I don't believe it is a fellowship, but you just do a derm residency minus the prelim year. So, you just do 3 more years. There is a 4 year combined proram at UT Galveston and Penn, but only 2 spots exist currenty.
pediatric dermatology is a 2 year pediatric derm fellowship after DERMATOLOGY residency. the fellowship is shortened to one year if you did a pediatric preliminary year or already completed a peds residency. i don't know anything about the combined programs.