There are 4 possible mechanisms to how this change may occur: # Accumulation of melanin, the skin pigment # Accumulation of<unk>  or one of its products under any layer of the skin (usually the dermis or epidermis) # Accumulation of iron throughout the dermis from<unk><unk>  post-inflammatory changes # The synthesis of special pigments, under direct influence of the<unk>
Drug-induced pigmentation
Chemotherapy-induced hyperpigmentation
Neurocutaneous melanosis
Phakomatosis pigmentokeratotica
Melanocytic nevus
Riehl melanosis
Smoker's melanosis
Congenital melanocytic nevus