What are Blood Blisters? | Causes | Areas of Skin | Symptoms | Treatment | Medical Attention Required? | Prevention
Blood blisters are a medical condition where fluid-filled bubbles grow out of blood vessels in the skin.
They form under the skin and can be caused by anything from a small cut to an allergic reaction.
Most blood blisters develop when there is too much pressure on blood vessels in the body.
If you find yourself with a blood blister, it’s important to know what to do and not do so your blister gets better quickly.
Keep reading to learn the do’s and don’ts for blood blisters.
What are blood blisters?
Blood blisters occur when there is damage done to blood vessels in the area. This blood starts to leak out and is trapped under the skin as a blood blister.
Blood blisters are caused by trauma to the area. They typically form when blood vessels are broken in the subdermal tissue.
There are also blood vessels in the area that supply blood to your nails.
When trauma occurs, these blood vessels can break and leak blood into this space. If blood vessels are broken, blood can pool in this space rather than be reabsorbed into the body.
For these reasons, blood blisters are one of the more common causes of blood under a toenail or fingernail.
What causes blood blisters?
Blood blisters are caused by blood pooling in a blood vessel, causing the blood to break through the wall of the blood vessel.
Blood blisters can occur on any area that blood vessels are present, but blood blisters can form easily on areas that have been traumatized.
Common causes of blood blisters include blood vessel damage caused by blood thinners, trauma to the area causing blood vessels to break open, and excessive blood flow into an area.
Blood blisters can be a skin reaction caused by a cut, scrape, or burn. It is important to know that blood blisters aren’t always caused by trauma.
Other things that blood blisters can be caused by are insect bites, poison ivy, or heat rash.
Blood blisters most commonly occur when blood vessels are ruptured due to friction or pressure.
People who participate in activities that involve repetitive rubbing causing friction blisters, such as long-distance runners, gymnasts, and weightlifters are very likely to develop blood blisters.
Simple trauma like a blister caused by a shoe, slamming your hand in a door jamb, or hitting your fingers with a hammer while trying to nail something are good examples of reasons people develop blood blisters.
What areas are most likely to be affected by blood blisters?
Blood blisters are a common occurrence that can be painful and uncomfortable if not dealt with properly. The most common sites blood blisters occur are the fingers, hands, and toes.
Other common areas that blood blisters can form are the arms, legs, and trunk of the body.
Blood blisters can form on areas with high blood flow such as fingertips because they lack the protective covering that other parts of the body have.
They usually appear in places where blood flow is high or blood vessels are close to surface levels such as your hands or feet.
What are the symptoms of blood blisters?
The most common symptoms of blood blisters besides the fluid-filled blister are as follows:
- Sharp, stinging pain
- Throbbing sensations
- Soreness
- Redness
- Swelling and Inflammation
They usually take about four to seven days to heal after forming.
How should I treat a blood blister?
Blood blisters can be painful and they can be very itchy. They sometimes burst on their own after a few days if left untreated.
There are several treatments you can do for your blood blister.
If you have a burst blister, you can use a topical antibiotic ointment for the treatment of the blood blister. You should not pop a blood blister on your own as blood blisters can leave behind a scar.
The blood inside of blood blisters is thick and sticky, making it difficult to remove.
If you try to pop blood blisters on your own, you could end up with blood seeping out of the blood blister and possibly getting it dirty and running the risk of infection.
To properly treat blood blisters, you should leave them alone to heal on their own. If a blood blister pops on its own, you should clean the blood blister with soap and water.
Then, use a topical antibiotic ointment to help them heal.

Should I see a doctor if blood blisters develop?
If you develop larger blisters or if blood blisters do not heal within seven days, you should see a doctor. They can also be a painful blister and make it difficult to perform daily activities, such as walking or moving your hands.
You should seek medical help if blood blisters are accompanied by a fever, chills, cough, or shortness of breath. This means it could be an infected blister with bacteria and you should seek medical attention immediately.
If blood blisters are not healed and you begin to notice red streaks near the blood blister, it could be symptoms of infection. You should see a doctor if blood blisters are accompanied by any of these symptoms.
It is very important to deal with blood blisters as soon as possible because they will continue to grow until you do something about them.
How can I prevent blood blisters?
To prevent blood blisters, you can wear protective equipment during activities that lead to blood blisters. For example, if you run and often develop blisters, make sure you have comfortable running shoes and wear thick socks.
It also helps if you have sweaty feet that you keep them as dry as possible when you exercise or perform manual labor.
You should also avoid repetitive movements and stress on the skin as this can cause blood vessels to break and lead to blood blister formation.
Summary
Blood blisters are a type of blister that forms in the subdermal layers of skin and create a pocket of fluid or blood.
They are most often caused by repetitive movements that rub your skin, like your shoes when running, or from trauma, like slamming your hand in a door.
The blood vessels under your skin then break and pool in a layer of skin where there is a blister. Areas that have blood vessels close to the skin are the most likely to be affected, especially your hands and feet.
If you get a blood blister, do NOT pop it as this can lead to scarring and infection. Just let the blister heal on its own and it should be gone within a few days to a week.
Should the blister pop on its own, wash the wound with soap and water and use an antibiotic cream when covering it with a bandage.
You normally do not have to see a doctor with a blood blister. However, if you notice lines emanating from it or have a cough, fever, chills, and shortness of breath then please see a doctor immediately as these could be signs of infection.
To prevent blood blisters, we recommend that you wear protective clothing during activities that are likely to cause them.
This includes wearing thick, comfortable socks and not wearing ill-fitting shoes while running or using gloves while weightlifting.
Should you have any more questions about blood blisters, please consult your pharmacist or medical provider.
References, Studies and Sources
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