Harlem [Dream Deffered]

This poem has lots of simile in it...

Does it dry up
like a raisin in the sun?
Or fester like a sore— (shriveling up like a raisin)
Does it stink like rotten meat?
Or crust and sugar over—
like a syrupy sweet?  (compares the dream to food)

Maybe it just sags
like a heavy load.

The them  of the poem to me seems to be frustration. And its not hard to believe that with the Era it was written in. 
It makes me wonder what his dreams were??