Skin on arms turning black

The sking on my brother's forearms is turning from white to black. I think he should see a doc but he won't. He is only outside briefly every day for smoke breaks, so I don't think it is overtanned. Any ideas?

[Bhupinder Kaur, MD]

Hello,
Without examination,confirmation of a diagnosis is tough,but it can be due to hyperpigmentation of the skin. This darkening occurs when an excess of melanin, the brown pigment that produces normal skin color, forms deposits in the skin.

Treatment involves hydroquinone, azelaic acid, corticosteroids, tretinoin cream and laser treatment. Pls discuss these options with your dermatologist before using them.

Hope it helps.Take care and pls do keep me posted on how you are doing or if you have any additional doubts.Kind regards.