<unk>  has been reported to have occurred with<unk> -containing ointment causing papules on the penis of a patient.<unk>  screws used for orthopedic procedures, if they come near the skin, can also causes cutaneous blue-black hyperpigmentation.
Titanium metallic discoloration
Iron metallic discoloration
Hemosiderin hyperpigmentation
Harlequin color change
Antimicrobial properties of copper
Pica 
Crazy paving 
Dark skin