Foot Conditions A-Z
Nearly everyone gets blisters from time to time. Whether they form on the hands from hard work, or whether they form on the feet from shoes or just going barefoot, they're an aggravation and a potential gateway to more serious conditions if left untreated. Here's how foot blisters happen and how to prevent them.
When the outer layer of skin (epidermis) is subjected to repeated contact friction or shear forces (shear is a tearing process in the skin caused by tissue layers moving in opposing directions), a blister typically results. The friction or shear forces cause tears in the second and third layers of the skin, and pressure forces fluid into the open spaces. Fluid fills up the open spaces in the deeper layers of the skin, while the top layer remains intact. In situations where blood vessels in the skin also break, blood drains along with the fluid, forming what are often called "blood blisters."
Blisters on the feet typically result from repetitive stress to exposed areas, particularly those that protrude or are raised, such as bunions and hammer toes, and on normal weight-bearing areas (pressure points).
The main culprit is an improperly fitted shoe or boot. Sometimes the design—for example, a too narrow toe box, a too wide heel area, raised seams in the shoe or boot lining--can lead to blisters even when shoes and boots are properly fitted.
Blistering is more frequent and more severe when the feet get wet, which softens the skin, making it much more vulnerable to friction and shear forces. Most friction blisters tend to form in the heel area, where friction from movement of the heel causes the skin to tear.
Blisters also are commonly found:
- on the sides of the big toe and the fifth (“pinky”) toe, when the toe box of the shoes or boots “squeeze” the forefoot
- on the bottom of the toes, where friction from toe off (the final stage of the running gait, where the toes propel the runner forward as the foot is pushed off from the ground) occurs
- on the tops and tips of the toes in situations such as hammer toes, where the feet or toes have changed shape due to other issues
- on the tops of the toes, from raised seams in socks
- on the sides of the heels, when the heel area of the shoe or boot rubs and causes friction
Prevention and Treatment
As a preventive strategy, IPFH suggests the following:
Wear only properly selected and fitted, as part of an integrated approach, padded socks with shoes with non-slip outsoles and any inserts or orthotics prescribed or recommended by a doctor or foot health professional.
Infection is a danger if the blister breaks or if you deliberately break the skin (generally, it is not a good idea to puncture it by breaking the skin, although there are some exceptions). If the skin does break, use antibiotic ointment to help prevent infection.
Consider puncturing if the blister is preventing you from walking to safety when you are under threat - for example, if you are backpacking in an area that requires you to move from your current position to a safer location (during a storm, for example) and your ability to walk is hampered.
If you decide to puncture, do it as soon as possible after the blister occurs, and definitely within 24 hours:
- Sterilize a needle with rubbing alcohol or by placing the needle in a flame.
- Pop the blister from the side (don’t go straight in), and don’t twist the needle.
- Make a few holes in different sides of the blister.
- Carefully squeeze out the fluid.
- Once the fluid has drained, seal the blister with a glycerin gel lubricant, apply an antibiotic ointment and cover with a bandage.
Do not pop blood blisters because they most likely have penetrated multiple layers of skin.
People with diabetes and / or neuropathy should never attempt to puncture or break blisters, but should see a medical professional such as a podiatrist or dermatologist.instead.
Over the longer term, blisters can cause changes in your walking or running gait that can lead to more serious muscle, tendon, ligament and joint problems. Rarely, they can be a symptom of more serious conditions such as the hereditary condition, epidermolysis bullosa or erythema multiforme, a hypersensitive reaction to infections or drugs.
Allergic reactions--for example, after exposure to poison oak or sumac--also can cause blisters that are accompanied by inflammation / redness and itching.
Always talk to your doctor if you have soreness, pain, redness, swelling or other indications of foot problems that persist for more than a few days.
See also IPFH's information on toe blisters.