Health Topic

Blisters

Blisters are fluid-filled sacs on the outer layer of your skin. They form because of rubbing, heat, or skin diseases. Learn about how to prevent them.

Reviewed Reviewed by a registered pharmacistGeneral information

Also called: Bulla · Vesicle

Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.

About Blisters

Blisters are fluid-filled sacs on the outer layer of your skin. They form because of rubbing, heat, or diseases of the skin. They are most common on your hands and feet.

Other names for blisters are vesicles (usually for smaller blisters) and bulla (for larger blisters).

Blisters often happen when there is friction - rubbing or pressure - on one spot. For example, if your shoes don't fit quite right and they keep rubbing part of your foot. Or if you don't wear gloves when you rake leaves and the handle keeps rubbing against your hand. Other causes of blisters include:

  • Burns
  • Sunburn
  • Frostbite
  • Eczema
  • Allergic reactions
  • Poison ivy, oak, and sumac
  • Autoimmune diseases such as pemphigus
  • Epidermolysis bullosa, an illness that causes the skin to be fragile
  • Viral infections such as varicella zoster (which causes chickenpox and shingles) and herpes simplex (which causes cold sores)
  • Skin infections including impetigo

Blisters will usually heal on their own. The skin over the blister helps keep out infections. You can put a bandage on the blister to keep it clean. Make sure that there is no more rubbing or friction on the blister.

You should contact your health care provider if:

  • The blister looks infected - if it is draining pus, or the area around the blister is red, swollen, warm, or very painful
  • You have a fever
  • You have several blisters, especially if you cannot figure out what is causing them
  • You have health problems such as circulation problems or diabetes

Normally you don't want to drain a blister, because of the risk of infection. But if a blister is large, painful, or looks like it will pop on its own, you can drain the fluid.

There are some things you can do to prevent friction blisters:

  • Make sure that your shoes fit properly
  • Always wear socks with your shoes, and make sure that the socks fit well. You may want to wear socks that are acrylic or nylon, so they keep moisture away from your feet.
  • Wear gloves or protective gear on your hands when you use any tools or sports equipment that cause friction.

It sits within Skin, Hair and Nails.

When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.

Research on Blisters

118 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.

What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.

Research currently under way

Research already completed

Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.

Where to read more

Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.

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Clinical Trials

Medical subject headings

Clinicians and researchers index this subject under Blister. These are the terms to use when searching medical literature.

This page is built from the MedlinePlus health topic record for Blisters, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.