What Causes Cracks at the Corners of the Mouth?

Cracked corners of the mouth (angular cheilitis) are a common issue experienced by many people. While dry weather is often blamed for this condition, other everyday habits can also contribute to it. So, what causes cracked mouth corners? Let’s explore the possible reasons below.

What Causes Cracked Mouth Corners?

1. Dehydration

Dry weather and insufficient bodily hydration can lead to cracking at the corners of the mouth, often accompanied by accumulation of dead skin around the mouth or at the oral commissures.

2. Vitamin Deficiency

Cracks at the corners of the mouth—especially when accompanied by white discharge near the oral commissures—may indicate a deficiency in certain vitamins. In particular, inadequate intake of vitamin B2 (riboflavin) or vitamin A—often due to insufficient consumption of fresh vegetables—can result in dry, cracked mouth corners.

3. Cheilitis

Frequent cracking at the mouth corners may stem from either vitamin B2 deficiency or digestive dysfunction. Alternatively, it could signal chronic cheilitis. This condition commonly affects young adults and is frequently triggered by unhealthy habits such as lip-licking or lip-biting. These behaviors can worsen pain, cause bleeding and infection at the corners of the mouth, delay wound healing, and lead to recurrent episodes—creating a vicious cycle. If left untreated for several days, acute cheilitis may progress into chronic cheilitis.

4. Oral Diseases

Oral conditions such as aphthous ulcers (canker sores) may also cause cracking at the mouth corners. Therefore, maintaining good oral hygiene is essential.

The above outlines the primary causes of cracked mouth corners. Individuals with sensitivities or allergies to cosmetics or sunlight, those prone to emotional fluctuations and internal “heat” (a traditional Chinese medicine concept associated with inflammation), and people who regularly consume spicy foods are also at increased risk. If cracks persist, form scabs, and fail to heal over an extended period, prompt medical evaluation and treatment are recommended. We hope this information is helpful to you.