A blister (bulla) is caused when the outer layer of the skin separates from a layer of skin below, creating a collection of fluid between the layers. Blisters can be caused by chemical means, such as an allergic reaction; physical injury, such as from heat, frostbite, or friction; or from a disesease.

If the blister has been caused by a burn, see the Burns, First Aid write-up via the Disease List. If the blister has been caused by frostbite, see the Frostbite, First Aid write-up, which can also be found via the Disease List.

First Aid For Blisters
Blisters often go away on their own without needing any care, and the skin over the blister is its best defense against infection. If the blister is large or painful, however, you can drain the blister in such a way as to relieve the discomfort and hopefully avoid infection. Note: Blisters that look like they will pop on their own should be drained, unless the blister looks infected or you have a fever; multiple, grouped blisters; diabetes; or poor circulation.

1. Clean your hands and the affected area with soap and warm water.
2. Apply rubbing alcohol to the affected area.
3. Wipe a needle with rubbing alcohol to sterilize it.
4. Puncture the blister with the sterilized needle at its edge, making the hole big enough to drain fluid.
5. Let the fluid drain, making sure to leave the overlying skin in place. Note:This skin will help prevent infection.
6. Apply an antibiotic ointment (eg, bacitracin) to the blister, and bandage the affected area.
7. Once the overlying skin has dried, allow it to fall off naturally or use sterilized scissors to cut the dead skin off. Apply antibiotic ointment and a bandage, if necessary.

Blisters usually just need time to heal on their own. Keep a blister clean and dry and cover it with a bandage until it goes away. While it heals, try to avoid putting pressure on the area or rubbing it.

We also offer a free certificate of completion. To receive the certificate you must pass a 50-question test with a score of 70 or higher. Check our Basic First Aid Certificate of Completion page for more information.