Dry, cracked corners of the mouth are almost always a condition called angular cheilitis. It starts when moisture collects in the creases at the edges of your lips, softens the skin, and then the skin dries out and breaks down. That cycle of wetting and drying creates small fissures that can become red, flaky, sore, or crusty. The causes range from simple habits like lip-licking to nutritional deficiencies and fungal infections, and figuring out which one applies to you is the key to making it stop.
How the Damage Happens
The corners of your mouth are uniquely vulnerable. Unlike the rest of your skin, this area sits at a junction between the moist lining inside your mouth and the drier skin of your face. Saliva naturally pools in these creases, especially if the folds are deep. When saliva sits on the skin repeatedly, it softens and breaks down the outer barrier, a process called maceration. Once that protective layer is compromised, the skin cracks as it dries. Those tiny cracks then trap even more moisture, creating a cycle that’s hard to interrupt on its own.
This is why angular cheilitis tends to get worse before it gets better. The damaged, soggy skin becomes an ideal environment for yeast (most often Candida) and bacteria (most often Staphylococcus) to move in. Once infection takes hold, the redness deepens, crusting develops, and the splits at the corners may bleed or ooze when you open your mouth wide.
The Most Common Causes
Lip-Licking and Other Habits
The single most common everyday trigger is repeatedly licking your lips. It feels like it helps in the moment, but saliva evaporates quickly, pulling moisture out of the skin with it. Habitual lip-licking, thumb-sucking in children, smoking, and even aggressive dental flossing all increase saliva exposure at the mouth corners and can kick off the maceration cycle.
Cold, Dry Weather
Environmental exposure to dry heat or cold air strips moisture from the skin faster than it can be replaced. Winter air, forced heating indoors, and wind all contribute. If you notice the problem flares seasonally, this is likely a major factor.
Allergic Reactions to Lip Products
Contact dermatitis accounts for up to 22% of angular cheilitis cases. Common culprits include toothpaste, mouthwash, lip balm (particularly expired products whose sunscreen ingredients break down), lip cosmetics, acne products, and chewing gum. Nickel from orthodontic braces is another frequent trigger. If the dryness started after you switched a product, that’s worth investigating.
Nutritional Deficiencies
Up to 25% of angular cheilitis cases are linked to low iron or B vitamin levels. The specific nutrients most often involved are vitamin B12, folate, riboflavin (B2), iron, and zinc. General protein malnutrition can also play a role. If you’re eating a restricted diet, have digestive issues that affect absorption (like Crohn’s disease or chronic gastritis), or have been losing weight rapidly, a deficiency is a realistic possibility.
Fungal and Bacterial Infection
Many cases of angular cheilitis involve Candida yeast, the same organism behind oral thrush. Bacteria, particularly staph, can also colonize the cracked skin. Sometimes both are present at once. Diabetes raises the risk of Candida overgrowth specifically because higher glucose levels in saliva give the yeast more fuel and help it stick to the tissue. People who use inhaled steroids (common with asthma) or oral steroids are also more susceptible, since these medications suppress the local immune response that normally keeps yeast in check.
Structural and Dental Risk Factors
The shape of your face and the condition of your teeth play a bigger role than most people realize. When teeth are severely worn down, missing, or replaced by ill-fitting dentures, the lower face loses vertical height. The upper lip then overhangs the lower lip more than it should, deepening the creases at the corners and creating a pocket where saliva collects constantly. This is one of the main reasons angular cheilitis is more common in older adults.
Natural aging contributes too. As skin loses firmness, the lines running from the corners of the mouth downward (sometimes called marionette lines) deepen, creating the same saliva-trapping folds. Rapid weight loss and smoking both accelerate this loss of skin elasticity. If you’ve recently lost a significant amount of weight and noticed the problem for the first time, the change in facial volume may be part of the explanation.
What It Feels Like
Angular cheilitis typically starts as tightness or dryness at one or both corners of the mouth. You might notice the skin looks slightly red or feels rough. Within a few days, small cracks or splits develop. These can sting when you eat acidic or salty foods, and opening your mouth wide (yawning, eating a sandwich, laughing) may re-open the fissures and cause sharp pain. In more advanced cases, the area becomes crusty, scaly, or swollen, and may bleed. Some people develop the problem on one side only; others get it on both.
It’s easy to confuse angular cheilitis with a cold sore, but the two are quite different. Cold sores are caused by the herpes simplex virus, usually appear as fluid-filled blisters on or near the lip (not specifically in the crease), and tend to tingle or burn before they become visible. Angular cheilitis stays in the corners, doesn’t blister in the same way, and is not contagious.
How to Treat It
Treatment depends on what’s driving the problem. For mild cases triggered by weather or lip-licking, a thick barrier ointment like petroleum jelly or a zinc oxide cream applied to the corners several times a day can break the wet-dry cycle. The goal is to keep saliva off the damaged skin so it can heal. Avoid flavored or medicated lip balms that might contain irritating ingredients.
If the area is red, swollen, or crusty, a yeast or bacterial infection is likely involved. Over-the-counter antifungal creams designed for skin yeast infections can help with Candida. When bacteria are the main issue, a topical antibiotic ointment is more appropriate. In many cases, a doctor will prescribe a combination approach that addresses both yeast and inflammation at once. Mild cases often improve within one to two weeks with consistent treatment, but stubborn or recurring episodes may take longer, especially if an underlying cause like a nutritional deficiency or poorly fitting dentures hasn’t been addressed.
For deficiency-related cases, correcting the shortfall is essential. No amount of topical cream will permanently resolve angular cheilitis if your body is low on iron, B12, or zinc. A simple blood test can identify the specific gap. Once supplementation begins, the mouth corners typically improve as levels normalize, though this can take several weeks.
Preventing It From Coming Back
Angular cheilitis recurs easily because the anatomy of your mouth corners doesn’t change. A few practical steps reduce the odds:
- Keep the corners dry and protected. Apply petroleum jelly or a plain barrier cream before bed and before going outside in cold or windy weather. This prevents saliva from sitting on the skin.
- Stop licking your lips. This is the hardest habit to break, but it’s also the most impactful for people whose cheilitis is behavior-driven.
- Check your products. Switch to a gentle, unflavored toothpaste and a fragrance-free lip balm. If you wear braces, nickel sensitivity is worth discussing with your orthodontist.
- Address dental fit. If you wear dentures, have them evaluated for proper fit. Even small adjustments that restore the vertical height of your bite can eliminate the skin folds where saliva pools.
- Watch your diet. Leafy greens, legumes, eggs, meat, and fortified cereals cover the B vitamins, iron, and zinc most commonly linked to angular cheilitis. If you follow a vegan or very restrictive diet, targeted supplementation may be worthwhile.
If your mouth corners crack repeatedly despite these measures, or if you also have symptoms like fatigue, unusual thirst, or digestive problems, the issue may point to an underlying condition like diabetes, an autoimmune disorder, or a malabsorption problem that needs its own workup.