Causes

The most common cause of blisters is friction or pressure. Wearing shoes without socks or wearing shoes that are too tight can lead to blisters. You may develop a blister on your palms and fingers if you are doing work that causes rubbing.

Blisters can also be caused by burns, allergic reactions, chemical irritation, or more serious health problems such as shingles or chickenpox. Tiny blisters that appear on the genitals can be herpes simplex virus type 2. Talk with your doctor about any large, unusual blisters that are not caused by friction.

Prevention

To keep common friction blisters from developing, wear work gloves when doing physical labor. To prevent blisters on your feet:

• Use foot powder.
• Wear a thin sock that wicks away moisture under a thick, moisture-absorbing sock.
• Wear shoes that fit properly.
• Hikers should wear good shoes and thin inner socks and change socks at least once a day. Moist feet get more blisters.
• Use moleskin (a soft material that prevents chafing, which you can purchase from a drugstore) on any hot spots that develop to prevent a blister from forming.

Self-Care

• If the blister breaks open, treat it like an open wound. Wash it with soap and warm water. Apply an antibacterial ointment and cover it with a clean bandage. Watch for signs of infection, such as redness, pain, swelling, or red streaks leading toward the heart.
• Friction blisters are best left unbroken if skin irritation can be avoided until the fluid disappears.