It starts as a tiny sting. Maybe you’re eating a salty chip or taking a big bite of a sandwich, and suddenly, the corner of your mouth feels like it’s being sliced by a papercut. You look in the mirror and see it: a deep, red, angry split. It’s annoying. It’s painful. Honestly, it’s kind of gross when it starts to crust over.
If you’ve been wondering why do my lips crack in the corners, you’ve probably already tried slathering on every lip balm in your nightstand only to find it does absolutely nothing. That’s because those stubborn cracks—medically known as angular cheilitis—usually aren't just "dry skin."
Dry lips happen when the air is cold. Angular cheilitis is a different beast entirely. It’s an inflammatory condition that targets the labial commissures (the fancy medical term for the corners of your mouth). While it looks like a simple chapped lip, it’s often an invitation for fungi or bacteria to move in and set up shop.
The Saliva Paradox: Why Licking Makes It Worse
Most people make the mistake of licking the area because it feels tight. Don’t do that. When you lick the corners of your mouth, you’re bathing the skin in digestive enzymes. As that saliva evaporates, it leaves the skin even drier than before.
It gets weirder.
Saliva is warm and moist. When it traps itself in those little folds at the edge of your lips, it creates a literal greenhouse for Candida albicans. That’s the same yeast responsible for thrush and diaper rash. This is why standard Chapstick doesn't work; you can't moisturize away a fungal overgrowth.
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Dr. Shari Marchbein, a board-certified dermatologist in New York, often points out that moisture becomes the enemy when it’s trapped. The skin macerates—it softens and breaks down—which allows the crack to deepen. If you see a white, filmy coating or a yellowish crust, you aren't just dealing with weather; you’re dealing with an infection.
It Might Be What You’re Missing (Nutrient Deficiencies)
Sometimes the "why" isn't about what you're doing to your face, but what's going on inside your body. Your skin is a massive gossip. It tells everyone when you’re low on vitamins.
If those cracks won't heal no matter what cream you use, check your blood work. Specifically, look at Vitamin B2 (Riboflavin), B12, and Iron.
- Iron Deficiency Anemia: This is a classic culprit. Without enough iron, your skin can't repair itself efficiently.
- The B-Complex Connection: B2 is crucial for mucous membrane health. When you're low, the corners of the mouth are often the first place to "blow out."
- Zinc: This mineral is the king of wound healing. A deficiency makes those cracks stay open for weeks instead of days.
Vegan and vegetarian diets can sometimes lead to these gaps if not supplemented correctly. Even if you eat meat, malabsorption issues like Celiac disease or Crohn's can prevent these nutrients from getting where they need to go. It’s not just about what you eat; it’s about what you actually absorb.
The Role of Your Dentist and Your Face Shape
This is the part nobody talks about. Your "bite" matters.
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As we age, or if we have certain dental alignments, the upper lip can slightly overhang the lower lip. This creates a permanent "pocket" or fold at the corners. Dentists call this a loss of vertical dimension. If you wear dentures that don't fit perfectly, or if you have a deep overbite, saliva naturally pools in those folds.
It’s like a tiny, wet gutter at the edge of your mouth.
I’ve seen people spend hundreds on luxury skincare when they actually just needed a better-fitting dental appliance or a tiny bit of filler to "lift" the corners and prevent the pooling. It sounds extreme, but if the anatomy of your face is funneling spit into a crack, no amount of Neosporin is going to fix the root cause.
Hidden Irritants in Your Routine
Sometimes we're the ones sabotaging ourselves. Check your toothpaste. Does it contain Sodium Lauryl Sulfate (SLS)?
SLS is a foaming agent. It’s in almost everything because people love bubbles. But for someone with sensitive skin or a tendency toward angular cheilitis, SLS is a massive irritant. It weakens the skin barrier. Switching to an SLS-free toothpaste (like certain Sensodyne versions or Verve) can sometimes stop the cycle of cracking in just a few days.
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Then there’s the "Cinnamon Factor." Cinnamic aldehyde, used for that spicy flavor in gum and toothpaste, is a common allergen. It can cause contact dermatitis that looks exactly like a cracked corner. If your mouth tingles or burns when you brush, your toothpaste is likely the villain in this story.
How to Get Rid of It for Good
You need a strategy. Not a random guess.
- Stop the Licking. Force yourself. Use a physical barrier if you have to.
- The "Triple Threat" Treatment. If it’s already cracked, many dermatologists suggest a tiny bit of over-the-counter hydrocortisone (for inflammation), an antifungal like Lotrimin (the stuff for athlete's foot—yes, really), and a thick barrier like Aquaphor. Mix a tiny dab and apply. Note: Don't use hydrocortisone for more than a few days without a doctor's okay.
- Barrier Ointments. Before you sleep, apply a heavy layer of white petrolatum (Vaseline) or CeraVe Healing Ointment to the corners. This acts as a raincoat, preventing saliva from soaking into the skin while you drool in your sleep.
- Dry It Out After Eating. After you eat or drink, gently pat the corners of your mouth dry with a clean napkin. Don't rub. Just dab.
- Check Your Meds. Some medications, like Isotretinoin (Accutane) for acne, are notorious for causing this. If you're on it, you need to be aggressive with the barrier creams from day one.
When to See a Doctor
If the crack is spreading, if it’s oozing yellow liquid (honey-colored crusting is a sign of a Staph infection called Impetigo), or if it’s been there for over a month, get professional help. A doctor can swab the area to see if it’s fungal or bacterial. They might prescribe a prescription-strength ointment like Mupirocin or a topical Nystatin.
Most of the time, though, it’s a lifestyle tweak. It’s fixing a vitamin gap. It’s stopping the "lick-dry-lick" cycle. It’s realizing that your mouth corners are sensitive little ecosystems that don't like being soggy.
Keep the area clean, keep it dry from saliva, and keep it protected with a thick barrier. That's the secret to never having to wince when you open your mouth for a burger again.
Next Steps for Relief
- Switch to an SLS-free toothpaste immediately to rule out contact irritation.
- Apply a thick layer of plain white petrolatum to the corners of your mouth before bed tonight to prevent nocturnal saliva pooling.
- Add a B-complex supplement or increase your intake of leafy greens and lean proteins if the cracks are a recurring seasonal issue.
- Consult a professional if the cracks show signs of infection, such as swelling, warmth, or golden-colored crusting.