In this article
Blisters are tiny pockets filled with fluid that form under the skin, typically in response to injury. Most blisters develop below the epidermis, the outermost layer of the skin.
A blood blister forms when you damage blood vessels, and the blister fills with blood instead of clear liquid. Most blood blisters look similar to friction blisters. They are usually black, red, or purple.
Blood blisters are often initially bright red and transition to purple or black. Most people experience:
In many cases, these blisters are visible, and you can usually feel them with your tongue.
Most people develop only one blood blister at a time. Blood blisters can occur anywhere in the mouth, but they tend to develop on soft surfaces like the underside of the lips, tongue, or cheeks.
Blood blisters usually form when you pinch the skin without breaking it. When this occurs, blood leaks from the damaged blood vessel into the space between the skin's outermost layer (epidermis) and second layer (dermis). It pools, forming a blister.
Blood blisters in the mouth may develop in response to biting your tongue or cheek. Aside from injury, they may also occur due to:
Generally, it’s a good idea to talk to a doctor if you develop blood blisters in your mouth. It’s essential to do so if:
Most of the time, there’s no way to get rid of blood blisters in your mouth. They should heal on their own, usually after around a week or two.
A doctor may drain large or painful blood blisters using a needle or cutting the blister open with sterilized tools.
If a blood blister is infected, a doctor will prescribe antibiotics.
If you develop frequent or numerous blood blisters in the mouth, or they occur without cause, a doctor may order tests to rule out an underlying condition.
To manage pain related to blood blisters, apply a covered ice pack to the area for 20 minutes. Repeat this process several times a day or as needed.
If blood blisters are painful, try taking over-the-counter (OTC) pain relievers such as ibuprofen or acetaminophen.
To prevent the risk of infection, gargle a mixture of 1 cup of warm water and 1 tsp of salt. Using antibacterial mouth rinses can also help reduce the risk of infection. Choose mouth rinses that don’t contain alcohol, which can further irritate the blister and dry the skin around it.
Never try to pop a blood blister or force it to drain. Also, never try to peel the skin around the blood blister off.
Avoid alcoholic drinks and spicy, salty, and acidic foods or beverages while the blister heals. Avoiding sharp or hard foods may also reduce the risk of further damaging the blister or surrounding area.
Without treatment, most blood blisters heal or begin to heal after about a week. If a blood blister doesn’t heal on its own or recurs, talk to a doctor.
Unless they are related to an underlying health condition, blood blisters in the mouth should not recur.
Blood blisters in the mouth can look like other types of mouth sores:
Also known as cold sores, fever blisters develop due to infections with the herpes simplex virus. Unlike blood blisters, fever blisters are typically filled with clear fluid, though they can become red and swollen.
Most people also feel a localized tingling, itching, or burning sensation 12 to 24 hours before the blisters emerge. Once they rupture, clear or yellow fluid will leak out.
Also known as mouth ulcers, canker sores are among the most common forms of mouth sores. Most canker sores are red on the outside with a yellow, white, or gray middle. Unlike blood blisters, canker sores tend to be flat.
Oral cancer can cause white or red mouth sores. Unlike blood blisters, oral cancer sores don’t get better or resolve with time.
Lichen planus is a chronic inflammatory condition that can impact the gums, tongue, and inside of the cheeks. People with lichen planus can develop red, swollen sores in their mouth or raised, lacy-looking patches.
There is no way to prevent blood blisters due to an underlying condition. But some tips for preventing blood blisters in the mouth include:
Most of the time, blood blisters in the mouth form because of an injury. Seek medical attention if you develop blood blisters in your mouth.
Talk to a doctor as soon as possible if blood blisters in the mouth don’t heal on their own or are accompanied by other symptoms.
In this article