Smokers melanosis is seen with the naked eye as a brown to black pigmentation of the oral tissue i.e. the gums, cheeks or palate  as well as in larynx. It is most often seen in the lower labial gingiva of tobacco users. Most easily it is found in Caucasians, due to their lack of a genetically caused melanin pigmentation.The brown to black colour is melanin. In skin, melanin prevents harmful UV-light from reaching deeper, sensible parts of the tissue. If UV-light penetrates deep, some of the toxic substances due to the UV-light damage to the cells, are bound to melanin in the epithelial cells and travel with the ageing cells to the skin surface, where they are expelled from the tissue surface. In this way the melanocytes and keratinocytes together protect the tissue, with melanin serving as a toxic defence and cleaning agent. In the oral mucosa, where the ageing epithelial cells move faster to the surface compared to skin, a similar defence-mechanism seems to be present, cleaning the mucosa from different toxic chemicals penetrating the epithelium. Besides chemicals in tobacco  also antimalaria-drugs cause an oral pigmentation. Smokers melanosis is like the genetic melanin pigmentations, a defence-system in action. The microscope shows smokers melanosis to be characterized by a melanin hyperpigmentation of the lower part of the oral epithelium, similar to sun-tanned skin. The hyperpigmentation consists of melanin granules which have the shape and colour of "coffea beans".
Smokers melanosis is found in India, Italy, Japan, Nigeria, Sweden, Turkey, USA, and several other countries.Smokers melanosis is expected to be found also in other tissue surfaces exposed to tobacco and tobacco smoke, for instance lips and in skin of the fingers holding the cigarette. Future studies will also show if the use of tobacco exaggerates the pigmentation of skin. Gallery
See also
Melanosis coli
Peutz–Jeghers syndrome
Stomatitis nicotina
Smokeless tobacco keratosis

References
External links

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