Your lips are made of skin that is soft and delicate. As a result, they can easily crack and split under certain conditions.

Although it can be painful and bleed, splitting doesn’t usually indicate a serious problem. Nonetheless, this condition can be bothersome, so it’s important to understand the cause of a split lip and ways to promote healing.

Causes of a split lip

Since a split lip can develop gradually, it may be difficult to pinpoint the exact cause. Understanding possible reasons can help you determine the best way to treat and prevent future splitting. Common causes include:

1. Chapped lips

Chapped lips is a form of lip inflammation trigged by skin irritation. Lips can become extremely dry and cracked any time of the year due to environmental factors such as cold weather, dry air, and wind exposure. Angular cheilitis specifically affects the corners of the mouth and can be due to environmental factors and a host of other causes.

Lips are particularly prone to flaking, peeling, splitting, and dryness since they don’t have the same protection from the elements as other skin. They’re also unable to produce their own moisture.

2. Sun damage

We use sunscreen to protect our bodies from the sun’s harmful UV rays. It’s important to protect your lips as well. Exposing unprotected lips to the sun can lead to inflammation.

Long-term exposure causes the lips to become stiff and dry, resulting in cracking or splitting.

3. Lip injury

A split lip can also occur after an injury. This includes a blow to the mouth, falling and hitting your mouth, biting your lip, or getting a paper cut.

In addition to a split lip, you may also experience bleeding and swelling.

4. Dehydration

Sometimes, a split lip is due to an underlying medical problem like dehydration. This is when your body doesn’t have a sufficient amount of fluid. You can become dehydrated from vomiting, diarrhea, intense sweating, and illness. There’s also the risk of dehydration if you don’t take in enough fluids. Dehydration makes it harder for your body to function properly. Severe dehydration can be life-threatening.

5. Vitamin and mineral deficiency

Vitamin B includes thiamine, niacin, biotin, folic acid, and riboflavin. These are water-soluble vitamins that play a role in metabolism, provide energy, and help your body fight diseases.

Since vitamin B also contributes to healthy skin, a deficiency can cause a variety of skin problems such as acne, split lips, dryness, and rashes. Low levels of zinc and iron can also lead to split lips, especially at the corners of the mouth.

6. Allergy

An allergic reaction to lipstick, toothpaste, moisturizers, and any item applied to or around your lips could cause a split lip. Other symptoms could include severe dryness, irritation and itching, or an acute eczema-like rash on the lips.

If you develop lip problems after using a new lip product, discontinue use and see if your condition improves. This condition can become ongoing if the problem causing the allergy is not identified and corrected.

When to see a doctor

Many cases of split lips are treatable with home remedies. This is particularly true of cases caused by chapping or dryness, often as a result of extremes in heat, cold, or wind. But since a split lip could also indicate an underlying medical problem, see a doctor if your lip worsens or if other symptoms develop.

Since inadequate fluid intake can be a cause, look for other symptoms that include:

  • extreme thirst
  • infrequent urination
  • dark-colored urine
  • dizziness

If your body doesn’t receive adequate fluid and electrolytes, this could lead to kidney damage, seizures, and low oxygen levels. Identifying the source of dehydration is an important step in treatment.

Similarly, having a split lip with memory problems, numbness or tingling, or fatigue could indicate a vitamin B deficiency or other serious nutritional problem.

You should also see a doctor if the pain, bleeding, or redness associated with your split lip worsens.

Any sign of infection accompanying a split lip such as fever, shortness of breath, ongoing nausea, vomiting, or diarrhea also requires medical attention.

How to treat a split lip

Treatment for a split lip includes:

Protect your lips

Exposure to cold air, dry air, wind, and the sun can dry out lips and cause cracking and splitting. Apply lip balm or petroleum jelly to your lips before heading outdoors. This provides a protective barrier to keep your lips moisturized. Look for medicated lip balm and lip balm with SPF to prevent burns.

Don’t lick your lips

Constantly licking your lips can cause drying and further cracking and splitting.

Increase your fluid intake to keep your body and lips hydrated

Staying well-hydrated with caffeine-free fluids is important. Limiting alcohol is key since it can act as a diuretic and promote excessive urination. Excessive alcohol use can cause vomiting and diarrhea, which can worsen dehydration.

Apply a cold compress to bleeding lips

This can stop bleeding and reduce swelling, especially when due to injury.

If you notice crusting or opens sores around your lips, see your doctor. This can be a sign of a bacterial or viral infection. Your doctor may prescribe medication to treat the underlying problem. Blood or urine tests may be required if the cause of the problem is not clear.

If you’re dehydrated, you may need to receive fluids intravenously depending on the severity of your condition. In the case of a nutritional deficiency, your doctor may recommend dietary changes, supplements, or other treatments.

What is the outlook for a split lip?

In most cases, you should be able to treat your lip and avoid future cracking with home remedies. However, don’t ignore a split lip that’s accompanied by other symptoms, or a lip that doesn’t heal. See your doctor as soon as possible to determine the underlying cause.