What are blisters?
Your skin consists of three layers: the epidermis, the dermis and subcutaneous (below the skin) fat. A blister forms under the epidermis as a fluid-filled sac. Typically, it may be filled with clear liquid or blood, depending on the injury that damaged your skin.
Blisters may be painful or itchy. If a blister gets infected, it will fill with milky-white pus. Blisters most often show up on the feet or hands, but they can appear anywhere on the body.
Symptoms and Causes
What causes blisters?
You can get blisters in several different ways, including some diseases. The most common types of blisters include:
- Blood blisters: You can get blood blisters when something pinches your skin. Instead of clear liquid, blood floods the area from broken blood vessels and damage to the lower layers of the skin. The blood pools and forms a blister.
- Friction blisters: Caused by rubbing on the skin, friction blisters form when clear fluid builds up in the upper layers of skin. Many people get friction blisters from walking too much in poor-fitting shoes or by not wearing socks. You can also get them on your hands from holding things like shovels or other tools.
- Heat blisters: You can get these blisters from burns or sunburns. They may also form after you warm up from frostbite. Blistering skin is part of a second-degree burn.
Diagnosis and Tests
Do I need to have a doctor look at my blister?
Blisters generally do not need a healthcare provider to look at them. There are no tests or diagnostics for blisters.
If a burn or frostbite caused your blisters, a healthcare provider may need to treat the underlying cause. You may also need to see your provider if a blister shows signs of infection, such as:
- Pus (yellowish or greenish discharge).
- Hot or painful area around the blister.
- Red streaks around the blister.
Management and Treatment
How do I treat blisters?
Blisters generally heal on their own within a few days. You can do a few things at home to make them more comfortable:
- Wash the area gently with a mild soap.
- Apply antibacterial cream or ointment.
- Cover the blister with a bandage or gauze.
Be sure to change the bandage at least once a day. And resist the temptation to pop or break a blister or peel it off. The skin on the blister protects deeper layers of skin from infection.
How can I prevent a blister?
You have several options for preventing blisters. Most involve preparation and caution. Preventing blisters depends on the type of blister:
Friction blisters: Friction blisters result from repeated rubbing. To prevent them:
- Make sure your shoes fit well and do not rub.
- Break in new shoes before wearing them for extended periods.
- Wear gloves to protect your hands if you plan on doing a lot of manual labor.
- Wear properly fitting clothes to prevent chafing that can lead to blisters on other parts of your body.
Blood blisters: These blisters usually develop when something pinches part of your skin. They typically happen on the hands. It’s harder to prevent them, but take these steps:
- Stay alert when using tools or things that can pinch.
- Wear gloves when working with pruners, strong pliers or in other tight situations.
Heat blisters: Heat blisters can result from a burn or when your skin gets too hot as you recover from frostbite. To prevent them:
- Use sunscreen if you plan to be in the sun for an extended period.
- Be extra careful when handling hot items or working around a fire.
- Wear weather-appropriate clothing to avoid frostbite. If your skin gets frostbitten, slowly raise your body temperature using lukewarm water.
Outlook / Prognosis
How long does it take blisters to heal?
Most blisters heal naturally on their own in a few days. Be sure to bandage the blister and wear different shoes while it heals. If you have blisters from burns or frostbite, or you think your blisters could be infected, consult your healthcare provider.
When should I see a doctor about blisters?
You should see a healthcare provider if your blister does not improve after a few days. You should also see a provider if the blister appears infected. If it is infected, your skin will be red and swollen. The blister fills with a white or yellowish fluid rather than a clear fluid or blood.
A note from Cleveland Clinic
Blisters are pretty standard, but it doesn’t make them any less painful. For runners, hikers and anyone on their feet a lot, blisters can be a major pain. If you get a blister, it should get better on its own in a few days. If your blister appears infected, see your healthcare provider.
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