Intense Anal/Groin Itch

I have been dealing with an anal itch for about 10 years.  I havent told anyone about it and got by using Lanacort from time to time for temporary relief.  I can't seem to find Lanacort anymore at stores so i have gone other routes by using Lanacane, Gold Bond, and other OTC anti-itch products.  It seems though that nothing else works sufficiently to treat it even temporarily.  I have a mildly uncomfortable itch on my inner thighs and working down under the scrotum towards the anus it gets progressivley worse.  Around the anus itself the itch is intense and can get to a point where it prevents me from being productive in any way.  The anus is red but im not sure if thats from the rash or from scratching so much. Around the groin it looks pretty normal as it does also under the scrotum yet both areas persistently itch.  On a side note, I have to use Head and SHoulders shampoo every day if i dont want dandruff and an itchy scalp.   Any thoughts?