A blood blister, medically termed an oral hematoma, is a pocket of blood and serum trapped beneath the mucosal surface, the delicate lining of the mouth. This occurs when a small blood vessel just below the surface ruptures, causing blood to leak and pool in the gum tissue. The resulting small sac serves as a protective barrier over the injured tissue as the body begins the natural healing process.
Common Triggers and Causes
Most gum blood blisters result from localized physical trauma. The most common trigger is accidental injury, such as biting down too hard while eating. Sharp edges from hard foods, including crusty bread, chips, or hard candy, can easily scrape and damage the gums, leading to a blister.
Dental instruments and appliances are also sources of irritation. Overly aggressive brushing or flossing, or the constant rubbing from ill-fitting dental devices like dentures or retainers, can injure the delicate gum lining. Blisters may also form following dental procedures, such as an extraction or deep cleaning, due to the necessary pressure applied during treatment.
Beyond physical injury, thermal or chemical burns are factors in blister formation. Consuming very hot liquids or foods can scald the gum tissue, causing the surface layer to separate and trap fluid beneath it. Less frequently, an allergic reaction to certain ingredients in foods or oral hygiene products can lead to blister formation.
Identifying a Gum Blood Blister
A blood blister on the gum is typically easy to identify. Visually, the blister is a raised, bubble-like lesion that ranges in color from dark red to purple or even black, reflecting pooled blood beneath the surface. The darkness of the color often depends on how much the fluid has clotted and the age of the injury.
The size of these blisters can vary widely, from a tiny pinhead to a larger pea-sized bump. When touched with the tongue, the blister feels raised, soft, and smooth. Before the blister ruptures, you may experience mild pain, tenderness, or a feeling of fullness or pressure at the site.
It is important to distinguish a blood blister from other common oral sores, such as canker sores or fever blisters. A canker sore is typically a shallow ulcer that has a white or yellowish center with a red border, and does not contain blood. Blood blisters generally appear suddenly and lack the preliminary tingling sensation often associated with fever blisters.
Self-Care and Healing Time
For most gum blood blisters caused by minor trauma, treatment is often unnecessary, as the lesion will heal on its own. The best course of action is to leave the blister intact and allow it to burst naturally. This prevents the introduction of bacteria and reduces the risk of infection. Attempting to pop or drain the blister with an unsterilized object like a needle should be avoided, as this can delay the healing process.
To keep the area clean and promote healing, gently rinse the mouth with a warm salt water solution. Dissolve about half a teaspoon of salt in a cup of warm water and swish gently to soothe discomfort. During the healing phase, it is beneficial to eat a soft, bland diet and avoid foods that are hard, spicy, or acidic, which might further irritate the blister.
Applying an ice cube or a frozen popsicle to the area for a few minutes can also help reduce swelling and discomfort if applied shortly after the injury occurs. Most small blood blisters resolve completely within a few days to a week. Even larger blisters typically heal entirely within one to two weeks without any scarring.
When to Seek Professional Care
While most gum blood blisters heal quickly, certain signs indicate a need for professional evaluation by a dentist or doctor. You should seek care if the blister is unusually large and interferes with your ability to swallow, speak, or breathe. A visit is also warranted if you notice signs of infection, such as increased pain, redness spreading around the blister, or pus draining from the lesion.
A blister that persists for longer than two weeks or one that frequently recurs should be examined. Persistent or recurring oral lesions may be a sign of an underlying issue, such as chronic irritation from a sharp tooth edge or a less common oral pathology. Although rare, frequent blood blisters can occasionally be associated with systemic conditions, including certain blood disorders or high blood pressure, which require professional diagnosis and management.