Q: What makes the corners of the mouth sore?
A: A number of deficiencies can cause soreness, reddening, superficial erosions and cracking of the skin at the corners of the mouth, where the mucus membrane of the lips meets the skin of the face. The medical terms for this condition include angular stomatitis or cheilosis.
B vitamin deficiencies, especially riboflavin (vitamin B2) but also niacin and pyridoxine (vitamin B8), can produce angular stomatitis that will generally heal or improve with adequate vitamin intake. Other possible causes of angular stomatitis are severe deficiencies or iron or vitamin B12, poorly fitting dentures and allergic reactions to lipstick or toothpaste. The problem may be made worse by excessive lip licking or local infections.
*Dr. Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine and associate dean for academic affairs at the school.