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A blister is a small bubble on the skin that could be filled with fluid and is usually caused by forceful friction, burning, freezing, chemical exposure, or infection.
Blisters can be a real pain — think of the last time you went on a long hike in the woods or maybe a pleasant stroll on the beach in less-than-ideal sandals. The constant rubbing of exposed skin on your feet can lead to the formation of unseemly blisters. They are not too annoying on their own, but when they pop, they can be quite painful. Of course, blisters can be caused by other conditions, as well. While usually benign, they are sometimes the harbinger of a severe medical condition if they come on severely with no obvious cause.
Your skin is composed of multiple layers which are held together by little proteins. All that a “blister” is, in general, is when these layers become separated from one another. Your body then naturally oozes fluids into this new space between the two layers, creating that classic blister appearance. Over time, this fluid can drain and the layers may reattach, but many blisters tend to pop or be rubbed open before this can occur. When this happens, the underlying layer of skin is exposed to the air and is at a mildly increased risk of infection. What you notice though, is the pain associated with a popped blister, which is due to the exposed nerve endings on this deeper layer of skin.
Common accompanying symptoms of blisters
Blisters may be associated with these common symptoms:
- Pain and irritation
- Skin sloughing
- Skin redness
What causes a blister?
When you hear the word blister, the first thought you usually have is of a blister on your foot after soccer practice or after walking in uncomfortable shoes. While most blisters are simple in nature like those, some serious medical conditions are associated with skin blistering.
Causes of blisters related to skin conditions may include the following.
- Dermatologic conditions: Various dermatologic conditions are associated with blistering of the skin.
- Trauma: Repetitive trauma of the skin, such as what might occur to your heel while walking in your favorite boots for miles, can lead to blistering as the repeated rubbing motion separates the layers of skin.
Environmental causes may be related to certain exposures or lifestyle habits.
- Burns: Exposure to high temperatures causes the skin to blister. Blisters are characteristic of second-degree burns. The same may occur with exposure to extremely cold surfaces.
- Irritants and chemical exposure: Environmental irritants like poison ivy can cause immediate blistering-type allergic reactions which are itchy and uncomfortable. Chemicals may also react with the skin and form blisters.
- Drugs: Severe reactions can occur in response to some drugs, characterized by severe blistering and sloughing of the skin. These are extremely rare.
Various autoimmune diseases can cause blistering of the skin. This blistering can range in severity from extremely mild to severe and deadly.
Metabolic causes can involve how your body processes nutrients.
- Tumors: Rare tumors of the gastrointestinal tract can cause outbreaks of characteristic blisters and rash.
- Nutritional deficiencies: If you do not have sufficient stores of various nutrients it can cause skin blisters and rashes.
Infections with herpes or chickenpox can cause blister formation.
This list does not constitute medical advice and may not accurately represent what you have.
Friction blister on the hand
Friction blisters are very common and occur when fluid accumulates beneath the outer layer of the skin. They’re caused by friction from carrying heavy objects or repetitive use.
Top Symptoms: hand pain, blister on the hand, blister caused by friction, constant skin changes, rash with bumps or blisters
Symptoms that always occur with friction blister on the hand: blister caused by friction, blister on the hand
Shingles is a painful rash that results when the varicella zoster virus (VZV) — the same virus that causes the chickenpox — becomes reactivated. It results in a painful rash of small fluid-filled blisters (vesicles) over a single strip of skin on one side of the body..
Cellulitis is a bacterial infection that can affect the skin of any part of the body. Cellulitis most commonly appears on the legs in adults and on the head in children. It can be the result of any condition that compromises the protective barrier of the ski..
Blistering disease (pemphigus)
Pemphigus is an autoimmune disorder, meaning that the immune system attacks healthy cells in the skin and mouth, causing blisters and sores. This is a rare disease, and doctors are not completely sure of the cause.
Rarity: Ultra rare
Top Symptoms: nasal ulcer, skin peeling, hoarse voice, painful rash, red or pink, rough patch of skin
Urgency: Primary care doctor
Friction blister on the foot
Friction blisters are very common among both men and women of all ages. They most commonly affect the feet due to lifting heavy loads, repetitive overuse, or ill-fitting shoes. The layers of skin become separated from mechanical force, and the body fills the gap with fluid.
Top Symptoms: foot pain, foot blister, blister likely from friction, constant skin changes, foot skin changes
Symptoms that always occur with friction blister on the foot: foot blister, blister likely from friction
Irritant contact dermatitis
Irritant contact dermatitis means a skin reaction that is caused by directly touching an irritating substance, and not by an infectious agent such as a bacteria or virus.
Common causes are soap, bleach, cleaning agents, chemicals, and even water. Almost any substance can cause it with prolonged exposure. Contact dermatitis is not contagious.
Anyone who works with an irritating substance can contract the condition. Mechanics, beauticians, housekeepers, restaurant workers, and health care providers are all susceptible.
Symptoms include skin that feels swollen, stiff, and dry, and becomes cracked and blistered with painful open sores.
A medical provider can give the best advice on how to heal the skin and avoid further irritation. Self-treatment can make the problem worse if the wrong creams or ointments are used.
Diagnosis is made through patient history, to find out what substances the patient comes into contact with, and through physical examination of the damaged skin.
Treatment involves avoiding the irritating substance if possible. Otherwise, the person can use petroleum jelly on the hands underneath cotton and then rubber gloves.
Top Symptoms: rash with well-defined border, itchy rash, red or pink, rough patch of skin, painful rash, red rash
Symptoms that always occur with irritant contact dermatitis: rash with well-defined border
Symptoms that never occur with irritant contact dermatitis: fever, black-colored skin changes, brown-colored skin changes, blue-colored skin changes
Sunburn is an acute condition related to excess exposure to ultraviolet rays. It usually resolves over the course of a few days and acute symptoms can be managed; however, it can have morbid long-term effects if the sunburn is particularly severe. Symptoms include reddening of the skin (erythema), fluid-filled bump..
Partial thickness burn
A burn is called partial-thickness when there is damage to some of the lower layers of skin. This can cause blistering and pain, but is not generally dangerous if treated properly.
Top Symptoms: burn, blistering burn, blanching burn, burn that is painful to touch
Symptoms that always occur with partial thickness burn: burn, blistering burn, burn that is painful to touch, blanching burn
Symptoms that never occur with partial thickness burn: open wound from burn
Urgency: Primary care doctor
Allergic reaction to poison ivy/oak/sumac
Plants of the Toxicodendron genus are found throughout the continental United States, and exposure to these plants is a leading cause of contact dermititis, a medical term used to describe irritation and itching of the skin.
Top Symptoms: rash, itchy rash, red rash, skin changes on arm, stinging or burning rash
Symptoms that always occur with allergic reaction to poison ivy/oak/sumac: itchy rash, rash
Symptoms that never occur with allergic reaction to poison ivy/oak/sumac: fever
Many types of chemicals can cause damage to the skin, including strong acids and bases such as drain cleaner.
Symptoms that never occur with chemical burn: open wound from burn
Urgency: Hospital emergency room
Blister treatments and relief
For the most part, blisters are easily managed at home. Most blisters are caused by just repetitive rubbing of the skin surface, such as the blisters you may get on your heels after a long walk. However, if you are experiencing blisters on a significant portion of your body without a clear cause, have severe burns, blisters after taking medication, or oral blisters, you should consider seeking medical attention.
Various at-home remedies that may be helpful in caring for blisters include the following.
- Coverage: Try not to pop blisters if you have them. Popping blisters exposes the underlying deeper layers of skin and makes them more prone to infection. A loose overlay can help protect the fragile skin. If you do pop the blister, do not remove the overlying skin.
- Prevention: You can prevent blisters from shoes by using products such as Moleskin to protect vulnerable spots on your feet.
- Creams: For blisters caused by exposure to poison ivy and other irritants, anti-itch creams can be helpful to reduce scratching and subsequent infection risk.
- Cool water: For burns specifically, it is helpful to douse the exposed area in cool water directly after exposure to high temperatures.
When to see a doctor
If more conservative methods do not provide relief, you can consult your physician for the following.
- Medication: Conditions that cause widespread blistering are often treatable with various medications. Such medications help dampen the formation of blisters, allowing the skin time to heal.
- Other treatments: Rare causes of blisters such as cancer may be amenable to chemotherapy or surgery.
When it is an emergency
If you experience any of the following, you should seek immediate treatment.
- Severe burns, circumferential burns, or burns of the hands or genitals
- Blisters after taking a medication
- Severe blisters of the mouth
- Severe blisters that become infected
FAQs about blister
Do blisters go away on their own?
The most common type of blister is an abrasion blister, usually brought about by some sort of strenuous rubbing of skin against an object. They can be caused by running in shoes that don't fit, doing a repetitive task like yard work for the first time without gloves, or even working out without proper hand protection. Blisters that come about in this way usually disappear and become less tender naturally with time. Blisters may also arise because of a rash or exposure. Burns from the sun or direct exposure to fire or steam often blister, rashes from exposure to toxins like poison ivy may blister, and chemical burns may also blister. If you have a rash from an unknown source that is blistering you should seek medical attention.
What do you do if you accidentally pop a blister?
There is not much to do aside from keeping the site of the popped blister clean and protected. You may notice a red and tender area under the skin of the blister. For your own comfort and to prevent infection, it can help to place a dry bandage over the popped blister and to change it one to two times per day, keeping it dry before changing it. But, in most cases, it will resolve on its own.
Can diabetes cause blisters on my body?
Yes, diabetes can cause blisters. This is called bullous disease of diabetes. The blisters caused by diabetes are under the skin and do not have a clear cause. They are often red and swollen and most commonly appear on the feet or legs. They commonly and spontaneously resolve over the course of a few weeks.
Can blisters spread to other parts of my body?
Yes, depending on the cause, blisters can spread and often do spread. Blisters caused by a sunburn, for example, will develop first in the area most intensely exposed to the sun. If you have received a sufficiently high dose of UV radiation, you may later develop blisters in other areas as well. Autoimmune disorders of the blood vessels or skin, infectious diseases, and exposure to certain plants and chemicals can all cause blisters to spread from one area of the body to another. Health professionals are trained to look at the distribution of a rash with blisters to determine its cause. If you have a spreading rash with blisters you should see a health professional for diagnosis.
Can blisters get infected?
Yes, blisters can get infected. The chance of infection is higher for larger blisters, but is present for any size of blister. Keys to ensuring that the blister does not get infected, is keeping any substance (e.g. dirt, oil, water, antibacterial gel) from getting caught under the dead skin overlying the blister. This can be done either by carefully removing the skin or by keeping the blister dry and covered during times when it might be exposed to some infectious material.
Questions your doctor may ask about blister
- Any fever today or during the last week?
- What color is the skin change?
- Is your rash raised or rough when you run your hand over the area of skin?
- Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.
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- Blisters. U.S. National Library of Medicine: MedlinePlus. Updated November 15, 2016. MedlinePlus Link
- Blisters. Johns Hopkins Medicine. Johns Hopkins Medicine Link
- How to prevent and treat blisters. American Academy of Dermatology. AAD Link
- The ABCs of blister care. Nationwide Children’s Hospital. Nationwide Children's Hospital Link
- Blisters. NHS. Updated December 12, 2017. NHS Link