Mouth Sores: Types, Causes & When to See a Dentist

The Different Kinds of Mouth Sores

Mouth sores are extremely common and usually harmless but certain types warrant professional evaluation. Canker sores (aphthous ulcers) are small painful ulcers on the inner cheeks, lips, gums, or tongue. They are not contagious, heal within 1 to 2 weeks without treatment, and may be triggered by stress, acidic foods, minor trauma, or nutritional deficiencies. Over-the-counter topical treatments like Orabase or benzocaine provide temporary relief.

Treatment and When to Worry

Cold sores (fever blisters) are caused by herpes simplex virus type 1, appear on the lips or around the mouth, are contagious during the blister phase, and recur periodically throughout life. Antiviral medication like acyclovir or valacyclovir shortens outbreaks if started within 48 hours. Oral thrush is a fungal infection causing creamy white patches that wipe off to reveal red tissue underneath, common in denture wearers, immunocompromised patients, and those taking antibiotics or inhaled steroids. The critical rule is that any mouth sore that does not heal within 2 weeks must be professionally evaluated.

The American Cancer Society reports approximately 54,000 new cases of oral cancer annually, and early detection through biopsy improves 5-year survival from 39 to 84 percent.

Frequently Asked Questions

How long should a mouth sore last?

Most canker sores and cold sores heal within 7 to 14 days. Any sore that lasts longer than two weeks should be examined.

What is the difference between a canker sore and a cold sore?

Canker sores form inside the mouth on soft tissue and are not contagious. Cold sores appear on or around the lips, are caused by the herpes simplex virus, and are contagious.

When is a mouth sore serious?

See a dentist for any sore lasting over two weeks, a lump that does not resolve, a red or white patch, numbness, or difficulty swallowing. These warrant an oral cancer screening.

Finding a Dentist in Huntington Beach

If this sounds like what you are dealing with, the next step is an exam. A dentist can tell in minutes what guesswork cannot, and catching a problem early almost always means a smaller, cheaper fix. Tell us what you need using the form below and we will connect you with a licensed dentist serving Huntington Beach and the surrounding Orange County communities. It is free to use and there is no obligation.

Not sure where to start? Read how to choose a dentist, compare prices in our cost guides, or check signs you need emergency care if the pain is severe.