Blisters: What You Should Know

Medically Reviewed by Debra Jaliman, MD on September 22, 2021

Whether your shoes are too tight or you touched a hot stove, the result is all too familiar: a painful pocket of skin that's filled with fluid. A single blister like that is usually easy to treat at home, but if you see signs of infection, it's time to call your doctor.

What Causes Blisters?

Friction. You can get blisters when something rubs against your skin, like a tool handle or a new pair of shoes. Unlike corns and calluses, which show up after rubbing that's gone on for a long time, friction blisters come from brief, intense contact on a small area.

Burns. You can get a blister from getting too close to a flame or steam, or if you touch a hot surface. A severe sunburn can also cause blisters.

Cold. An extremely low temperature on your skin can cause blisters. For example, you might get one if your doctor freezes off a wart.

Irritants or allergy triggers. Your skin may blister if you come in contact with certain chemicals, cosmetics, and many plant allergens. You may hear your doctor call this problem irritant or allergic contact dermatitis.

Drug reactions. Sometimes your blisters may be a reaction to a drug you take. When your doctor prescribes a new medicine, always let them know about any drug reactions you've had in the past. And call your doctor if you get a blister after taking a medication.

Autoimmune diseases. Three diseases that curb your immune system -- your body's defense against germs -- can cause blisters:

  • Pemphigus vulgaris, a possibly life-threatening skin disease, causes painful blisters in the mouth or skin. They become raw and crusted over after they burst.
  • Bullous pemphigoid causes less severe blisters that heal faster and are not life-threatening. It mostly happens in elderly people.
  • Dermatitis herpetiformis causes small, itchy blisters. It's a long-term condition that usually starts when you're a young adult. It's linked to gluten sensitivity.

Infection. Blisters are a common symptom of conditions like chickenpox, cold sores, shingles, and a skin infection called impetigo.

Genes.There are rare genetic diseases that cause the skin to be fragile and to blister.

How to Treat Your Blisters

If you leave your blister alone, it often gets better in 1 or 2 weeks. While it's healing, stay away from the activity that brought on the blister.

Some steps you can take to help the healing process:

Put on a loose bandage. It protects your blister while it heals.

Keep it padded. If your blister rubs up against your shoe, you can stop it from getting worse by using padding underneath the bandage.

Usually, there's no need to drain your blister, but you may want to if it's large and hurts a lot. If you decide to do it, use a small needle that you've sterilized with rubbing alcohol. Then pierce the edge of the blister. Afterward, wash the spot with soap and water and cover with petroleum jelly.

When to Call Your Doctor

Be on the lookout for signs that your blister is infected. Call your doctor if it gets more painful or you notice:

  • Pus leaking out
  • Swelling
  • Redness

Show Sources


American Academy of Family Physicians.


American Academy of Dermatology: "How to prevent and treat blisters."

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