Cracked corners of the mouth are almost always a condition called angular cheilitis, a common inflammatory skin problem that develops when moisture gets trapped in the folds at the edges of your lips. Saliva pools in these creases, softens the skin, and creates an environment where fungal or bacterial infections take hold. The result is painful, irritated cracks that can bleed, crust over, and refuse to heal for weeks if the underlying cause isn’t addressed.
What Causes the Cracking
The basic mechanism is simple: saliva collects in the corners of your mouth, breaks down the skin’s protective barrier, and microorganisms move in. The most common culprits are a yeast called Candida and a bacterium called Staphylococcus aureus. One microbiological study found Staph aureus in about 52% of angular cheilitis cases, while Candida tends to dominate in people who wear dentures or have significant facial skin folds around the mouth. In many cases, both organisms are present at the same time.
But the infection is usually the second act. Something has to create the conditions for it first. The most common triggers include:
- Frequent lip licking. Saliva evaporates quickly and leaves the skin drier than before, creating a cycle of moisture and dryness that breaks skin down.
- Ill-fitting dentures. Dentures that don’t sit right can cause the mouth to close unevenly, creating deeper skin folds at the corners where saliva accumulates. Candida counts in denture wearers with angular cheilitis can exceed 8,000 organisms per square centimeter.
- Drooling during sleep. If you sleep with your mouth open or drool onto your pillow, the corners of your mouth stay wet for hours.
- Braces or orthodontic appliances. These can change the way saliva flows and collects around your mouth.
- Aging and skin changes. As you get older, you naturally lose volume in the lower face, which deepens the creases at the mouth corners and makes them more prone to trapping moisture.
Nutritional Deficiencies Play a Bigger Role Than You’d Think
About 25% of all angular cheilitis cases trace back to a nutritional deficiency. The vitamins and minerals most closely linked to mouth corner cracking are iron, riboflavin (B2), niacin (B3), pyridoxine (B6), and B12. These nutrients are essential for maintaining healthy skin and mucous membranes, and when your body runs low on them, the thin, delicate skin at the corners of your mouth is one of the first places to show it.
If your cracked corners keep coming back despite treatment, or if you also have symptoms like fatigue, a sore tongue, or pale skin, a nutritional deficiency is worth investigating. A simple blood test can check your iron and B vitamin levels. This is especially relevant if you follow a restrictive diet, have heavy periods, or have a condition that affects nutrient absorption.
Angular Cheilitis vs. Cold Sores
People often mistake angular cheilitis for cold sores, but they’re different conditions. Cold sores are caused by the herpes simplex virus and are contagious. They typically appear as clusters of small, fluid-filled blisters that can show up anywhere on or around the lips, not just the corners. Angular cheilitis is not contagious. It stays confined to the corners of the mouth and looks more like cracked, soggy, reddened skin than distinct blisters. If you’re unsure which you’re dealing with, a doctor can do a simple swab test to check for herpes or fungal infection.
How It’s Treated
Treatment depends on what’s causing the infection. Since both yeast and bacteria are commonly involved, many treatment protocols use a combination approach: an antifungal cream and an antibacterial cream mixed together and applied to the corners of the mouth twice a day, once in the morning and once before bed. Most mild cases improve within two to three weeks with consistent application.
If the cracks haven’t healed after three weeks, a doctor may add a stronger anti-inflammatory ointment to the mix. However, steroid creams are used sparingly and only for short periods in this area, because the skin around the mouth is thin and sensitive to steroid side effects.
If a nutritional deficiency is driving the problem, no amount of topical cream will keep it from coming back. You’ll need to correct the underlying deficiency through diet changes or supplements.
Preventing It From Coming Back
Angular cheilitis is frustrating because it tends to recur, especially if the conditions that caused it haven’t changed. The most effective prevention strategy is keeping the corners of your mouth dry and protected. Apply a thick barrier like petroleum jelly (Vaseline) to the corners of your mouth before bed, particularly if you tend to drool in your sleep. During the day, resist the urge to lick your lips. If you wear dentures, make sure they fit properly. Poorly fitting dentures are one of the most common and correctable risk factors.
Pay attention to patterns. If the cracking shows up every winter, dry air and chapped skin may be your trigger, and a good barrier cream can prevent it. If it appears after a course of antibiotics, the antibiotics may have disrupted your natural microbial balance and allowed yeast to overgrow. If it keeps returning without an obvious trigger, that’s when checking for nutritional deficiencies or other underlying health conditions becomes important.