As long as they're strong letters, it doesn't matter. They don't have to be all 4 derm letters. I had 3 Derm letters and 1 from Peds and matched.

I had 1 derm and 2 Medicine letters and they were great

3 derm (rural, dermpath, and academic) IM I matched last year

4 strong derm letters is the best case, mostly because connections help (I did residency with your letter writer, oh your letter writer was my attending when i was a resident, etc). I personally had 3 derm and 1 IM. My IM letter was really strong but no one ever mentioned it. In short, 4 really strong derm letters are the best, but a really strong non-IM letter is better than a lukewarm derm letter

Prolly a silly question but if a program asks for at least 3 letters- is it better to give 3 or 4 letters?

So I sent 4 LORs to all derm programs. It wasn't a big deal at all. It wasn't some type of trick to see if you were following directions if you'd only send 3, if they were to ask for 3 on the website. I think they all know you're sending apps electronically en masse so you're just clicking. Essentially on the other end, a residency program coordinator prints all this stuff out from the ERAS portal (App, MSPE, Personal Statement, LORs, etc.) for individual derm faculty to review. It's a lot of paper so they don't have time for nitpicking.

*For cosigned letters (a derm attending wrote it and it was cosigned by the chair) how do you fill these out for ERAS?