Hiya
I have massive mast cell and histamine issues and did pre covid, but then I got covid, and I feel your pain. I see Dr Tina Peers, there's some info on her website about histamine if you google her (Louise Newsom also has some info in her fact sheets section).
Oestrogen is histamine and mast cell aggravating. You could try something like 120mg fexofenadine twice a day (available OTC) and or famotidine (H2 antihistamine, it's OTC in the USA as Pepcid, you can get it on Ebay or buy it OTC in Greece or other places in Europe) and see if that helps. Famotidine is also being trialled during covid infection now (if you google that), as it seems to prevent a mild infection worsening, there's some interesting info about it.
I'm struggling post covid, but pre covid I could not tolerate E without first steadying the histamine. Low histamine diet also helps, I use the Swiss List of foods.
x