I've had "vulvar dermatitis" x's 2 yr now effectively tx w/ clobetasol. Now having same itch on both arm pits & anus- no rash bumps or redness. Ideas?

Hard to tell. It may be some idiopathic (unknown cause) pruritis (itchiness), however, i would get checked for diabetes and also i would get a complete blood count checked. I've seen a few cases of blood related problems that were manifested by pruritis (itching) well before other symptoms appeared.
Consider. This may be fungal issue. Steroids can hide this, then flare after treatment has stopped. However, since going on so long this needs evaluation to rule out more serious issues, .