What are blisters?

Blisters are fluidfilled 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).
What causes 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

What are the treatments for blisters?

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.
Can blisters be prevented?

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.