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.
- 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 , which 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. Contact with certain plants, such as poison ivy, oak, and sumac, may occur indirectly.
- 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 that occur with other signs of illness, such as a fever or chills, may indicate a more serious problem.
Use the Check Your Symptoms section to decide if and when you should see a doctor.
A small, unbroken blister [less than 1 in. (2.5 cm) across], even a blood blister, will usually heal on its own.
- Do not try to break the blister. Just leave it alone.
- Leave the blister uncovered unless something rubs against
it. If you do cover it:
- Apply a loose bandage. Secure the bandage so the tape does not touch the blister. Do not wrap tape completely around a hand, arm, foot, or leg because it could cut off the blood supply if the limb swells. If the tape is too tight, you may develop symptoms below the level of the tape, such as numbness, tingling, pain, or cool and pale or swollen skin.
- If the blister is in an area where pressure is applied, such as on the bottom of your foot, protect it with a doughnut-shaped moleskin pad. Leave the area over the blister open.
- Do not wear the shoes or do the activity that caused a friction blister until the blister heals.
Home treatment may help decrease pain, prevent infection, and help heal large or broken blisters.
- Wash your hands with soap and water before touching blisters. Blisters can easily become infected.
- Most large blisters will break on their own and then heal. If you have a large blister, you may want to drain it depending on where it is. Clean a needle with rubbing alcohol or soap and water, then use it to gently puncture the edge of the blister. Press the fluid in the blister toward the hole you made. Wash the blister after you have drained it, and pat it dry with clean gauze.
- Do not remove the flap of skin covering the blister unless it tears or gets dirty or pus forms under it. If the blister has just a small puncture or break, leave the flap of skin on and gently smooth it flat over the tender skin underneath.
- Apply an antibiotic ointment, such as polymixin B or bacitracin, if you are not allergic to it. The ointment will prevent the bandage from sticking to the blister and may help prevent infection. Do not use alcohol or iodine on the blister because these may delay healing. Do not use an ointment if you know you are allergic to it.
- Loosely apply a bandage or gauze. Secure the bandage so the tape does not touch the blister. Do not wrap tape completely around a hand, arm, foot, or leg because it could cut off the blood supply if the limb swells. If the tape is too tight, you may develop numbness, tingling, pain, or cool and pale or swollen skin below the level of the tape.
- If the skin under the bandage begins to itch or develops a rash, stop using the antibiotic ointment.
- Change the bandage every day and any time it gets wet or dirty. You can soak the bandage in cool water just before removing it to make it less painful to take off.
- Avoid wearing the shoes or doing the activity that caused the blister until the blister heals.
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.
- Swollen lymph nodes in your neck, armpit, or groin.
Home remedies may relieve itching from blisters. One way to help decrease itching is to keep the itchy area cool and wet. Apply a washcloth that has been soaked in ice water, or get in a cool tub or shower.
|Try a nonprescription medicine to help treat your fever or pain:|
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.
|Be sure to follow these safety tips when you use a nonprescription medicine:|
Symptoms to Watch For During Home Treatment
Use the Check Your Symptoms section to evaluate your symptoms 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, abdominal pain, vomiting or diarrhea, muscle or joint aches, headache, or a vague sense of illness.
- Symptoms do not improve or become more severe or frequent.
Some of the most common types of blisters can be prevented.
- To prevent blisters caused by rubbing (friction
- 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:
Preparing For Your Appointment
To prepare for your appointment, see the topic Making the Most of Your Appointment.
You can help your health professional 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?
|Author||Jan Nissl, RN, BS|
|Editor||Susan Van Houten, RN, BSN, MBA|
|Associate Editor||Tracy Landauer|
|Primary Medical Reviewer||Kathleen Romito, MD - Family Medicine|
|Primary Medical Reviewer||William H. Blahd, Jr., MD, FACEP - Emergency Medicine|
|Specialist Medical Reviewer||Alexander H. Murray, MD, FRCPC - Dermatology|
|Specialist Medical Reviewer||Martin Gabica, MD - Family Medicine|
|Last Updated||May 6, 2009|
Last Updated: May 6, 2009