Hi. I have a big black patch on right and mid of my upper back. I acquired it 7-8 years ago. I first noticed it after I d been swimming for 2 weeks and assumed it was sun-burn. However it never went away. I ve seen dermatologists and they say that change of skin color is irreversible. That it s probably genetic. However nobody in my family has any issue like this. Recently a doc has diagnosed it as macular amyloidosis. She says it s due to use of loofah(excessive friction). She s prescribed ointments: xerina and kojivit. I have acne, sensitive skin, hairfall. My cycles are regular. Could this pigmentation be hormonal?