Cracked sore corners of my mouth
The skin at one or both corners of your mouth is split, red and sore. It stings when you yawn, laugh, smile or bite into food. A crack may crust over at night, then tear open again in the morning.
The medical name is angular cheilitis. It just means sore, inflamed mouth corners. It is common, and it is not a sign of poor hygiene.
The corners are a fold of skin that stays damp. Damp skin gets soft and breaks. Once it breaks, germs that live in every mouth can move in and keep it sore.
When to see someone
See a doctor or dentist if the cracks last more than two weeks.
Go sooner, within a day or two, if you see a yellow or honey-colored crust, redness spreading onto your cheek, swelling, or pus. That can be a bacterial infection that spreads to others.
Go to urgent care or an emergency room if you have a fever with a hot, swollen, spreading red face, or if the swelling reaches your eye. Also go if your face swells so much that swallowing or breathing feels hard.
Book a doctor if you have white patches inside your mouth that will not wipe off, or pain deep in your throat when you swallow. That may be thrush spreading past the mouth.
See a doctor if you also feel very tired, look pale, feel breathless, or your tongue is sore and smooth. These point to low iron or low B12, and a blood test can check it.
See a dentist if you wear dentures, have missing or worn teeth, or the cracks come back again and again. The fit and bite may need changing.
Get checked early if you have diabetes, use a steroid inhaler, take medicine that lowers your immune system, or are having cancer treatment.
Ask for an urgent appointment if any mouth sore, lump or white or red patch has not healed in three weeks. A doctor or dentist needs to look at it, even if it does not hurt.
For a baby, see a doctor if they will not feed, are drooling more than usual, or have white patches in the mouth.
Why it happens
Spit pools in the corner folds and sits there for hours. Saliva has enzymes that slowly break down skin. Wet, softened skin splits far more easily than dry skin.
Once there is a split, two germs often take hold. One is yeast, the same kind behind oral thrush. The other is a common skin bacteria that leaves a yellow, honey-like crust.
Some things keep the corners wet all day. Lip licking, drooling in sleep, braces, a pacifier or thumb, and mouth breathing all do this. So do dentures that no longer fit, because they let the face shorten and the folds deepen.
Low iron, low B vitamins, low folate or low zinc can also play a part. Skin heals slower when those are low. That is why some cracks keep coming back even when you keep them dry.
What else it could be
Sore mouth corners have several causes, and they need different care. Getting the cause right matters more than picking a remedy.
Yeast (thrush) type: the corners are red, raw and often on both sides. You may also see white patches inside your cheeks or on your tongue. The patches do not wipe away easily, and the skin under them looks red.
Bacterial type: the crack has a yellow or honey-colored crust. Redness may spread out onto the skin. This kind can spread to other people by touch and usually needs a doctor.
Cold sore: this is not the same thing. A cold sore starts with a tingle or itch in one spot. Small blisters come up, break, scab, and clear in about 10 days, often in the same place each time.
Chapped lips: cold, wind or dry air dry the whole lip, not just the corners. The lips feel tight and peel all over. Corner cracks from chapping heal fast once you add a barrier.
Allergy or irritation: toothpaste, lip balm, nail polish, mango, cinnamon flavor or metal can inflame the lips. The itch and redness often spread past the corners onto the skin around the mouth. It clears when you stop the product.
Nutrition or health link: cracks that keep returning may point to low iron or low B12. Look for tiredness, pale skin, a sore smooth tongue or breathlessness. Diabetes, steroid inhalers and a weak immune system also make yeast more likely.
Denture or bite change: if your teeth are worn or missing, your chin sits closer to your nose. That deepens the corner folds and traps spit. The crack will keep coming back until the fit is sorted out.
How to read the grades below
The options below come from our page on Oral Thrush. Each one carries two labels.
The first label is the evidence grade. A means strong trials in people, B means smaller or mixed studies, and C means early or limited findings. D means lab work only, and “insufficient” means the research cannot settle it yet.
The second label is the traditional tier. T3 means long use in more than one tradition, T2 means long use in one, and T1 means known use. T0 means no such record.
These grades come from research on Oral Thrush, the parent Health Topic, not on cracked sore corners of my mouth.
A grade tells you how strong the research is, not how well something will work for you. Talk to a doctor or pharmacist before you start anything, above all if you take other medicines.
What to try first
Step one is to keep the corners dry. Pat them dry after every drink and meal. Try hard not to lick them, even though it feels good for a moment.
Step two is a barrier at night. A thick, plain ointment with no scent and no flavor is one option. It blocks spit from soaking the skin while you sleep.
Step three is to look for the source of the wet. Check that dentures still fit. Treat a blocked nose so you can breathe through it, and check braces or a night guard.
If thrush is part of your picture, the options below were graded for oral thrush. They aim at yeast in the mouth, not at the crack itself.
Saltwater Rinse has an evidence grade A, traditional tier T3. Stir half a teaspoon of salt into a cup of warm water. Swish and spit two or three times a day, and do not swallow it.
Oil Pulling has an evidence grade B, traditional tier T2. You swish a spoon of edible oil around the mouth, then spit it into the bin. Keep the oil off the cracks if it stings.
Probiotics (Lactobacillus plantarum P8) have an evidence grade C, traditional tier T0. These are taken by mouth as a drink or capsule. The proof here is early and thin.
Coconut Oil has an evidence grade insufficient, traditional tier T3. Turmeric has an evidence grade insufficient, traditional tier T3. Caprylic acid has an evidence grade insufficient, traditional tier T0, so there is not enough proof to lean on any of these three.
Cinnamon Essential Oil has an evidence grade D, traditional tier T1. Never put a neat essential oil on split skin. It can burn, and cinnamon is a common cause of lip rash.
None of these will fix a crack that is bacterial, or one caused by a bad denture fit. Those need a doctor or dentist.
How long it takes
If the cause is just damp and rubbing, you should feel better in 3 to 7 days. Keeping the corners dry and using a barrier at night does most of the work. Full healing often takes one to two weeks.
If yeast or bacteria have set in, home care alone may stall. A prescribed cream usually starts to help within a few days. Ask for one if there is no change after two weeks.
If low iron or low B12 is behind it, healing takes longer. Blood levels need weeks to build back up. The cracks may keep returning until that is treated.
If dentures or missing teeth are the cause, the cracks will keep coming back. They settle only after the fit is adjusted.
