Mouth crease sore
A sore at the corner of the mouth may come from moisture and saliva, irritation, contact dermatitis, infection, a denture, or a local dental problem.
The short answer
The corner is the oral commissure. Repeated wetting, lip licking, reduced bite height, yeast, and bacteria can cause cracking, crusting, burning, and tenderness.
Why can a sore mouth corner become cracked and tender?
Keep it gently clean and dry, avoid licking or picking, and pause products that sting. A clinician can inspect the skin, teeth, oral lining, and denture fit before choosing treatment.
How can you keep a mouth-corner sore clean and dry?
Seek care if it lasts, recurs, spreads, bleeds, or has pus or marked swelling. Urgent care is needed for fever or trouble swallowing.
When should a sore in the mouth crease be checked?
Ask whether it is angular cheilitis, contact irritation, or another lesion, and whether a denture or bite issue contributes.
Frequently asked questions
Can home care replace an examination?
Home care supports hygiene but cannot diagnose or treat problems such as calculus, decay, or an abscess.
What if symptoms worsen?
Arrange prompt dental care for worsening pain, swelling, drainage, or persistent bleeding.
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Who wrote this page
This library is published by Dental Nation, a licensed dental group practising in the United Arab Emirates. Pages are written and overseen by the same clinical team that treats patients in our clinics, and are held to a fixed editorial standard for safety and accuracy.
This page is patient education, not medical advice, and cannot replace an examination. Anything urgent — facial swelling, trauma, uncontrolled bleeding or severe pain — needs a dentist or emergency care now.