Corner of mouth sore
A sore at the mouth corner is often angular cheilitis from moisture and irritation, but infection or a skin condition may be involved.
The short answer
A sore at the mouth corner is often angular cheilitis, an inflammation in the fold where the lips meet.
What is the direct answer?
What does this question mean?
The lip corner stays wet with saliva and can crack, allowing irritation or yeast and bacteria to inflame the skin. Denture fit, lip licking, nutritional problems, and eczema can contribute.
What can you do next?
Keep the area gently clean and dry, apply plain petroleum jelly as a barrier, and avoid licking or picking it. A clinician may inspect the crack and prescribe an antifungal, antibacterial, or anti-inflammatory treatment only when its cause is clear.
When should you seek dental care?
See a dentist or doctor if it lasts beyond several days, recurs, spreads, forms blisters, or makes eating difficult. Prompt care is important for facial swelling, fever, or a rapidly spreading infection.
What should you ask the dentist?
Ask whether the finding is angular cheilitis, herpes, contact dermatitis, or another lesion, and whether a swab or medical review is needed. Ask which barrier or prescribed medicine fits the cause and how long to use it.
Frequently asked questions
Could this be caused by something other than the obvious explanation?
Yes. The examination should separate local irritation from tooth disease, infection, medication effects, and conditions outside the mouth.
What happens at the dental visit?
The clinician reviews the history, examines the tissues and teeth, and uses targeted measurements or imaging when those findings are needed.