Burning corner of mouth
A burning mouth corner is often caused by irritated, cracked skin, but saliva, yeast, allergy, or nutritional problems may also contribute.
The short answer
A burning mouth corner is often caused by irritated, cracked skin, but saliva, yeast, allergy, or nutritional problems may also contribute. The clinical term for inflammation at the mouth angle is angular cheilitis, and treatment depends on which cause is present.
Why can saliva make a mouth corner damp and split?
The mouth angle can stay damp when saliva collects in the fold, then dry and split as the skin moves. Dentists consider local irritation, Candida yeast, bacterial involvement, contact reactions to products, ill-fitting dentures, and less commonly conditions associated with low iron or vitamin B12.
The area may look red, scaly, swollen, crusted, or fissured, and it can sting when you eat acidic or salty food. A similar burning feeling inside the mouth without a visible crack can have a different cause and needs a broader examination.
How can you protect a burning corner of your mouth?
Gently wash the area, pat it dry, and apply a plain protective ointment such as petroleum jelly to reduce contact with saliva. Avoid licking the corner, picking the crust, and using fragranced or medicated creams unless a clinician has advised them.
A dentist examines the crack, teeth, gums, dentures, and oral lining, and may take a swab or arrange blood tests when the appearance or history suggests infection or a nutritional problem. Treatment may involve correcting denture fit, a prescribed antifungal or antibacterial medicine, or treating a contributing skin or medical condition.
When should a dentist examine a recurring mouth-corner split?
Arrange a dental examination if the split keeps returning, does not improve with gentle protection, spreads, produces pus, or makes eating difficult. Recurrent angular cheilitis can persist when saliva exposure, a denture problem, infection, or an underlying deficiency has not been addressed.
Seek prompt care if facial swelling, fever, rapidly worsening pain, trouble swallowing, or trouble breathing occurs. A sore that is firm, bleeds without clear injury, or does not heal also needs direct assessment rather than repeated self-treatment.
What should you ask about the cause of angular cheilitis?
Ask whether the appearance fits angular cheilitis and whether saliva pooling, a denture edge, contact irritation, yeast, or bacteria is most likely. Ask whether you need a swab, a blood test for nutritional causes, or an adjustment to an appliance.
Tell the dentist when it began, whether one or both corners are affected, which products touch the area, and whether it has happened before. Ask how long to use any prescribed treatment and what change should prompt a review.
Frequently asked questions
Can a burning mouth corner be caused by a fungal infection?
Yes. Candida yeast can contribute, especially when the corner stays moist, but the appearance alone cannot confirm the cause; a dentist may prescribe an antifungal treatment after examination.
Should I keep putting lip balm on the cracked corner?
Use a plain, fragrance-free protective ointment rather than a product that stings or contains several active ingredients, and arrange an examination if the problem persists or returns.
Why does the crack keep coming back?
Recurrence can reflect ongoing saliva exposure, denture or bite-related irritation, yeast or bacterial involvement, contact sensitivity, or an unrecognised nutritional or medical contributor.
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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.