Disclaimers first. It’s not me, it’s my neighbor. I’m an RN, but this one has me a bit baffled, so I’m looking for a response from an MD - although layman responses are also welcome. He’s not my patient, but my neighbor, so HIPAA sholudn’t apply.
The guy has had lung problems for a while. His skin shows some marked melanization, especially in the forearms. I’m wondering why. I know he’s on corticosteroids for the COPD, but I wonder if the corticsteroids are the only factor. My question is this:
Can it be JUST the corticosteroids, are is there possibly something else contributing?
ETA: speculation is welcome.
Maybe he has small cell lung cancer (he does have COPD, after all) and it is secreting a pigmenting hormone which it is known to do (POMC/ACTH).
Or, maybe he’s already on chemo which can pigment the skln (e.g. busulfan and others).
Or, maybe he has hemochromatosis which darkens (“bronzes”) the skin. It is not that rare a condition, being the commonest single-gene disease among Caucasians, IIRC.
Well, you said to speculate!
ETA: his use of steroids seems irrelevant to me and, in particular, doesn’t explain his skin darkening
And I wanted it, Thank you 
I have experience with hemochromotisis, and it’s it not that. I also know that he has never had radiation treatments, so it’s not that, either.
However… small cell. I doubt it’s that, but it is a little disconcerting because it kinda sorta fits.
Anyway, Karl, yours is the exact type of speculation I want in this thread. Let’s brainstorm.