Posted 9/12/2021 3:41 PM (GMT -6)
Claritin might ease symptoms of MCAS especially if they are respiratory, and some do find it helpful. If you can't avoid triggers, though, it might not make much of a difference. (Like if you took a Claritin, then you might feel a bit better, but still would not react well to kombucha.) Each mast cell stabilizer might affect you differently, so it's best to try a few types until you find a good combination for you.
Other antihistamines and mast cell stabilizers to try, instead or in addition:
Low-histamine diet (for some, this is crucial, myself included. No herbs or meds are going to help if I am jacking up my histamine levels from within!)
H1 blockers (like Claritin)
H2 blockers (like Pepsid)
Stinging nettles (great as a tea)
cromolyn sodium (Rx)
And avoiding triggers until your flare has passed. Limbic system retraining programs like DNRS and Gupta also can rewire the parts of your brain that are activating mast cells inappropriately.
In case it's helpful, here are some triggers to keep in mind:
Heat, sweating, saunas
Allergens (pollen, poison ivy, etc.)
Environmental toxins (cleaning products, body products, etc.)
Herxing, injuries, viruses
High-histamine supplements (some probiotic strains, lion's mane mushroom, etc.)
High-histamine foods (alcohol, anything fermented, anything aged, leftovers, citrus, tomato, vinegar, etc.)
Some people can tolerate some triggers sometimes, but then reach a tipping point. Like you might be fine most of the year, but have MCAS symptoms when it's ragweed season and hot, for example. For a while I was tolerating some fermented foods well in moderation, after not eating them for years, but then I had an unrelated intestinal disturbance that caused irritation in my system and led me to react again. Usually a low-histamine diet, quercetin, and curcumin are enough to keep me feeling fine with regard to MCAS, but triggers added up until it flared, and I needed a few doses of cromolyn sodium to calm the symptoms.
I was diagnosed clinically (by someone with experience treating MCAS, based on signs and symptoms). During flares I have had elevated eosinophils show up on CBCs, but my LLMD felt like further testing wasn't warranted because my symptoms are so directly related to eating high-histamine foods, and therefore pretty obvious. There's some controversy about the tryptase and histamine tests for MCAS because they require precise triggering and timing to come out positive.