Stomatitis is inflammation of the mouth and lips. It refers to any inflammatory process affecting the mucous membranes of the mouth and lips, with or without oral ulceration.In its widest meaning, stomatitis can have a multitude of different causes and appearances. Common causes include infections, nutritional deficiencies, allergic reactions, radiotherapy, and many others. When inflammation of the gums and the mouth generally presents itself, sometimes the term gingivostomatitis is used, though this is also sometimes used as a synonym for herpetic gingivostomatitis. The term is derived from the Greek stoma (στόμα), meaning "mouth", and the suffix -itis (-ῖτις), meaning "inflammation". Causes
Nutritional deficiency
Malnutrition (improper dietary intake) or malabsorption (poor absorption of nutrients into the body) can lead to nutritional deficiency states, several of which can lead to stomatitis. For example, deficiencies of iron, vitamin B2 (riboflavin),: 490  vitamin B3 (niacin), vitamin B6 (pyridoxine), vitamin B9 (folic acid) or vitamin B12 (cobalamine) may all manifest as stomatitis. Iron is necessary for the upregulation of transcriptional elements for cell replication and repair. Lack of iron can cause genetic downregulation of these elements, leading to ineffective repair and regeneration of epithelial cells, especially in the mouth and lips. Many disorders which cause malabsorption can cause deficiencies, which in turn causes stomatitis. Examples include tropical sprue. : 49

Aphthous stomatitis
Aphthous stomatitis (canker sores) is the recurrent appearance of mouth ulcers in otherwise healthy individuals. The cause is not completely understood, but it is thought that the condition represents a T cell mediated immune response which is triggered by a variety of factors.
Apart from not being restricted to the tongue, migratory stomatitis is an identical condition in every regard to geographic tongue. Another synonym for geographic tongue which uses the term stomatitis is "stomatitis areata migrans". Herpetic gingivostomatitis
This is inflammation of the mouth caused by herpes simplex virus. Irradiation and chemotherapy
Stomatitis may also be caused by chemotherapy, or radiation therapy of the oropharyngeal area. The term mucositis is sometimes used synonymously with stomatitis, however the former usually refers to mucosal reactions to radiotherapy or chemotherapy, and may occur anywhere in the gastrointestinal tract and not just in the mouth. Necrotizing ulcerative gingivostomatitis
The term necrotizing ulcerative gingivostomatitis is sometimes used as a synonym of the necrotizing periodontal disease more commonly termed necrotizing ulcerative gingivitis, or a more severe form (also termed necrotizing stomatitis). The term necrotizing gingivostomatitis is also sometimes used. Stomatitis nicotina
Also called smokers palatal keratosis,: 176  this condition may occur in smokers, especially pipe smokers. The palate appears dry and cracked, and white from keratosis. The minor salivary glands appear as small, red and swollen bumps. It is not a premalignant condition, and the appearance reverses if the smoking is stopped. : 176

Chronic ulcerative stomatitis
Chronic ulcerative stomatitis is a condition with specific immunopathologic features, which was first described in 1990. It is characterized by erosions and ulcerations which relapse and remit. Lesions are located on the buccal mucosa (inside of the cheeks) or on the gingiva (gums). The condition resembles oral lichen planus when biopsied.