overall a decent read. i do wonder if the author is aware mcas is not solely limited to chemical sensitivity, mast cells don’t discriminate between natural and artificial and the continued emphasis solely on toxin induced mast cell response can easier be read either as a hyper narrow focus due to the topic, or unfamiliarity/dismissal of mundane mcas causes. i’m not inclined to hold it against the author enough to dock points from my rating, but as someone whose mcas will ignore household chemicals but pull the fire alarm when faced with everyday copper, the omission is curious at minimum.