Why do I keep getting blood blisters in my mouth?

Finding blood in a blister inside your mouth can be alarming, especially when it keeps happening. Most of the time, it's from biting or rubbing the same spot, but recurring blisters can have other causes too. Since a few different problems can look alike, it's worth having your dental provider take a look. 

What you will learn in this article: 

• Biting, chewing or rubbing may trigger a mouth blood blister. 

• A recurring blister may have several possible causes. 

• Blood thinners can make bleeding or bruising last longer. 

• A blister that keeps returning or does not heal should be checked. 

If blood blisters in your mouth keep coming back, schedule an appointment with an Aspen Dental provider. Your care team can look at the spot and check for a cause that needs attention. 

What is a blood blister in your mouth? 

A mouth blood blister is a raised spot that contains blood beneath the lining of your mouth. It may break and leave a shallow sore. 

One condition that can cause sudden or recurring blood blisters is called angina bullosa hemorrhagica, or ABH. In a study of 23 adults with ABH, researchers found the largest share of blisters on the soft palate, which is the back part of the roof of the mouth. Chewing-related injury was the most common reported trigger, and some patients had repeat episodes. Because the study was small and conducted in Brazil, it cannot tell us what causes every mouth blood blister.¹ 

Why do blood blisters keep coming back? 

A blister that appears once may come from a single injury. If it keeps returning, the same area may be getting bitten or rubbed. A dental provider can check for a local cause and decide whether another type of evaluation is needed. 

Biting or rubbing your cheek 

Your teeth may catch the same part of your cheek when you chew. A sharp or broken tooth can also rub the tissue. If the blister keeps forming in the same spot, your dental provider can check for a rough edge or another source of irritation. 

Braces, dentures and other appliances 

A brace, retainer or denture may rub one area of your mouth. If the same spot keeps getting sore or blistered, ask your dental provider to check the appliance. Do not try to bend, file or adjust it yourself. 

Medicines and blood-clotting problems 

Some medicines affect how your blood clots. The American Dental Association notes that anticoagulant and antiplatelet medicines can cause bleeding that lasts longer or easier bruising. This may matter when tissue inside your mouth is injured, but it does not prove that the medicine caused the blister.² 

Tell your dental provider about every medicine you take, especially blood thinners. Do not stop or change a prescribed blood thinner without talking to the doctor who prescribed it. Most patients on blood thinners don't need to stop them for dental care; your provider has ways to manage bleeding during treatment. 

If you take a blood thinner and need a tooth removed, ask your dental provider about taking blood thinners before the visit. Blood thinners can also affect bleeding during dental cleanings. 

When does a recurring blood blister need a closer look? 

Tell your dental provider or doctor if: 

• The blister keeps returning. 

• Blisters appear in different parts of your mouth. 

• You bruise or bleed easily elsewhere on your body. 

• There is no clear bite, rub or other injury. 

• The area remains sore, numb, raised or thick. 

• The blister breaks and the area does not heal. 

The National Institute of Dental and Craniofacial Research advises getting an examination when an area in the mouth or on the lip stays sore or irritated, forms a lump or becomes thicker and is still present after two weeks.³ 

Get emergency help if a large blister near the back of your mouth makes it hard to breathe or swallow. In rare cases, a large blood blister near the soft palate can block the airway. 

When should you see a dental provider about a blood blister? 

See a dental provider any time a blood blister keeps returning. Tell them about any medicines you take, especially blood thinners. That changes what they check first. A dental provider can look for a sharp tooth edge, a poor-fitting appliance or another cause inside your mouth. If the cause seems tied to a medical condition, your dental provider may send you to your doctor for a closer look. 

Recurring blood blisters do not have to be something you just live with. Contact your local dental provider to have the spot checked and find out what is causing it. 

Why do I keep getting blood blisters in my mouth? FAQs 

Still have questions about recurring blood blisters in your mouth? These answers cover a few common concerns. 

Are recurring blood blisters in the mouth dangerous? 

Some mouth blood blisters are harmless, but you cannot always tell the cause by looking at one. Have a dental provider examine a blister that keeps returning, appears without a clear injury or does not heal. 

Can stress cause blood blisters in your mouth? 

Stress does not prove that it caused the blister. However, you may bite your cheek or lip when you feel stressed. A dental provider can check for signs of repeated injury and tell you whether a mouth guard or another treatment may help. 

How long should a mouth blood blister take to heal? 

Healing time depends on the cause. In the study of 23 adults with ABH, the blisters often opened within minutes or hours and healed over several days. These results apply to ABH and not to every type of mouth blister.¹ Have the area checked if it keeps returning or leaves a sore that remains after two weeks. 

Should I pop a blood blister in my mouth? 

Do not pop it yourself. Opening the blister may cause more injury or bleeding. Let it heal, and have your dental provider examine it if it is large, painful or keeps returning. 

Can a blood blister in the mouth be a sign of a blood disorder? 

A recurring blood blister does not automatically mean you have a blood disorder. However, tell your dental provider or doctor if you also bruise easily, bleed often or take medicine that affects clotting. They can decide whether you need blood tests or another examination. 

Sources 

¹ National Institutes of Health, National Library of Medicine: “Angina bullosa haemorrhagica: A 14-year multi-institutional retrospective study from Brazil and literature review.” https://pubmed.ncbi.nlm.nih.gov/34564682/ 

² American Dental Association, Oral Health Topics: “Oral Anticoagulant and Antiplatelet Medications and Dental Procedures.” https://www.ada.org/resources/ada-library/oral-health-topics/oral-anticoagulant-and-antiplatelet-medications-and-dental-procedures 

³ National Institute of Dental and Craniofacial Research: “Oral Cancer.” https://www.nidcr.nih.gov/sites/default/files/2020-09/oral-cancer.pdf