I think you should go see an Endocrinologist or any Dr. and get some blood work. Ask them to check your hormone levels: ACTH and Cortisol.
I remember researching the same thing about 2 months ago online: "discoloration/ pigmentation on knuckles/ hands that had appeared overnight and wouldn't remove. I thought it was nothing, I was wrong. I saw my dr. and the first thing she said to me was ADDISON'S DISEASE. I was referred to an Endocrinologist and apparently I have Addison's Disease. I am being transfered to see a specialist at Cedars Sinai this month. Apparently brownish discoloration is the first prominent sign of Addison's. Please do NOT dismiss this. GO SEE YOUR DR. This could be serious, or it could be nothing- whatever you do, don't just ignore it. I have always been healthy my whole life. I live a totally health- conscious lifestyle and maintain a veggetarian diet. I don't know how I contracted this disease but I did. My point is, it can happen to anyone. See your doctor.
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