A blister is a fluid-filled bubble that forms on the surface of the skin, typically caused by friction. Foot blisters develop when the skin rubs against shoes or another surface, creating a tear in the epidermis. This causes a space to form between the layers of skin, which then fills with fluid.

Causes of Blisters

Blisters are most commonly caused by friction, heat, inflammation, or moisture. Friction blisters typically form when your feet rub against shoes. To prevent them, it’s a good idea to gradually break in new shoes or cover areas of skin that tend to rub against footwear.

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Common causes of blisters include:

  • Allergic reactions
  • Autoimmune diseases
  • Chemical injuries
  • Contact dermatitis
  • Frostbite
  • Fungal infections
  • Inappropriate footwear
  • Insect bites
  • Minor burns

Blister Symptoms

Blisters have a characteristic appearance: a bubble of skin filled with clear fluid. They can range in size from a few millimeters to up to an inch in diameter.

Blisters may come with pain, warmth, redness, and itching. Some may be tender to the touch, while others are more painful. If the fluid in the blister is yellow or green, it may indicate an infection.

Blister Treatment

Most blisters don’t require a doctor’s care. New skin will develop beneath the blister, and the fluid will eventually be absorbed. It’s best to avoid puncturing the blister, as the skin covering the blister acts as a protective barrier, reducing the risk of infection.

If a blister becomes painful and interferes with walking, you may need to drain the fluid while leaving the outer layer of skin intact. Clean the area thoroughly and use a sterilized needle to make a small hole in the blister. Gently squeeze out the fluid, apply antibiotic ointment, and cover it with a bandage.

Contact a physician if signs of infection appear, such as increased redness, swelling, or pus. If you have diabetes or any condition that affects circulation, consult a doctor before treating a blister yourself.