubbing of the heal inside the running shoe caused the blister to rip open. If the roof of the blister tears, it needs to be removed (called "de-roofing" by podiatrists).

If the blister is drained, you need to secure the overlying skin in place with a dressing. Wait until the race is over. If you drain it mid-race it will hurt like hell, there is a higher risk of infection and it will take longer to heal. You also need to wear a pair of shoes that won't rub on the raw blister after it has popped. So once you drain the blister, apply a dressing that will hold the skin securely in place. Change the dressing daily. Studies show that hydrocolloid dressings works best to bake blisters heal fastest. But there is NO evidence than antibiotic ointment helps blisters heal any faster.

2. All blisters should be drained, completely de-roofed and treated by a podiatrist if you are diabetic. The risk of infection is much higher in diabetics. A blister anywhere on the foot in a diabetic runner is a medical emergency. I have personally performed many amputation on diabetics where a blister became hugely infected and spread to the underlying bone. Seek immediate medical attention if you have diabetes and a blister anywhere on the foot, heel or toes.

Although it is easy to prevent blisters, they still often occur in runners. In fact research shows that blisters on the feet are by far the most common running injury reported among marathon finishers. If you get a blister on the feet, treat it right and it will heal quickly so you won't have to miss much training at all.

Dr. Christopher Segler is a sports medicine podiatrist in San Francisco with a focus on runners. He is also a marathon runner and Ironman triathlete himslef. He makes house calls all over the Bay Area to treat running injuries like blisters, stress fractures and Achilles tendonitis. If you have a question about a running injury you can email him or call (415)-308-0833 to reach him directly. For the best source of running injury prevention information in the San Francisco Bay Area, visit MyRunningDoc.com or AnkleCenter.com.

Most Painful Running Injuries

The poll results are in! The February 2009 issue of Runner's World Magazine reports on the most painful afflictions and injuies that plague runners.

...and the winner is....SHIN SPLINTS!

Thats right, that aching pain in the front of the leg came out as the most painful running ailment based on 2,263 respondents of the Runner's World poll.

The other top finishers from the complete results were:

Shin Splints 36%
Side Stitches 20%
Chafing 13%
Blisters 12%

We will discuss each of these running injures...and how you can beat them, instead of them beating you over the next few days.


Dr. Christopher Segler is an award winning foot surgeon and Ironman Finisher who treats elite athletes. His podiatry sports medicine practice is at the Doc on the Run Podiatry Sports Medicine House Calls in San Francisco. To learn more about increasing your speed and avoiding running injuries like tendonitis, shin splints and stress fractures, you can register for a FREE membership and copy of his monthly newsletter “Finisher’s Circle” by visiting http://www.AnkleCenter.com .