Medical Considerations for Blisters
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 ivy, 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.
Reviewed by: Robert P. Thompson, C.Ped, IPFH Scientific Advisory Board
Last updated: June 11, 2015