Content Map Terms
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-coloured 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 non-prescription 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.
Check Your Symptoms
The medical assessment of symptoms is based on the body parts you have.
- If you are transgender or non-binary, choose the sex that matches the body parts (such as ovaries, testes, prostate, breasts, penis, or vagina) you now have in the area where you are having symptoms.
- If your symptoms aren’t related to those organs, you can choose the gender you identify with.
- If you have some organs of both sexes, you may need to go through this triage tool twice (once as "male" and once as "female"). This will make sure that the tool asks the right questions for you.
Many things can affect how your body responds to a symptom and what kind of care you may need. These include:
- Your age. Babies and older adults tend to get sicker quicker.
- Your overall health. If you have a condition such as diabetes, HIV, cancer, or heart disease, you may need to pay closer attention to certain symptoms and seek care sooner.
- Medicines you take. Certain medicines, such as blood thinners (anticoagulants), medicines that suppress the immune system like steroids or chemotherapy, or natural health products can cause symptoms or make them worse.
- Recent health events, such as surgery or injury. These kinds of events can cause symptoms afterwards or make them more serious.
- Your health habits and lifestyle, such as eating and exercise habits, smoking, alcohol or drug use, sexual history, and travel.
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 symptoms.
- 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.
Symptoms of infection may include:
- Increased pain, swelling, warmth, or redness in or around the area.
- Red streaks leading from the area.
- Pus draining from the area.
- A fever.
Symptoms of serious illness may include:
- A severe headache.
- A stiff neck.
- Mental changes, such as feeling confused or much less alert.
- Extreme fatigue (to the point where it's hard for you to function).
- Shaking chills.
Symptoms of serious illness in a baby may include the following:
- The baby is limp and floppy like a rag doll.
- The baby doesn't respond at all to being held, touched, or talked to.
- The baby is hard to wake up.
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 deep or 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 years.
- You don't know when your last shot was.
- You have not received 3 doses of the tetanus vaccine series.
- For a clean wound, you may need a shot if:
- You have not had a tetanus shot in the past 10 years.
- You don't know when your last shot was.
- You have not received 3 doses of the tetanus vaccine series.
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 there.
- Mild pain (1 to 4): You notice the pain, but it is not bad enough to disrupt your sleep or activities.
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 grimace.
- 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.
Many prescription and non-prescription medicines, including some that you put directly on the skin, may cause blisters. A few examples are:
- Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (for example, Advil or Motrin).
- Medicines you put on your skin (topical medicines), such as Neosporin or benzocaine (for example, Anbesol, Hurricaine, or Orajel), and ethylenediamine, which is used in some topical medicines.
- Seizure medicines.
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, and HIV/AIDS.
- Long-term alcohol and drug problems.
- Steroid medicines, which may be used to treat a variety of conditions.
- Chemotherapy and radiation therapy for cancer.
- Other medicines used to treat autoimmune disease.
- Medicines taken after organ transplant.
- Not having a spleen.
Seek Care Today
Based on your answers, you may need care soon. The problem probably will not get better without medical care.
- Call your doctor today to discuss the symptoms and arrange for care.
- If you cannot reach your doctor or you don't have one, seek care today.
- If it is evening, watch the symptoms and seek care in the morning.
- If the symptoms get worse, seek care sooner.
Call 911 Now
Based on your answers, you need emergency care.
Call 911 or other emergency services now.
Sometimes people don't want to call 911. They may think that their symptoms aren't serious or that they can just get someone else to drive them. But based on your answers, the safest and quickest way for you to get the care you need is to call 911 for medical transport to the hospital.
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 ambulance unless:
- 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.
Make an Appointment
Based on your answers, the problem may not improve without medical care.
- Make an appointment to see your doctor in the next 1 to 2 weeks.
- If appropriate, try home treatment while you are waiting for the appointment.
- If symptoms get worse or you have any concerns, call your doctor. 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.
- It's best not to drain a blister at home. But when blisters are painful, some people do drain them. If you do decide to drain a blister, make sure to follow these steps.
- Wipe a needle 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:
- Gently wash the area with clean water. Don't use hydrogen peroxide or alcohol, which can slow healing.
- 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.
- You may cover the blister with a thin layer of petroleum jelly, such as Vaseline, and a non-stick bandage.
- Apply more petroleum jelly and replace the bandage as needed.
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.
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.
Try a non-prescription 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 non-prescription medicine:
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-coloured 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:
Preparing For Your Appointment
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 non-prescription 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 non-prescription 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 travelled 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?
Current as of:
July 1, 2021
Author: Healthwise Staff
William H. Blahd Jr. MD, FACEP - Emergency Medicine
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
H. Michael O'Connor MD - Emergency Medicine
Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.