Question: What medical condition causes blood blisters to occur in the mouth, on the tongue, and on the inside of the cheeks?
Answer: Countless conditions can cause blood blisters. To find out which one is the culprit, you need to pay attention to how severe the blisters are, and how often they come and go. You may also need a diagnosis from your doctor.
"If you find one or two that heal up within a week, it may be something as simple as stress, or biting or burning your cheek, and you probably don't need to worry," says Dr. G. Scott Heron, an assistant professor of dermatology at Stanford University. "But if it's recurring all the time -- and if you get multiple sores in your mouth -- you should seek treatment right away from a dermatologist or an oral biologist."
Recurrent blood blisters could signal problems that necessitate medical treatment. The most common of these is oral herpes, a viral infection that flares up periodically and has no known cure. Oral herpes signals its arrival with tingling or discomfort (a prodome) where a blister is about to appear. Soon afterward, blisters erupt on the tongue, the gums, or the cheeks.
Herpes sores commonly appear on the palate, starting as small blisters that soon run together to form one painful, large sore. Flare-ups can be triggered by stress, food allergies, dental treatment, mouth injury, or sunburn on the lips. Taking vitamin C during the prodome may help clear up ensuing sores faster. And taking herpes medication like acyclovir (sold under the brand name Zovirax) will inhibit the reproduction of the virus that causes the blood blisters in the first place.
If herpes isn't the trouble, you may be infected with some other virus. Or you may be having an adverse reaction to medication. You could even have one of the rare genetic disorders (like epidermolysis bullosa, pemphagus, and pemphagoid) that cause blood blisters in the mouth.
For a precise diagnosis, you'll need to see a doctor. In the meantime, if the blisters sting or itch, you may want to treat them with an over-the-counter mouth sore treatment like Orabase or Zilactin.