Why Is My Mouth Cracked at Corners? 7 Causes & Fixes

Cracked corners of the mouth — a condition doctors call angular cheilitis or perlèche — happen when saliva pools at the lip edges, creating a moist environment where yeast or bacteria thrive, often worsened by nutritional deficiencies, poorly fitting dentures, or chronic lip-licking.

The soreness, redness, and cracking you're seeing isn't just dry skin — it's an inflammatory response that won't heal on its own until you address the underlying cause. The good news: most cases clear up within one to three weeks once you identify what's triggering yours and treat it properly.

What Is Angular Cheilitis and Why Does It Make Your Mouth Sore at the Corners?

Angular cheilitis is inflammation specifically located at the commissures — the corners where your upper and lower lips meet — and it develops when persistent moisture breaks down the skin barrier, allowing opportunistic infections to take hold.

Unlike a simple cold sore (which is caused by the herpes simplex virus and typically appears on the lip itself), angular cheilitis targets only the corners of your mouth. The condition creates a frustrating cycle: the cracks hurt when you open your mouth wide, so you avoid stretching your lips, but the moisture keeps accumulating in those folds, preventing healing.

The skin at your mouth corners is uniquely vulnerable. It's thinner than the skin on other parts of your face, lacks oil glands, and constantly moves when you eat, talk, and yawn. When saliva repeatedly wets this area and then evaporates, it strips away natural oils and creates microscopic fissures that become entry points for Candida (yeast) or Staphylococcus bacteria.

"Angular cheilitis is most commonly caused by a mixed infection of Candida albicans and Staphylococcus aureus, though it can also occur due to nutritional deficiencies or mechanical factors." — American Academy of Dermatology

7 Causes of Cracked, Sore Mouth Corners in 2026

Understanding exactly why your mouth is cracking at the corners requires looking at both local irritants (like drool and dentures) and systemic factors (like vitamin deficiencies and immune status) that compromise your skin's ability to heal.

Does Saliva Buildup Cause Cracked Lip Corners?

Yes — and it's the most common trigger. When saliva collects in the creases at the corners of your mouth, it softens and macerates the skin. Once the saliva evaporates, the skin dries out and cracks. People who drool during sleep, have a habit of licking their lips, or produce excess saliva are especially prone.

The saliva itself contains digestive enzymes designed to break down food, and these enzymes also break down the delicate skin at your mouth corners when given prolonged contact.

Can Vitamin Deficiencies Make Your Mouth Sore in the Corners?

Absolutely. Deficiencies in B vitamins — particularly B2 (riboflavin), B3 (niacin), B6 (pyridoxine), and B12 — are strongly associated with angular cheilitis. Iron deficiency anemia and zinc deficiency also compromise skin integrity and immune function, making the corners of your mouth more susceptible to cracking and infection.

If your cracked corners keep coming back despite topical treatment, a blood test to check your nutritional status is worth discussing with your doctor.

Do Dentures or Braces Cause Angular Cheilitis?

Poorly fitting dentures are one of the most common causes in older adults. When dentures don't fit properly — whether they're too old, were made incorrectly, or your jaw has changed shape over time — they alter your bite and create deeper folds at the mouth corners where moisture accumulates.

Orthodontic appliances, including braces and retainers, can cause similar issues by changing how your lips rest when your mouth is closed or by increasing saliva production.

Can Yeast or Bacterial Infections Cause Mouth Corner Cracking?

In most cases, yes — infection is present. Candida albicans, the same yeast that causes thrush and vaginal yeast infections, is found in approximately 93% of angular cheilitis cases. Staphylococcus aureus bacteria is present in about 60% of cases, and many people have both simultaneously.

These organisms normally live on your skin and in your mouth without causing problems. They only become pathogenic when the skin barrier is already compromised — which is why treating the infection alone often isn't enough if you don't also address what's allowing it to flourish.

"The organisms that cause angular cheilitis are usually part of normal flora and only become problematic when local or systemic factors create conditions favorable for their overgrowth." — National Institutes of Health

Does Diabetes Increase Your Risk?

Yes. People with diabetes are significantly more prone to angular cheilitis for several reasons: elevated blood sugar creates a favorable environment for yeast growth, diabetes often causes dry mouth, and the condition impairs wound healing. If you're experiencing recurrent cracked mouth corners and haven't been tested for diabetes recently, it's worth mentioning to your healthcare provider.

Also Read: Why Is My Body Warm but Feet Are Cold? 8 Causes & Fixes

Can Allergies or Skin Conditions Trigger It?

Contact allergies to lip products, toothpaste ingredients, or dental materials can cause or worsen cracking at the mouth corners. Common culprits include:

• Fragrances and flavoring agents in lip balms
• Sodium lauryl sulfate in toothpaste
• Nickel in orthodontic wires
• Cinnamon and peppermint flavorings

Underlying skin conditions like eczema (atopic dermatitis) and seborrheic dermatitis also predispose you to angular cheilitis by weakening the skin barrier.

Does Cold, Dry Weather Make Mouth Cracking Worse?

Winter weather creates a perfect storm for angular cheilitis. Cold, dry air dehydrates your skin while indoor heating strips even more moisture. You lick your lips more frequently in an attempt to moisten them, which paradoxically makes the problem worse as saliva evaporates and pulls water from the already-dry skin.

How to Treat Cracked Corners of the Mouth

Treatment depends on identifying the cause, but most cases respond well to a combination of antifungal medication for the yeast component, keeping the area dry, and applying a barrier ointment to protect healing skin.

Topical Antifungal Treatment

Over-the-counter antifungal creams containing clotrimazole, miconazole, or ketoconazole are typically the first line of treatment. Apply a thin layer to the affected corners two to three times daily for one to two weeks. If the infection is severe or doesn't respond, your doctor may prescribe a stronger antifungal like nystatin.

Antibacterial Treatment When Needed

If your doctor suspects a bacterial component — common signs include yellow crusting, pus, or failure to respond to antifungals alone — they may prescribe a topical antibiotic like mupirocin. Some cases require combination therapy addressing both yeast and bacteria.

Creating a Moisture Barrier

Once infection is controlled, applying a thick barrier ointment like petroleum jelly or zinc oxide paste helps protect the healing skin from saliva. Apply after meals and before bed. Avoid licking the area — if you catch yourself doing it, that's your cue to reapply the barrier.

Addressing Underlying Causes

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When to See a Doctor About Cracked Mouth Corners

See a healthcare provider if your symptoms don't improve after two weeks of home treatment, if the cracking spreads beyond the corners, or if you develop fever, significant swelling, or signs of infection spreading.

You should also seek medical attention if:

• The cracks are deep, bleeding, or extremely painful
• You have diabetes or a weakened immune system
• The condition keeps recurring despite treatment
• You notice white patches inside your mouth (which could indicate oral thrush)
• You're losing weight unintentionally or have other unexplained symptoms

A doctor can take a swab to identify exactly which organisms are present and prescribe targeted treatment. They can also order blood tests to check for vitamin deficiencies, anemia, or diabetes if these are suspected.

How to Prevent Mouth Corners From Cracking Again

Prevention focuses on keeping the mouth corners dry, maintaining good nutrition, and addressing any dental or medical issues that predispose you to the condition.

• Avoid licking your lips, especially the corners
• Apply barrier ointment (petroleum jelly or lanolin) before bed and after meals
• Stay hydrated — drink enough water throughout the day
• Use a humidifier in winter to combat dry indoor air
• Choose fragrance-free, hypoallergenic lip products
• Get dental work checked — ensure dentures fit properly
• Eat a balanced diet with adequate B vitamins, iron, and zinc
• If you use a CPAP machine, ensure proper mask fit to prevent air leaks

In Short

Cracked, sore mouth corners — angular cheilitis — develop when moisture weakens the skin at your lip edges, allowing yeast and bacteria to cause infection. Common triggers include lip-licking, ill-fitting dentures, vitamin deficiencies, and dry winter air. Most cases heal within one to three weeks with antifungal treatment and barrier ointments, but persistent or recurring cracks warrant a doctor visit to check for underlying conditions like diabetes or nutritional deficiencies.

What You Also May Want To Know

Why is my mouth sore in the corners but not cracked?

Soreness without visible cracking often indicates early-stage angular cheilitis before the skin has fully broken down. You may notice redness, tenderness, or a burning sensation before cracks appear. This is actually the ideal time to treat — applying antifungal cream and barrier ointment now may prevent the condition from progressing to visible cracks.

Why is my mouth cracking in the corners only on one side?

One-sided angular cheilitis usually points to a local rather than systemic cause. Common culprits include sleeping on that side (which causes more drooling on one corner), a dental issue on that side of your mouth, or a habit like holding a pen or musical instrument that wets only one corner. Check for any asymmetric factors in your daily routine.

Can angular cheilitis spread to other people?

Angular cheilitis itself isn't contagious in the usual sense. The yeast and bacteria that cause it are normal residents on everyone's skin and mouth. However, kissing someone while you have active cracked corners could theoretically transfer organisms, and you shouldn't share lip products, utensils, or towels while symptomatic — more to protect your own healing skin than to prevent spread.

How long does angular cheilitis take to heal completely?

With appropriate treatment, most cases heal within one to three weeks. However, if the underlying cause isn't addressed — like a vitamin deficiency or poorly fitting dentures — the condition will likely return. Stubborn cases that persist beyond three weeks of treatment need medical evaluation to identify what's preventing healing.

Does putting Vaseline on cracked mouth corners help?

Petroleum jelly (Vaseline) is helpful as a protective barrier but won't treat the underlying infection. Use it alongside antifungal treatment, not instead of it. Apply petroleum jelly after your antifungal cream has absorbed to seal in moisture and protect the healing skin from saliva. On its own, Vaseline may actually trap moisture and organisms against the skin, potentially worsening the problem.

Reviewed and Updated on June 1, 2026 by George Wright