What causes the cornerof mouth to crack?

There are several factors that can cause the corners of the mouth to crack, also known as angular cheilitis:

1. Nutritional deficiencies: A deficiency of certain vitamins and minerals, such as iron, zinc, riboflavin (vitamin B2), and vitamins B6, B9 (folate), and B12, can lead to angular cheilitis.

2. Dehydration: Not drinking enough water can cause the skin around the mouth to become dry and cracked.

3. Ill-fitting dentures: Dentures that don't fit properly can rub against the corners of the mouth, causing irritation and cracking.

4. Infections: Fungal infections (such as Candida) or bacterial infections (such as Staphylococcus aureus) can cause the corners of the mouth to crack and become inflamed.

5. Sun exposure: Prolonged exposure to the sun's UV rays without adequate protection can damage the skin around the mouth, making it more susceptible to cracking.

6. Contact dermatitis: Allergic reactions to certain substances, such as toothpaste, lipstick, or other cosmetics, can cause contact dermatitis, leading to inflammation and cracking of the skin around the mouth.

7. Smoking: Smoking can irritate the skin around the mouth and contribute to cracking.

8. Licking the lips: Frequent licking of the lips can dry out the skin and make it more prone to cracking.

9. Certain medical conditions: Some medical conditions, such as diabetes, Crohn's disease, anemia, and immune system disorders, can cause angular cheilitis.

If you experience persistent cracking at the corners of your mouth, it's important to see a healthcare professional for proper diagnosis and treatment. They can identify the underlying cause and recommend appropriate measures to manage the condition.