Any condition of unusual deposits of black pigment in different parts of the body is known as melanosis.
This condition is a form of hyperpigmentation that is associated with increased melanin. Hyperpigmentation, which is manifested as darkening on the skin, can be caused by sun damage, inflammation, or skin injuries. There are different types of melanosis such as Melanism, ocular melanosis, smoker's melanosis, oral melanosis, Riehl melanosis.