Cheilosis, also known as angular cheilitis, is a condition characterized by inflammation and cracking at the corners of the mouth. It can be caused by various factors, including nutritional deficiencies (such as vitamin B2, B3, or iron), fungal or bacterial infections, and excessive moisture or irritation. Symptoms typically include redness, soreness, and sometimes bleeding in the affected areas. Treatment often involves addressing the underlying cause, maintaining proper oral hygiene, and using topical ointments or creams to promote healing.