Group Health
RETURN

Blisters are fluid-filled bumps that look like bubbles on the skin. You may develop a blister on your foot when you wear new shoes that rub against your skin or on your hand when you work in the garden without wearing gloves. Home treatment is often all that is needed for this type of blister.

Other types of injuries to the skin that may cause a blister include:

  • Burns from exposure to heat, electricity, chemicals, radiation from the sun, or friction.
  • Cold injuries from being exposed to cold or freezing temperatures.
  • Some spider bites, such as a bite from a brown recluse spider . Symptoms of a brown recluse spider bite include reddened skin followed by a blister that forms at the bite site, pain and itching, and an open sore with a breakdown of tissue (necrosis) that develops within a few hours to 3 to 4 days following the bite. This sore may take months to heal.
  • Pinching the skin forcefully, like when a finger gets caught in a drawer. A blood blister may form if tiny blood vessels are damaged.

Infection can cause either a single blister or clusters of blisters.

  • Chickenpox (varicella) is a common contagious illness that is caused by a type of herpes virus. Chickenpox blisters begin as red bumps that turn into blisters and then scab over. It is most contagious from 2 to 3 days before a rash develops until all the blisters have crusted over.
  • Shingles , often seen in older adults, is caused by the same virus that causes chickenpox. Shingles blisters look like chickenpox, but they usually develop in a band on one side of the body.
  • Hand-foot-and-mouth disease, another type of viral infection, most often occurs in young children. Symptoms include a rash of small sores or blisters that usually appear on the hands and feet and in the mouth.
  • Cold sores , sometimes called fever blisters, are clusters of small blisters on the lip and outer edge of the mouth. They are caused by the herpes simplex virus. Cold sore-type blisters that develop in the genital area may be caused by a genital herpes infection.
  • Impetigo is a bacterial skin infection. Its blisters, which often occur on the face, burst and become crusty (honey-colored crusts).
  • Infected hair follicles (folliculitis ) cause red, tender areas that turn into blisters at or near the base of strands of hair.
  • A scabies infection, which occurs when mites burrow into the skin, may cause tiny, itchy blisters that often occur in a thin line or curved track.
  • Bedbugs can cause tiny, itchy blisters anywhere on the body.

Inflammation may cause skin blisters.

  • Contact dermatitis occurs when skin touches something in the environment that causes an allergic reaction.
  • Blisters may develop from a disease that causes your body to attack your own skin (autoimmune disease).

Occasionally a prescription or nonprescription medicine or ointment can cause blisters. The blisters may be small or large and usually occur with reddened, itchy skin. If the blisters are not severe and you do not have other symptoms, stopping the use of the medicine or ointment may be all that is needed. Blisters may also occur as a symptom of a toxic reaction to a medicine. This reaction is called Stevens-Johnson syndrome. Blisters that occur with other signs of illness, such as a fever or chills, may mean a more serious problem.

Check your symptoms to decide if and when you should see a doctor.

Most blisters heal on their own. Home treatment may help decrease pain, prevent infection, and help heal large or broken blisters.

  • A small, unbroken blister about the size of a pea, even a blood blister, will usually heal on its own. Use a loose bandage to protect it. Avoid the activity that caused the blister.
  • If a small blister is on a weight-bearing area like the bottom of the foot, protect it with a doughnut-shaped moleskin pad . Leave the area over the blister open.
  • If a blister is large and painful, it may be best to drain it. Here is a safe method:
    • Wipe a needle or straight pin with rubbing alcohol.
    • Gently puncture the edge of the blister.
    • Press the fluid in the blister toward the hole so it can drain out.
  • Do not drain a blister of any size if:
    • You have a condition such as diabetes, HIV, cancer, or heart disease, because of the risk of infection.
    • You think your blister is from a contagious disease, such as chickenpox, because the virus can be spread to another person.
  • If a blister has torn open, or after you have drained a blister:
    • Wash the area with soap and water. Do not use alcohol, iodine, or any other cleanser.
    • Don't remove the flap of skin over a blister unless it's very dirty or torn or there is pus under it. Gently smooth the flap over the tender skin.
    • Apply an antibiotic ointment and a clean bandage. If the skin under the bandage begins to itch or a rash develops, stop using the ointment. The ointment may be causing a skin reaction.
    • Change the bandage once a day or anytime it gets wet or dirty. Remove it at night to let the area dry.

Watch for a skin infection while your blister is healing. Signs of infection include:

  • Increased pain, swelling, redness, or warmth around the blister.
  • Red streaks extending away from the blister.
  • Drainage of pus from the blister.
  • Fever.

Home remedies may relieve itching from blisters. One way to help decrease itching is to keep the itchy area cool and wet. Apply a cloth that has been soaked in ice water, or get in a cool tub or shower.

Medicine you can buy without a prescription
Try a nonprescription medicine to help treat your fever or pain:
  • Acetaminophen, such as Tylenol
  • Nonsteroidal anti-inflammatory drugs (NSAIDs):
    • Ibuprofen, such as Advil or Motrin
    • Naproxen, such as Aleve or Naprosyn
  • Aspirin (also a nonsteroidal anti-inflammatory drug), such as Bayer or Bufferin

Talk to your child's doctor before switching back and forth between doses of acetaminophen and ibuprofen. When you switch between two medicines, there is a chance your child will get too much medicine.

Safety tips
Be sure to follow these safety tips when you use a nonprescription medicine:
  • Carefully read and follow all directions on the medicine bottle and box.
  • Do not take more than the recommended dose.
  • Do not take a medicine if you have had an allergic reaction to it in the past.
  • If you have been told to avoid a medicine, call your doctor before you take it.
  • If you are or could be pregnant, do not take any medicine other than acetaminophen unless your doctor has told you to.
  • Do not give aspirin to anyone younger than age 20 unless your doctor tells you to.

Symptoms to watch for during home treatment

Call your doctor if any of the following occur during home treatment:

  • A skin infection develops.
  • A crusty blister that drains honey-colored fluid develops.
  • Signs of illness develop, such as shaking chills, fever, belly pain, vomiting or diarrhea, muscle or joint aches, headache, or a vague sense of illness.
  • Symptoms do not improve, or they become more severe or frequent.

Some of the most common types of blisters can be prevented.

  • To prevent blisters caused by rubbing (friction blisters):
    • Avoid wearing shoes that are too tight or that rub your feet. Roomy footwear has a wide toe box with more room for your toes and the ball of your foot. You should be able to wiggle your toes in your shoes. Foot size may vary half a size from the morning to the evening or after a day at work, so purchase shoes at the end of the day when your feet are most swollen.
    • Wear gloves to protect your hands when you are doing heavy chores or yard work.
  • Avoid contact with any plants or other substances that are known to cause blistery rashes. For more information, see the topic Poison Ivy, Oak, or Sumac.
  • Avoid contact with people who have infections that are known to cause blisters, such as:
    • Viral illnesses, including chickenpox, shingles, genital herpes infection, and cold sores.
    • Bacterial skin infection (impetigo).
    • Scabies mite infection.

To prepare for your appointment, see the topic Making the Most of Your Appointment.

You can help your doctor diagnose and treat your condition by being prepared to answer the following questions:

  • When did your blisters start?
    • Did your blisters begin after an injury, such as a burn or cold injury or an insect or spider bite?
    • Were you around someone who had similar blisters before your blisters appeared? If so, what type of contact did you have with that person?
    • Did you come in contact with something in the environment, such as poison ivy, oak, or sumac, before the blisters appeared?
    • Did any chemicals come in contact with your skin? Chemicals include soap, laundry detergent, lotion, cosmetics, or nonprescription medicines.
  • Have you had these blisters before? If so, were they diagnosed by your doctor? Did you have any treatment?
  • Do your blisters itch or hurt?
  • What prescription or nonprescription medicines are you taking? Are you using any ointments or salves?
  • Do you feel sick? If so, in what way? Do you have a fever?
  • Have you recently traveled outside your country or to a rural area or farm?
  • In which sports activities are you involved? How often?
  • What home treatment have you tried? Did it help?
  • Do you have any health risks?

By: Healthwise Staff Last Revised: December 10, 2012
Medical Review: William H. Blahd, Jr., MD, FACEP - Emergency Medicine
H. Michael O'Connor, MD - Emergency Medicine

© 1995-2013 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.
Click here to learn about Healthwise