What causes cracked corners of the mouth?

Possible causes of cracked mouth corners may include the following: 1. Malnutrition: Long-term picky eating or an unbalanced diet, especially deficiencies in key nutrients such as vitamins B2 and B6, may lead to dry skin and subsequently cause angular cheilitis, manifesting as cracked or sore mouth corners. 2. Poor lifestyle habits: Frequently licking the corners of the mouth with the tongue or picking at them with the hands may cause local tissue damage and result in erosion. Additionally, in dry air conditions, saliva evaporates quickly; thus, licking the lips can actually worsen dryness and cracking at the mouth corners. 3. Infection: Infections caused by pathogenic microorganisms such as bacteria or viruses may also lead to angular cheilitis. For example, herpes virus infection often presents with redness, swelling, and fissures at the corners of the mouth, gradually progressing to erosion. 4. Allergic reactions: Contact with allergens such as lipsticks or facial creams may trigger contact angular cheilitis, characterized by symptoms including redness, itching, and erosion. 5. Other factors: Conditions such as malocclusion, or keeping the mouth open for prolonged periods during dental examinations or treatments, may also predispose individuals to angular cheilitis.