Re: Candida/Leaky Gut connection to histamine?
Candidiasis is essentially first and foremost an immune system weakness to pathologic fungi/yeasts. Hence, any rash should be assumed to be topical fungus unless proven otherwise. HOWEVER, since irritation and fungus appear to potentiate each other, the best thing to do for a skin irritation that just popped up is a three-pronged attack of a topical antifungal (ketaconazole, terbinafine, or even nystatin creams), a standard girlie day cream (those work wonders), and a topical STEROID.
Yep, steroids. Topicals used rarely and sparingly are harmless, since they aren't absorbed systemically and thus don't mess with your immune system. Used heavily, they can erode skin, but that's for years of daily use... However, a day or two of steroid application can nip irritation in the bud and stop it in its tracks, where otherwise it might take ages to clear up.
...as to histamine, it is not the cause, but the EFFECT. It's a reaction to fungal toxins.