Introduction
Painful spots in and around the mouth are common, and two of the most frequent culprits — canker sores and cold sores — are often confused for one another. They look somewhat similar and both can be uncomfortable, but they have different causes, locations, and treatments. Telling them apart helps you manage them correctly.
What Canker Sores Are
Canker sores are small, shallow ulcers that appear inside the mouth — on the inner cheeks, tongue, or the soft tissues, but never on the lips externally. They are usually round or oval with a white or yellowish centre and a red border. Importantly, canker sores are not contagious. Their exact cause is not fully understood, but triggers include minor injury to the mouth, stress, certain foods, hormonal changes, and some nutritional deficiencies.
What Cold Sores Are
Cold sores, also called fever blisters, are caused by the herpes simplex virus and typically appear on or around the lips, sometimes on the nose or chin. They begin as a tingling or burning sensation, then form fluid-filled blisters that break and crust over. Unlike canker sores, cold sores are contagious and can spread through close contact, especially when blisters are present. Once infected, the virus stays in the body and can reactivate, often triggered by stress, illness, or sun exposure.
Finding Relief
Most canker sores heal on their own within one to two weeks. Avoiding spicy, acidic, or rough foods, rinsing with warm salt water, and using over-the-counter gels can ease discomfort. Cold sores also tend to resolve on their own, but antiviral creams or medications can shorten an outbreak, particularly if started early at the first tingle. Keeping the area clean and avoiding touching or picking at a cold sore helps prevent spread.
When to See a Professional
Most mouth sores are harmless, but some warrant attention: a sore that does not heal within two weeks, unusually large or frequent sores, severe pain, or sores accompanied by high fever or difficulty eating and drinking. Because a non-healing sore is also part of routine oral cancer screening, a persistent one should be examined. A practice such as MiNa Family Dentistry in Thornhill can evaluate a sore that is not behaving as expected.
Conclusion
Canker sores are non-contagious ulcers inside the mouth, while cold sores are contagious, virus-caused blisters usually on the lips. Both are common and usually heal on their own, with simple measures to ease discomfort. Any sore that lingers beyond two weeks, however, is worth having checked.