What Causes Blotches Along The Shaft Of Penis?

I have red blotches or dry sky on my penis and up the shaft (not the head) it was diagnosed as Thrush but the Thrush cream did not treat it. I have since used Hydrocortisone cream which has helped but the blotches will reoccur if Hydrocortisone is not used regular. Will this be a problem for me all my life or is there something else I could use to get rid of it permanently. it can sometimes be itchy and I suffered from Eczema as a youngster