A blister is a fluid-filled bump on the skin.

  • Causes

    Blisters have many different causes. These may include::

    • Friction or constant pressure, such as from wearing a tight-fitting shoe or gripping a tool

    • Second-degree burns, including

    • Viral infections, such as
      , or herpes

    • Bacterial infections, such as

    • Fungal infections, such as
      athlete’s foot

    • Contact dermatitis, such as
      poison ivy, oak, or sumac
    • Allergic reactions
    • Reactions to certain medications
    • Certain cancers

    • Blistering diseases, such as

    • Autoimmune disorders, such as
    • Insect bites
    • Scabies

  • Definition

    A blister is a fluid-filled bump on the skin.

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  • Diagnosis

    Your doctor will ask you about your symptoms and medical history. A physical exam will be done. Blisters may be diagnosed on appearance. The cause can be determined by the activity you were doing when the blisters appeared.

  • Prevention

    To help reduce your chance of getting blisters, take these steps:

    • Wear shoes that fit properly.
    • Always wear socks with your shoes.
    • Wear sports socks when exercising or participating in sports.
    • Use gloves or protective padding when working with tools.
    • Wear a hat, protective clothing, and sunscreen when out in the sun.
    • Wear sandals in public showers to protect your feet from athlete's foot.
    • Wear long shirts and pants when working outside to protect yourself from poison ivy.

  • Risk Factors

    Factors that increase your chance of getting blisters include:

    • Wearing ill-fitting shoes
    • Repetitive work with hand tools
    • Getting a sunburn or frostbite
    • Severe skin swelling, especially of the legs

  • Symptoms

    Blisters may cause:

    • Fluid-filled bump on the skin, which is often round
    • Fluid is usually clear, but may be bloody, cloudy, or purulent

  • Treatment

    A blister will often heal without treatment. You may need treatment for a condition that is causing the blisters.

    Some general tips for treatment include: