Guys, I think there are some important things that needs to be said here.
First, histamine IS a trigger for CH, and in many cases foods high in histamine also contain other triggering agents. This includes all aged, preserved, smoked, cured, pickled and fermented foods and drinks, that are also rich in tyramine.
Of course, this does not necessarily mean that a law histamine diet will make a noticeable change for many, but some may benefit. It won't help too many people because (a) histamine is only one common trigger out of many and (b) food is hardly the only source of histamine. Histamine is not only consumed but mostly manufactured in the body, especially during CH attacks.
Benadryl is beneficial for some people as a short-term preventative, because it inhibits H1 receptors in the brain. It's also useful to prevent Vitamin D depletion due to allergic reaction, which is crucial for the D3 regimen in some people.
So, not a cure and not for everybody, but Benadryl and low histamine diet may help some people.