Pain at the corners of your mouth is most often caused by a condition called angular cheilitis, where the skin cracks, reddens, and becomes irritated right where your upper and lower lips meet. It can affect one side or both, and it tends to sting or burn every time you open your mouth to eat, talk, or yawn. The good news is that it’s not contagious and is usually treatable at home once you understand what’s driving it.
How Saliva Breaks Down the Skin
The underlying cause in most cases is surprisingly simple: saliva pools in the corners of your mouth and stays there too long. Your saliva contains digestive enzymes designed to start breaking down food, and those same enzymes will irritate skin tissue when they sit on it for extended periods. The constant moisture softens and weakens the outer layer of skin at the corners of your lips, creating a condition similar to what happens when you wear a wet bandage for too long.
Once that protective skin barrier breaks down, the area becomes inflamed and cracked. This damaged skin is then vulnerable to infection by organisms that already live harmlessly on your skin and in your mouth, particularly yeast (a type of fungus) and certain bacteria. So the typical progression is moisture damage first, followed by infection that makes the soreness worse and harder to heal.
Common Reasons Saliva Collects There
Anything that changes the shape of your mouth or increases moisture at the corners can set this cycle in motion. Some of the most common triggers include:
- Lip licking. Habitually licking your lips, especially in cold or dry weather, deposits saliva repeatedly on already-irritated skin.
- Ill-fitting dentures or braces. Dental appliances that don’t sit properly can alter how your lips close, creating deeper folds at the corners where saliva accumulates.
- Age-related skin changes. As skin loses elasticity over time, the corners of the mouth naturally develop deeper creases that trap moisture more easily.
- Drooling during sleep. If you sleep with your mouth open or drool at night, saliva sits on the corners of your mouth for hours.
- Thumb sucking or pacifier use. In children, these habits keep the mouth corners chronically wet.
Nutritional Deficiencies That Play a Role
Cracked mouth corners can also signal that your body is low on certain nutrients. Iron deficiency is one of the more common culprits, along with several B vitamins, particularly B2 (riboflavin), B3 (niacin), B6, and B12. Zinc deficiency can contribute as well. These nutrients all play roles in maintaining healthy skin and mucous membranes, so when levels drop, the thin, delicate skin at the lip corners is often one of the first places to show damage.
This is especially worth considering if your mouth corners crack repeatedly without an obvious cause like lip licking or dental issues, or if you follow a restricted diet, have a digestive condition that affects nutrient absorption, or have recently lost weight. A simple blood test can check for these deficiencies.
Is It a Cold Sore or Angular Cheilitis?
Many people worry that a sore near their mouth is a cold sore (caused by the herpes virus), and the two can look similar at first glance. But there are reliable differences. Angular cheilitis stays confined to the corners of the mouth, produces dry, red, flaky, cracked skin, and does not cause blisters. Cold sores typically appear on or near the lip itself (not just the corners), start as a cluster of small fluid-filled blisters, and often tingle or itch before they become visible.
Angular cheilitis is not contagious and won’t spread beyond the lip corners. Cold sores are highly contagious, especially when blisters are open. If you see clear blistering or the sore spreads along the lip border, you’re more likely dealing with a cold sore than angular cheilitis.
How to Treat Cracked Mouth Corners
The first and most important step is keeping the area dry and protected. Applying a thick barrier ointment like petroleum jelly (Vaseline) to the corners of your mouth creates a physical shield between your skin and saliva. This alone can allow mild cases to heal within a week or two. Reapply after eating, drinking, and before bed.
If the cracking doesn’t improve with a barrier ointment, the damaged skin has likely picked up a fungal or bacterial infection. Over-the-counter antifungal creams designed for skin yeast infections are the typical next step. Look for products containing clotrimazole or miconazole, apply a thin layer to the corners of the mouth two to three times per day, and continue for several days after the skin looks healed to prevent the infection from bouncing back.
For cases that resist antifungal treatment, a bacterial infection may be involved instead of (or in addition to) yeast. A healthcare provider can determine which type of infection is present and prescribe the appropriate topical treatment. Persistent or frequently recurring cases sometimes warrant blood work to check for underlying nutritional deficiencies or immune system issues.
Preventing It From Coming Back
Angular cheilitis has a frustrating tendency to recur, especially if the original cause hasn’t been addressed. A few practical habits make a real difference. Stop licking your lips, even when they feel dry. Use a barrier ointment before sleep if you tend to drool at night. If you wear dentures, have them checked for proper fit regularly, since even small changes in your gum tissue over time can create new gaps where saliva collects.
Staying on top of nutrition helps too. A balanced diet that includes leafy greens, eggs, meat or fortified cereals, and legumes covers the B vitamins, iron, and zinc that keep your skin resilient. If you’ve been diagnosed with a deficiency, supplementation can resolve recurring mouth corner cracking that doesn’t respond to topical treatment alone. In dry or cold weather, applying petroleum jelly to the mouth corners as a preventive measure, before any cracking starts, can stop the cycle before it begins.