The term, ‘hyperpigmentation’, explains the presence of an increased amount of melanin in the skin by two main mechanisms. Certain hyperpigmentation conditions are caused due to increased melanin production with a normal number of melanocytes in the skin (melanotic hyperpigmentation). But there are certain conditions in which the number of melanocytes is increased (melanocytotic hyperpigmentation), leading to an increased melanin production.

Usually, the basal layer (stratum basale) of the epidermis contains melanocytes and an increased activity of these cells lead to increased melanin production, which will cause epidermal hyperpigmentation. This is the most commonly found form of hyperpigmentation disorders. In dermal hyperpigmentation, it is a transferring of epidermally produced melanin to the dermal layer.  Sometimes, a combination of both these mechanisms of melanin production may take place, resulting in mixed hyperpigmentation.