A canker sore is a small, shallow lesion that develops on the soft tissues inside the mouth, such as the inner cheeks, lips, tongue, or the base of the gums. These painful sores typically appear with a white or yellowish center and a distinct red border. Unlike cold sores, which are caused by the contagious herpes simplex virus and appear on the outside of the lips, canker sores are not viral or contagious. Most minor canker sores resolve on their own within one to two weeks, but they can make eating and talking extremely uncomfortable.
Addressing the Impulse: Why Manipulation is Harmful
The discomfort of a canker sore may create an impulse to “pop” or manipulate the lesion, but this action is strongly advised against. A canker sore is an open ulcer, not a fluid-filled blister that can be drained like a pimple. Attempting to rupture the sore will not provide relief or speed up the healing process.
Physically disrupting the ulcer breaks the delicate layer of tissue attempting to form over the wound, exposing sensitive underlying nerve endings. This exposure leads to a significant increase in pain and sensitivity, making the lesion much worse. The mouth contains a high concentration of bacteria, and opening the sore creates a direct pathway for microbes to enter the wound. This increases the risk of a secondary bacterial infection, which can lead to pus formation, increased inflammation, and a prolonged healing time.
Safe Home Management and Over-the-Counter Relief
The primary goals of managing a canker sore at home are to relieve pain, reduce inflammation, and protect the ulcerated tissue to encourage natural healing. Simple home remedies can be effective. Rinsing the mouth with a salt water solution (one teaspoon of salt in a half-cup of warm water) helps cleanse the area and reduce swelling. A baking soda rinse (one teaspoon of baking soda dissolved in warm water) can help neutralize acids in the mouth and soothe the inflamed tissue.
Over-the-counter products offer relief by either numbing the area or creating a protective barrier. Topical anesthetics like benzocaine or lidocaine provide temporary pain relief by numbing the nerve endings directly at the site of the sore. Protective pastes, often containing cellulose gum, adhere to the sore, shielding it from irritation caused by food, saliva, and accidental contact. Applying milk of magnesia a few times a day can also serve as a soothing, protective coating.
When to Seek Professional Medical Attention
While most canker sores are minor and heal without intervention, certain symptoms indicate a need for professional medical evaluation. Consult a doctor or dentist if a sore is unusually large (more than one centimeter in diameter) or causes extreme difficulty with eating or swallowing. A persistent sore that lasts for two weeks or longer without healing requires assessment to rule out other potential causes.
Frequent recurrence, or outbreaks that happen multiple times a year, also warrant medical attention. Additionally, seek care if the canker sore is accompanied by systemic symptoms such as a high fever, diarrhea, headache, or a skin rash. Sores extending onto the outer surface of the lips should also be checked, as this location is characteristic of a cold sore requiring different treatment.