Cracked Corners of the Mouth: What Causes Them and How to Heal Them

Once the weather turns cold and the heat comes on, we start seeing a familiar complaint in our Dandridge and Jefferson City offices: painful cracks at the corners of the mouth. They sting when you smile, burn when you eat something salty or acidic, and seem to split open again just when they start to heal.

This condition has a name, angular cheilitis, and it is far more common than most people realize. The good news is that it is rarely serious. The key is figuring out why it keeps happening so it does not keep coming back.

Why the Corners of the Mouth Crack

The corners of your lips are a natural fold where skin meets the moist lining of the mouth. When saliva collects there, the skin stays wet, softens, and breaks down. Once the skin cracks, yeast and bacteria that normally live in the mouth can move in, and the area becomes inflamed and slow to heal.

Several things make that cycle more likely:

• Lip licking. Licking dry lips feels like relief, but saliva evaporates fast and leaves the skin drier than before. In cold weather this habit is one of the most common triggers.
• Dry winter air. Low humidity outdoors and forced-air heat indoors pull moisture from the lips and skin.
• Drooling during sleep. People who sleep with their mouth open, often because of congestion, may wake up with wet corners every morning. Our article on mouth breathing explains why this matters for your teeth too.
• Yeast and bacteria. Candida, the same yeast that causes oral thrush, and staph bacteria are frequent players in cracks that will not heal.
• Dry mouth. Many medications reduce saliva, which leads people to lick their lips more often. See our guide to medications that cause dry mouth.

The Dental Connection Most People Miss

As a dentist, this is the part I want patients to hear. Angular cheilitis is often a sign that something has changed in the way your mouth closes.

Worn or loose dentures

Dentures help hold the lower face at the right height. As dentures wear down and the jawbone underneath slowly shrinks, the mouth closes further than it should. That creates deeper folds at the corners where saliva pools. Many denture wearers who struggle with constant cracking simply need their dentures relined or replaced. Dentures that are not cleaned well can also harbor yeast that feeds the problem.

Missing back teeth

When back teeth are lost and not replaced, the bite can collapse slightly over time. The result is the same deepened fold at the corners of the mouth. Replacing missing teeth with a bridge, partial, or dental implants can restore the proper support.

Orthodontic appliances and mouthguards

Retainers, aligners, and sports guards can increase saliva flow or rub the corners of the mouth, especially in kids and teens.

When It Points to Something Else

Most cases are local and simple. Sometimes, though, cracked corners that keep returning point to a nutritional or medical issue. Low iron, low B vitamins such as B2, B12, or folate, and low zinc have all been linked to angular cheilitis. Diabetes, which affects healing and increases yeast growth, can also play a role. If you have recurring cracks along with fatigue, a sore or smooth tongue, or other symptoms, talk with your physician about simple blood work.

Cracks that persist for weeks, bleed easily, have a crusty yellow appearance, or appear alongside sores elsewhere in the mouth should be examined. We check the lips, corners of the mouth, and all oral tissues during every oral cancer screening.

How to Help Cracked Corners Heal at Home

• Stop licking. Carry a plain lip balm or petroleum jelly instead, and apply it to the corners as well as the lips.
• Use a barrier at night. A thin layer of plain petroleum jelly or zinc oxide ointment before bed helps protect against drool.
• Skip flavored and scented balms. Mint, cinnamon, and fragrance can irritate already broken skin.
• Add humidity. A bedroom humidifier during heating season can make a real difference.
• Clean dentures daily and take them out at night. Soak them in a denture cleaner, never sleep in them, and brush your gums and tongue.
• Stay hydrated. Drinking water throughout the day helps with dry mouth and dry lips.

If the cracks do not improve after a week or two of protecting the area, there is likely an infection involved. Your dentist or doctor can recommend an antifungal or antibacterial treatment based on what is going on. Avoid using steroid creams without guidance, since they can make a yeast infection worse.

Preventing It From Coming Back

The real fix is addressing the cause. For many patients that means a denture reline, replacing missing teeth, treating dry mouth, or breaking the lip licking habit. For others it means checking iron or vitamin levels. Once the underlying issue is handled, most people stop getting cracked corners altogether.

Common Questions

What causes cracks at the corners of the mouth?

The most common cause is saliva collecting in the corners of the mouth, which breaks down the skin and lets yeast or bacteria grow. Lip licking, dry winter air, drooling during sleep, worn dentures, and low iron or B vitamins can all contribute.

Is angular cheilitis contagious?

Angular cheilitis is generally not considered contagious in everyday contact. It usually develops from conditions in your own mouth and skin, such as moisture, yeast, or bacteria that are already present.

Can dentures cause cracked corners of the mouth?

Yes. Worn or poorly fitting dentures can let the mouth close too far, creating deep folds where saliva pools. Dentures that are not cleaned well can also carry yeast. A reline or new denture often solves the problem.