Blisters are raised or loose areas of skin in which fluid accumulates under the outer layer. A blister may not be painful at first, but if the outer layer of skin—the epidermis—is opened, the sensitive skin underneath can become quite painful and may also get infected.

Blister Image - Masterfile

Symptoms of Blisters

  • Fluid-filled, raised areas on the skin that are often tender to the touch and sometimes filled with blood

What Causes Blisters?

Blisters have many causes, including burns, cold sores and allergic reactions to plants or insects.

But the most common non-medical cause is friction or pressure from ill-fitting shoes, socks, or stockings (either too big or small) that rub against skin. Going without socks or stockings in normally well-fitting shoes can also blister heels and toes, particularly in hot weather, when feet are likely to swell and sweat. Sandals and other shoes with straps are particularly likely to blister bare skin.

Blisters also may form on the hands when using a shovel, hammer or other tool and even when riding a biking, especially if protective gloves are not worn.

What If You Do Nothing?

If it’s a small blister, it will heal by itself if you eliminate the pressure that is causing it. Just make sure it stays clean.

Home Remedies for Blisters

If the blister is less than an inch across, don’t break it open or try to drain it. Not only is the skin underneath extremely sensitive, but it can also become infected. If necessary, take the following steps.

  • Relieve pressure. If the blister is in a weight-bearing spot, cover it with a moleskin pad with a hole cut in the middle.
  • Relieve pain. If you have a large blister that hurts when you walk on it, you may want to puncture it. First wash the area, then make a small hole near the edge of the blister with a sterile needle or tip of a scissor (To sterilize the needle or scissors, place the tip in alcohol or hold it in a flame for a few seconds and cool). Don't remove the "roof" of skin. Gently squeeze out the liquid and cover it with a tight sterile bandage; try to keep it dry.
  • Cleanse and protect. If the blister breaks, wash it with soap and water and protect it with a light bandage.

Avoiding Blisters: The Fitted Shoe

Shoes that don't fit well are a major cause of blisters. However, this all-too-common problem can be avoided by following these simple steps. Start with proper measurement: the shoe store’s metal Brannock device is more accurate than a wooden ruler. Always put your full weight on the foot being measured. Try the size that fits the larger foot.

Sizes indicate very little: size 8 1⁄2 C in one brand may be a 9 B in another. Imported shoes are likely to run small.

Follow these other tips:

  • Try to shop in the middle or towards the end of a normal day, not early in the morning, since your feet swell as the day progresses owing to friction, heat, and use.
  • Wear the kind of socks or stockings that you intend to wear with the shoes. Avoid socks and stockings that constrict your feet or bunch up.
  • When testing new shoes, stand on one foot at a time. Wiggle your toes. Stand on tiptoe. The shoe should bend where your foot bends.
  • Never buy a shoe with the idea of breaking it in over a period of time. Your foot may alter in an uncomfortable shoe, but the shoe won’t.
  • Check to see that you have one-half inch of space between the end of your big toe and the tip of the shoe.
  • Make sure the widest part of your foot—the metatarsal arch—fits comfortably in the shoe.
  • Wear gloves to protect your hands whenever necessary.

Blister Prevention

  • Buy shoes that fit. This is your first line of defense.
  • Keep your feet dry. Cotton or woolen socks, though able to absorb moisture better than nylon, still hold moisture against your skin, thus increasing the risk of blisters. Athletic socks made from a variety of polyesters, such as polypropylene, acrylic, or Capilene, draw moisture away from your feet so that it can evaporate. Foot powders also help absorb excess moisture.
  • For hiking, an antiperspirant may help. If your feet tend to sweat heavily and you are prone to blisters, you can try an aluminum-containing antiperspirant to keep feet super dry. In a study of West Point cadets, the cadets found that applying such an antiperspirant daily for three days before a long hike significantly reduced the risk of blisters. However, half the cadets experienced skin irritation from the antiperspirants they used, so if antiperspirants irritate your underarms, this approach isn't for you. Otherwise, try it using a roll-on or stick product.
  • Protect blister-prone areas. Use foot powder, breathable adhesive tape (sometimes labeled “first aid”), moleskin, “Second Skin” (a slippery pad that absorbs friction), or petroleum jelly to reduce pressure and friction. If you typically develop blisters on your hands after using tools or sports equipment, don’t forget to put on gloves before beginning your activity.

Beyond Home Remedies: When To Call Your Doctor

Contact your physician if a blister shows reddening, swelling, or pus—each is a sign of infection. Also contact your physician if you have a history of diabetes or circulatory disease and have developed a blister.

What Your Doctor Will Do

If infection is suspected after a close examination, your physician may prescribe an antibiotic medication.


The Complete Home Wellness Handbook

John Edward Swartzberg, M.D., F.A.C.P., Sheldon Margen, M.D., and the editors of the UC Berkeley Wellness Letter

Updated by Remedy Health Media

Publication Review By: the Editorial Staff at

Published: 11 Aug 2010

Last Modified: 02 Sep 2015