Cracks at the corners of the mouth that last more than a couple of weeks are often more than dry skin. Angular cheilitis, the medical name for these sore, split and sometimes crusted corners, usually needs two things to happen together: saliva sitting in the crease, and yeast or bacteria growing in the softened skin. Treating the infection settles most episodes. Finding out why the crease stays wet is what stops them coming back, and quite often that reason is in the mouth.
Start with the skin, then look for the cause
For a first, mild episode, a pharmacist can usually recommend an antifungal cream to apply to the corners, sometimes combined with a mild anti-inflammatory ingredient. Between applications, a thin layer of a plain barrier ointment such as petroleum jelly keeps saliva off the healing skin, particularly overnight. Many cases improve noticeably within one to two weeks.
When bacteria such as staphylococcus are involved, which is common, an antifungal alone may not be enough, and a doctor or dentist may suggest a cream that also covers bacteria. If there is no clear improvement after two weeks, or the corners keep splitting again after they heal, it is time to look for what is driving it.
A shortened bite is a frequent dental reason
The distance between the nose and chin when the teeth are together is set by the height of the back teeth. When teeth wear down from grinding, when several back teeth are lost, or when a denture gradually wears and the gum beneath it shrinks, that distance can shorten. The lips then roll in a little at the corners, the fold deepens, and saliva collects there for hours at a time.
This is a common reason angular cheilitis keeps returning in older adults and denture wearers. Creams treat the surface, but the deep fold rebuilds the same damp conditions as soon as treatment stops. A dentist can check whether bite height has dropped by looking at tooth wear, the fit of any denture and the way the lips meet at rest.
What can be done about lost height
For denture wearers, a reline adds new material to the fitting surface so the denture sits properly again, and a remake is often better when the teeth on the denture themselves are worn flat. Natural teeth that have worn down can be built back up with fillings, onlays or crowns, depending on how much tooth is left. Our guide to inlays, onlays, crowns and fillings explains the differences, and the dentures guide covers relines and replacements. Restoring height is a larger decision than buying a cream, so it is usually considered when angular cheilitis keeps recurring or when worn teeth or a loose denture need attention anyway.
Other things that keep the corners wet or weak
Several other factors can contribute, and more than one may be present:
- Licking the lips or corners, which is common in cold, dry weather and quickly undoes treatment.
- Drooling during sleep, and in young children, a dummy or thumb-sucking habit.
- Oral thrush or denture stomatitis, where yeast is already growing inside the mouth and spreads to the corners. Our article on oral thrush in adults covers this.
- Low iron, B vitamins, folate or zinc, which can make the skin at the corners more fragile and slow healing.
- General health factors such as diabetes, a weakened immune system (including during cancer treatment), some acne medicines that dry the skin, and allergy to ingredients in lip products or toothpaste.
A GP is the right person to check blood levels or general health causes, especially when cracked corners come with tiredness, a sore smooth tongue or other symptoms.
Telling it apart from a cold sore
A cold sore is caused by the herpes simplex virus. It often starts with tingling, forms a cluster of small blisters on or near the edge of the lip, then crusts over and usually heals within about ten days, and it can spread to other people. Angular cheilitis sits right in the crease at the corner, looks cracked and red rather than blistered, and is not usually considered contagious. Antifungal creams will not help a cold sore, and antiviral creams will not help angular cheilitis, so getting this right matters. Our guide to cold sores versus mouth ulcers has more detail.
Questions we are often asked
Does a vitamin supplement fix it?
Only if a deficiency is actually present. Taking supplements without a reason is unlikely to help, so if you suspect a deficiency, ask your GP about a blood test first.
Who should I see first?
A pharmacist is a reasonable first stop for a single mild episode. See a dentist if it keeps returning, if you wear a denture or if your teeth are noticeably worn. See a GP if you feel unwell, have other symptoms, or it persists despite treatment.
Can it leave a scar?
Most cases heal without any lasting mark. Long-standing cracking can occasionally leave a small line in the crease, which is another reason to treat the cause early.
If the corners of your mouth keep cracking, our team at Lumi Dental can check whether worn teeth, an old denture or thrush in the mouth is part of the cause. See our current deals page or read about general dental care at our Melrose Park practice.
This article is general information and not a substitute for personal dental or medical advice.
