<unk>  (STK) is a condition which develops on the oral mucosa (the lining of the mouth) in response to<unk><unk>  use. Generally it appears as a white patch, located at the point where the<unk>  is held in the mouth. The condition usually disappears once the<unk>  habit is stopped. It is associated with slightly increased risk of mouth cancer. There are many types of<unk><unk> . Chewing<unk>  is shredded, air-cured<unk>  with flavoring. Dipping<unk>  ("moist snuff") is air or fire-cured, finely cut<unk> . Dry snuff is ground or pulverised<unk>  leaves. In the Indian subcontinent, the Middle-East and South-East Asia,<unk>  may be combined in a quid or paan with other ingredients such as betel leaf, Areca nut and slaked lime. Use of Areca nut is associated with oral submucous fibrosis. An appearance termed Betel chewer's mucosa describes morsicatio buccarum with red-staining of mucosa due to betel quid ingredients. In Scandinavian countries, snus, a variant of dry snuff, is sometimes used. In the United States of America, the most common form of<unk><unk>  is dipping<unk> , although chewing<unk>  is sometimes used by outdoor workers and dry snuff is common among females in the Southern states. The overall prevalence of<unk><unk>  use in the USA is about 4.5%, but this is higher in Mid-Western and Southern states.
Smokeless tobacco keratosis
Hydrocarbon keratosis
Arsenical keratosis
PUVA keratosis
Actinic keratosis
Reactional keratosis
Occupational acne
Seborrheic keratosis