Blisters are a common foot injury that are caused by repeated friction or trauma to the skin and can vary from superficial to full-thickness (through the deeper layer of skin to underlying tissue or bone).
Blisters form as the body’s response to cushion the area from further damage as it heals. If the blister remains intact the body will gradually absorb the fluid and flatten after a week or two. If the blister is a full thickness it may be filled with blood and take longer to heal.
Causes of Blisters:
- Poor fitting footwear (too tight or too loose).
- Shoes without a fastening (velcro/laces or strap) to hold the foot in the shoe and prevent friction and rubbing.
- Not wearing in new footwear gradually.
- No socks with shoes.
- Over training or high impact pressure on feet during sport and/or running.
- Fungal skin infection (pustular tine pedis).
- Allergic reaction or viral skin infection.
- Burns and scalds.
Symptoms of Blisters:
- Fluid filled sacks that form over areas of friction.
- Pain, burning, redness and increase warmth in area of friction.
- Infection may present if the skin is broken and first aid is not applied.
- Callus may form over blister areas.
Treatment for Blisters:
- First aid must be applied regardless if the blister is intact or broken (e.g Iodine and a simple dressing).
- In some cases the blister needs to be cut and released if it is causing too much pressure. This should be done by a podiatrist with a sterile instrument and in the appropriate location of the blister to allow fluid to be removed most effectively and with minimal trauma under the weight bearing foot.
- Padding and offloading the area to prevent further rubbing or friction.
- Antibiotics if infection is evident.
- Antifungal treatment for tinea.
- Antivirals or treatment for underlying allergy.
- The best treatment for blisters is prevention.
Prevention of Blister:
- Wearing socks with shoes.
- Tapes and dressings to protect the area.
- Blister sprays.
- Appropriate fitting, supportive footwear (which may need to be assessed).
If the blisters are recurrent you may need orthotic therapy or footwear modifications to prevent increased pressure and friction in the effected area.