Cracks in the corners of the mouth, also known as angular cheilitis, can be caused by several factors, including:

1.

Fungal infection: Candida albicans, a type of yeast, can thrive in the warm, moist environment of the mouth corners, leading to inflammation and cracking.

2.

Bacterial infection: Staphylococcus aureus or other bacteria can cause infection and irritation in the corners of the mouth.

3.

Nutritional deficiencies: Deficiencies in B vitamins (especially B2, B3, and B12), iron, or zinc can weaken the skin and mucous membranes, making them more susceptible to cracking.

4.

Excessive saliva accumulation: Saliva pooling at the corners of the mouth, often due to poorly fitting dentures or habitual lip licking, can contribute to irritation and cracking.

5.

Dryness: Environmental factors like cold weather or dry air, as well as dehydration, can lead to dry, cracked skin at the corners of the mouth.

6.

Allergic reactions: Some individuals may have allergic reactions to certain foods, oral hygiene products, or lip balms, leading to irritation and cracking.

7.

Medical conditions: Conditions such as oral thrush, inflammatory bowel disease, or autoimmune disorders can increase the risk of angular cheilitis.

Treatment typically involves addressing the underlying cause, such as antifungal or antibacterial medications for infections, nutritional supplements for deficiencies, and proper oral hygiene practices. If the condition persists or worsens, it’s advisable to consult a healthcare professional for further evaluation and treatment.