Blood Blister in Mouth: Causes, Treatment, Symptoms

What are Blood Blisters?

Blisters occur when the upper layer of skin is injured. As fluid from within injured tissue pools between layers of your skin, the body forms a blister to protect the damaged area, which is, in turn, filled with this fluid.

Most blisters will appear as clear fluid-filled sacs, but if the blood vessels beneath the injury site are also damaged, a blister can fill with blood and turn red or purple. While you will more commonly see blood blisters on your hands or feet, it is possible to form blood blisters in the mouth.

Causes of Blood Blisters in the Mouth

There are several reasons why blood blisters may form in the mouth, with some being more common than others. The conditions and actions that can cause them include:

• Soft tissue trauma (friction, cuts, etc.)
• Allergic reactions
• Vitamin deficiencies
• Viral infections (such as oral herpes, which can cause lesions that may bleed or be mistaken for blood blisters)
• Diabetes
• Angina bullosa hemorrhagica
• Low platelet count (Thrombocytopenia)

Angina Bullosa Hemorrhagica

One of the lesser-known causes of blood blisters in the mouth is angina bullosa hemorrhagica (ABH), a rare condition most common in those over 40.

ABH causes blood blisters to occur within the mouth, typically on or under the tongue or on your gums. These blisters are usually painful and last only a short time before bursting and leaving a shallow ulcer, which should heal without scarring. Some blisters caused by angina bullosa hemorrhagica last for as little as a couple of minutes before bursting.

Most blisters caused by ABH are not serious, but as they can be painful and potentially disruptive, it is best to speak to a doctor if you believe you are suffering from the condition.

Causes of ABH

Though the exact cause of angina bullosa hemorrhagica is not yet known, trauma is the most commonly cited precipitating factor. Over half the reported cases of ABH occur after minor traumas, including:

• Burns from hot food
• Trauma sustained after restorative dental treatments
• Trauma sustained from the treatment of gum disease

Unfortunately, ABH will not always have a distinct cause. You should contact your doctor if you believe you are suffering from angina bullosa hemorrhagica.

Tissue Trauma

Most blood blisters in the mouth will form following small traumas, including biting the tongue or cheek accidentally and when reacting to dental injections.

Sharp teeth and broken fillings are also capable of causing small traumas within the mouth and, in turn, blisters.

Tissue Burn

Another especially common blood blister in the mouth is burns. Commonly occurring after biting into hot food or sipping on a scalding drink, mouth burns can lead to painful and blistered sores that include blood blisters in the mouth.

If you burn your mouth, take care to keep it as clean as possible, as this can speed up the healing process and reduce the risk of infection. Use saltwater or antimicrobial rinses and try to limit smoking.

Tissue Irritation

Mouth tissue can become irritated for several reasons. Friction, often caused by braces, is a common cause of sores and blood blisters in the mouth as damaged tissue blisters over to protect itself and heal.

Irritation within the mouth also stems from habits, including biting your fingernails, chewing on pens or straws, and chewing tobacco. These habits can not only lead to blood blisters and sores but also worsen existing sores in the mouth.

Thrombocytopenia

Thrombocytopenia is the scientific name given to a low platelet count. Your platelets are blood cells that help blood clot.

Platelet count can drop for several reasons, with the most common thrombocytopenia causes including:

• Pregnancy
• Anemia
• Viral infections (including HIV and Hepatitis C)
• Medication side effects
• Cancer

A low platelet count makes it difficult for blood to clot. This means even a minor injury or friction inside the mouth can cause prolonged bleeding under the skin, leading to the formation of a blood-filled blister where one might not normally form.

Allergies

Allergies can cause irritation and trauma within the mouth which leads to blood blisters. Some allergies are more likely to cause blood blisters in the mouth than others; these include allergies to:

• Highly acidic foods (citrus fruits, etc.)
• Cinnamon
• Astringents (chemicals that constrict body tissues, often used in toothpaste)

Symptoms of Blood Blisters in the Mouth

A blood blister in the mouth will look and feel like blisters on any other part of the body. Most blood blisters in the mouth will be big enough to be easily visible, but their dark red or purple coloring can make them blend in with the inside of the mouth and be harder to spot.

If you are unsure as to whether you have a blood blister in the mouth, the most common symptoms of the condition include:

• Mild to severe pain around the blister site
• Difficulty and pain when cleaning your teeth
• An itch inside the mouth
• Pain when eating salty, spicy, or acidic foods

Blood Blisters Vs. Other Mouth Sores

Differentiating between mouth sores can be hard, especially when their appearances are similar. If you have a sore in the mouth and are wondering how to identify it, recognising the following differences may help.

Canker Sores

Canker sores are small red or white ulcers that form within the mouth, typically on the tongue or inside of the lips.

While a canker sore on the tongue or lip will be covered in a white or yellow film, a blood blister in the mouth will typically be larger and much darker in color. Both sores can be painful.

Fever Blisters

Fever blisters can look similar to blood blisters, so to distinguish the two, it is important to know the accompanying symptoms.

A fever blister, as the name suggests, can accompany a fever and may also appear with swollen lymph nodes. Before fever blisters form, you may feel a tingling sensation, unlike blood blisters in the mouth, which form suddenly and without warning. Fever blisters may also appear on the outer lips and under the nose, not just in the mouth.

Are Blood Blisters Contagious?

If you are experiencing them for the first time, it is natural to wonder, 'Are blood blisters in the mouth contagious?'

Whether or not your blood blister is contagious will depend on whether its underlying cause is communicable or not. If the blood blister in the mouth is due to trauma, a vitamin deficiency, diabetes, allergic reactions, or other non-transmissible diseases, then the condition will not be contagious.

On the other hand, if the sore in your mouth is caused by a transmissible virus like oral herpes (cold sores), the virus itself can be contagious through direct contact with the sore. Conditions like HIV or syphilis can have oral symptoms, but they are not a typical cause of blood blisters and have different transmission routes. If you are worried about the underlying cause of your blood blister in the mouth, contact your doctor.

Treatment for Blood Blisters in the Mouth

Although they can be painful, most blood blisters in the mouth will pass on their own and will not require any treatment. For simple at-home blood blister in the mouth treatment, aimed at reducing pain, you may try:

• OTC pain medication.
• Avoiding spicy, salty, or acidic foods.
• Leaving the blister alone and not attempting to burst it.
• Gently swirling coconut oil in your mouth, a practice known as oil pulling, which some find soothing for oral irritations.
• Drinking chamomile tea as it can ease irritation.

In some cases, you may need to visit a doctor for blood blister in the mouth treatment. Visit your doctor if:

• Blood blisters recur regularly
• The blister takes more than 2 weeks to fully heal
• The blister is making swallowing or breathing difficult
• You are experiencing severe pain
• The blister is infected (look for warmth, pus, and swelling)

Gentle Clean, Strong Protection with Oral-B

In most cases, blood blisters in the mouth will be harmless, but if blisters persist and cause severe pain, you should seek medical attention.

While living with blood blisters in the mouth, proper oral care becomes vital both for managing infection and assisting the healing process. For care that treats the mouth gently, with effective cleaning, trust Oral-B.

The Oral-B iO Series is designed to deliver a deep yet gentle clean with every use. Powered by advanced iO™ technology, the iO Series effectively removes plaque while being kind to sensitive areas of the mouth—making it ideal for those managing delicate conditions. Explore the Oral-B iO Series here.