Updated February 23, 2021
Mucositis is inflammation of the mucosal tissues of mouth and esophagus, usually after radiotherapy for cancer. It can also happen after chemotherapy. This is because anti-cancer therapies target rapidly or continuously dividing cells. This is why the GI tract, the hair and skin, and blood cells are often affected during these therapies.
It can also reflect infection with yeast, herpes and other organisms, sometimes at a stealth level. Allergy to food and drink can also cause chronic mucosal inflammation. When it happens in the small intestine it is usually called leaky gu and in the colon colitis.