Shearing forces within layers of the skin cause irritation. If this irritation continues long enough the softer, deeper layers of skin breakdown and weep plasma. This process builds and forms the lesion that is commonly known as a blister. These causative shearing forces can arise from such things as biomechanical abnormalities (abnormal pronation), poorly fitting footwear and foreign bodies in the shoes. Shearing from skin on skin is one of the most common causes of blistering, usually between the toes where moisture, heat and compression (from footwear and sometimes swelling) can build up over time.
Causes and Treatment
Treatment of blisters usually consists of making the area comfortable so healing can begin, and then removing the predisposing factors that cause the blisters.
Initial treatment often involves draining the blister and leaving the skin covering attached (this will limit the amount of discomfort). If the skin covering is removed the amount of pain experienced will usually be increased. The blister can then be dressed with a sterile dressing.
Following the initial treatment, the correction of the predisposing factors can begin. This may include:
- correct socks for your activity, foot glove socks are best for avoiding toe blisters
- correctional orthotics to limit excessive pronation and improve overall foot function
- checking footwear for foreign bodies like sand, grit or irritating stitching
- fitting footwear correctly
Preparing for your Event:
- Use smooth surface, synthetic (CoolMax or Teflon) double layer socks for activities such as running or trail walking. Double-layer socks limit the friction in between the two layers of socks instead of between the skin and the sock.
- Toe socks avoid blisters forming between the toes.
- Take spare socks and change them regularly.
- Avoid wet socks or shoes. If you sweat too much, use antiperspirant deodorant or talcum powder but be careful as talcum powder can become abrasive if it’s used in excessive amounts.
Wearing-in new shoes is very important. Take your time gradually increasing your activities in them, even swap back to your old shoes frequently within the first week. The shoe needs to get used to you but more importantly you need to get used to the shoes.
Remove heavy callus before any activity event that may be above average. A light callus protects your feet from blisters so do not shave off callus excessively. This is best performed by a podiatrist. Condition your feet to their environment. Build up your distance or intensity gradually over weeks or months prior to the event. This is imperative for the skin and also the musculoskeletal system in avoiding injury and overuse. Surgical spirits (Isopropyl Alcohol) can speed up the conditioning of skin to resist friction.
- Stop and inspect the painful area and eliminate any obvious causes.
- If you have sensation loss in your feet due to diabetes or other peripheral neuropathies allow time to stop and inspect your feet to ensure they aren’t damaged. Reduce friction in the prone areas by padding with suitable materials like felt or fleecy padding or taping with hypoallergenic tapes like Hypafix, Fixomull or anything similar.
- Alternatively using lubricating agents such as Body Glide or Sorbolene if you’re close to the finish line. Do not use lubricants if sand or grit is likely to enter the area as creams typically soften the skin and this will encourage the abrasive agent to imbed the skin.
Some events have stops especially for blisters and feet problems. These are usually manned with at least one podiatrist. Alternatively or additionally there are first aid stations which are setup to provide general medical aid. Make use of these stations when you see them, even if you don’t have an immediate need as it is much better to prevent a problem than treat it. Use the stop as a place to inspect your feet and if there is a problem the podiatrist will be right there to help you.
If a blister is painful the podiatrist at the blister station will inspect it and treat it accordingly. Treatment is always an option and you may wish to discuss with the podiatrist what your options are. Treatment of painful blisters can involve:
- Swabbing the area with disinfectant and a drying agent.
- Taping and padding
- Lancing or draining the blister if it is fluid filled
A blister goes away on its own, if it is not hurting, don’t hurt it.
In case it is painful and hurts while walking, try draining it using a sterile needle (this is best performed by your podiatrist). Steps for this are:
- Wash your feet and dry them properly.
- Apply a disinfectant over the surface. Make a hole in the blister using the sterile needle.
- Squeeze the blister to push out all the fluid.
- Do not remove the overlying skin, for it aids in healing by protecting the new skin forming underneath.
- Clean once again with a disinfectant and cover the area with an antibiotic ointment.
- Apply sterile bandage. Give it rest and keep it dry until it heals.
When to seek medical attention:
- If you are suffering from a disease that has weakened your immunity and healing capacity such as diabetes, it is better to get it checked and treated by a podiatrist.
- If the blister becomes excessively painful, there is redness and swelling, with or without a yellow or green discharge, it might be infected and you should seek immediate medical care.