Discusses causes of blisters, including injury and infection. Offers symptom checklist to help you decide when to call a doctor. Offers home treatment and prevention tips.
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
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
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
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.
is a bacterial skin infection. Its blisters, which often occur on the face,
burst and become crusty (honey-colored crusts).
follicles (folliculitis) cause red, tender areas that turn into
blisters at or near the base of strands of hair.
scabies infection, which occurs when mites burrow into
the skin, may cause tiny, itchy blisters that often occur in a thin line or
Bedbugs can cause tiny, itchy blisters anywhere
on the body.
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
Stevens-Johnson syndrome. Blisters that occur with
other signs of illness, such as a fever or chills, may
mean a more serious problem.
Mental changes, such as feeling confused or much less
Extreme fatigue (to the point where it's hard for you to
Symptoms of infection may
Increased pain, swelling, warmth, or redness in or
around the area.
Red streaks leading from the area.
Pus draining from the area.
Burns and Electric Shock
Seek Care Now
Based on your answers, you may need care right away. The problem is likely to get worse without medical care.
Call your doctor now to discuss the symptoms and
arrange for care.
If you cannot reach your doctor or you don't have
one, seek care in the next hour.
You do not need to call an
You cannot travel safely either by driving
yourself or by having someone else drive you.
You are in an area
where heavy traffic or other problems may slow you down.
Certain health conditions and medicines weaken the immune system's ability to fight off infection and
illness. Some examples in adults are:
Diseases such as diabetes, cancer, heart disease,
Long-term alcohol and drug
Steroid medicines, which may be used to treat a variety
Chemotherapy and radiation therapy for
Other medicines used to treat autoimmune
Medicines taken after organ transplant.
having a spleen.
Call 911 Now
Based on your answers, you need
Call911or other emergency services now.
You may need a tetanus shot depending
on how dirty the wound is and how long it has been since your last shot.
For a dirty wound that has
things like dirt, saliva, or feces in it, you may need a shot if:
You haven't had a tetanus shot in the past 5
You don't know when your last shot was.
For a clean wound, you may
need a shot if:
You have not had a tetanus shot in the past 10
You don't know when your last shot was.
Pain in children under 3 years
It can be hard to tell how much pain a baby or toddler is in.
Severe pain (8 to 10): The
pain is so bad that the baby cannot sleep, cannot get comfortable, and cries
constantly no matter what you do. The baby may kick, make fists, or
Moderate pain (5 to 7): The baby is
very fussy, clings to you a lot, and may have trouble sleeping but responds
when you try to comfort him or her.
Mild pain (1 to 4): The baby is a little fussy and clings to you a little but responds
when you try to comfort him or her.
Pain in adults and older children
Severe pain (8 to 10): The pain
is so bad that you can't stand it for more than a few hours, can't sleep, and
can't do anything else except focus on the pain.
Moderate pain (5 to 7): The pain is bad enough to disrupt your
normal activities and your sleep, but you can tolerate it for hours or days.
Moderate can also mean pain that comes and goes even if it's severe when it's
Mild pain (1 to 4): You notice the pain,
but it is not bad enough to disrupt your sleep or activities.
Try Home Treatment
You have answered all the questions. Based on your answers, you may be
able to take care of this problem at home.
Try home treatment to relieve the
Call your doctor if symptoms get worse or you have any
concerns (for example, if symptoms are not getting better as you would expect).
You may need care sooner.
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
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
Drainage of pus from the blister.
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:
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.
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.
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
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
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.
with people who have infections that are known to cause blisters, such as:
How this information was developed to help you make better health decisions.