Cracked mouth corners are almost always a condition called angular cheilitis, an inflammatory skin breakdown right at the crease where your upper and lower lips meet. About 25% of cases trace back to a nutritional deficiency, but the rest involve a mix of moisture, infection, and mechanical factors that keep the skin from healing. It looks alarming, but it’s common, not contagious, and very treatable once you address the underlying cause.
What Actually Happens to the Skin
The corners of your mouth sit in a natural fold where moisture collects easily. Saliva pools in that crease, and when it evaporates, it strips the skin of its protective oils. The repeated wet-dry cycle softens and weakens the skin, a process called maceration, where the tissue turns pale, soggy, and fragile. Once the skin barrier breaks down, it cracks open.
Those cracks then become entry points for microbes, most commonly a yeast called Candida or bacteria like Staph. The infection deepens the damage, and the sore becomes red, crusty, or swollen. Opening your mouth to eat or talk pulls the cracked skin apart, so the wound keeps reopening instead of healing. This is why angular cheilitis can drag on for weeks if you don’t interrupt the cycle.
The Most Common Causes
Lip Licking and Saliva Exposure
The most frequent trigger is simple and mechanical: saliva sitting in the corners of your mouth. Licking your lips feels like it helps dry, tight skin, but it makes everything worse. Saliva contains digestive enzymes that irritate already-damaged tissue, which causes more cracking, which makes you lick more. It’s a self-reinforcing loop that can keep the condition going indefinitely.
Nutritional Deficiencies
Nutritional gaps account for roughly 25% of all angular cheilitis cases. The key nutrients involved are iron and several B vitamins: riboflavin (B2), niacin (B3), pyridoxine (B6), and B12. These nutrients are essential for maintaining healthy skin and mucous membranes, so when levels drop, the delicate skin at the lip corners is one of the first places to show it. If your cracking keeps coming back despite good hygiene and moisture control, a blood test checking iron and B vitamin levels is a reasonable next step.
Dentures and Changes in Facial Structure
Ill-fitting dentures are a well-known cause, especially older dentures that have lost vertical height over time. When dentures sit too low, the lower face collapses slightly, creating deeper skin folds at the mouth corners. Those deeper folds trap more saliva and stay damp longer. Age-related bone loss in the jaw can produce the same effect even without dentures, as can significant weight loss that changes facial contours.
Yeast and Bacterial Infection
Candida yeast is the most common infectious culprit, which is why angular cheilitis is more frequent in people who wear dentures (yeast thrives under dental appliances), use inhaled steroid medications, have diabetes, or have a weakened immune system. Bacterial infection, particularly Staph, can also colonize the cracked skin. Sometimes both organisms are present at the same time, which is why treatment occasionally needs to address fungal and bacterial infections separately.
Contact Irritants and Allergies
Certain products that touch the lip corners can trigger or worsen the condition. Toothpaste ingredients, lip balm fragrances, or cosmetics are common offenders. If your cracking started after switching to a new product, that’s worth investigating. Allergy medication or simply eliminating the product may resolve it.
How It Differs From a Cold Sore
People often confuse angular cheilitis with cold sores because both involve painful sores near the mouth. Cold sores typically start with tingling or itching, then develop into a cluster of small blisters that weep, scab over, and heal over about 7 to 10 days. They can appear anywhere on or around the lips. Angular cheilitis starts as dry, irritated, cracked skin specifically at the corners of your mouth. It doesn’t blister the same way, and it won’t heal on its own if the underlying cause persists. Cold sores are caused by the herpes simplex virus and are contagious. Angular cheilitis is not contagious.
How It’s Treated
Treatment depends on what’s driving the problem, but for most people it involves two things: killing any infection and protecting the skin so it can heal.
For fungal infections, an over-the-counter antifungal cream containing miconazole, clotrimazole, or terbinafine applied to the corners of the mouth twice a day for 10 to 14 days is the standard approach. If bacteria are the primary issue, a prescription antibacterial cream applied several times a day for about a week is typical. Your doctor or dentist can usually tell by looking at it which type of infection is involved, though a swab test can confirm.
Between applications of any medicated cream, a petroleum-based ointment like Vaseline or Aquaphor serves as a barrier that shields the cracked skin from saliva. This is a simple step that makes a real difference, because it breaks the moisture cycle that keeps the skin from healing. Combined steroid and antimicrobial creams are rarely necessary for routine cases.
If a nutritional deficiency is involved, correcting the underlying iron or B vitamin shortage is essential for lasting resolution. Dietary changes or supplements can address this, but it takes time for levels to rebuild.
Keeping It From Coming Back
Angular cheilitis has a reputation for recurring because people treat the surface infection without addressing what made them vulnerable in the first place. A few practical habits reduce the odds of another episode.
- Stop licking your lips. This is the single most important behavioral change. When the corners feel dry or tight, apply a barrier ointment instead.
- Keep the corners of your mouth dry. Gently pat the area dry after eating or drinking. Sleeping with your mouth open or drooling at night can also keep the skin saturated.
- Use a barrier ointment at night. A thin layer of petroleum jelly before bed protects the skin during the hours when you can’t consciously manage saliva.
- Check your dentures. If you wear dentures and notice cracking, have a dentist evaluate the fit. Adjusting vertical height can eliminate the skin fold that traps moisture.
- Address nutritional gaps. If your diet is low in iron, leafy greens, eggs, meat, or fortified cereals, the cracking is likely to return even after the infection clears.
Most cases clear within two weeks with proper treatment. If cracking persists beyond that, or if it keeps recurring despite these measures, the cause is likely something systemic, whether a nutritional deficiency, an immune issue, or a chronic yeast problem, that needs a closer look.