Hey - I'm interested in this histamine intolerance thing too. Looking back, I think I've teetered on the edge of it throughout my life. But taking estrogen seems to bring it on big time.
I tried a combined pill when I was 21yo (I'm now 44yo so that was some time ago!) and it brought on the same symptoms I'm battling now on HRT...
I get weird throbbing throughout my body - especially at night, sometimes before sleep, sometimes waking me up during the night - and I think that is associated with an episode of high blood pressure. (I'm v fit and active with normal BP usually and a low BMI.) I had to do a week of blood pressure monitoring (due to one high reading in the surgery as a result of this!) and the monitor said 'irregular pulse' about 50% of the time, so I believe I'm also getting palpitations of the fluttery jittery sort.
I also have a watery eye and a drippy nose - which gets worse after eating, resulting in a wet cough for about an hour or so afterwards.
And I have joint pain which has been thoroughly checked out with no other known causes. It has improved on the HRT but not resolved.
Apparently there's a correlation between histamine intolerance and hypermobility - I read that 80% of people with histamine intolerance are also hypermobile. And guess what... I'm hypermobile. I also have a history of mild endometriosis, which is also associated with it and obviously there's an estrogen connection there.
I am now trying a low histamine diet, to see if that helps. I'm only on day 3 so far.... I'm also taking vitamin C 3-4x a day, magnesium, and I've got quercetin and L-glutamine on order. The diet SUCKS.... I was waiting to see if I really think this is what I have before I get the DAO and the histamine friendly probiotics...