And then also Blood Brain Barrier permeability, and presumably that can account for the brain fog. But as usual, nothing would be that simple, and so from PNAS: http://www.pnas.org/content/107/44/18967.abstract with the "unexpected" and "contrary to prevailing opinion" results that histamine actually decreased (not increased) BBB permeability in KO mice. Also, bad news: tryptase seems to account for joint degradation in rheumatoid arthritis (1:33 news report): So mast cells' tryptase and other possible proteinases might very well explain why my joints get loose when I'm sick. Inhibiting histamine then won't necessarily help with that, so MC stabilizers seem a better tactic. I'll have to look into the drugs you name, though lack of insurance inhibits that. The two natural MC stabilizers that I'm aware of are quercetin and then something found in olive oil.