Burning corner of mouth

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.

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.

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.

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.