My new ME/CFS doctor suspects I have MCAS and wants me to start meds for it. I was already taking Claritin in the AM but added Allegra @ night and Zantac 150mg 2x day. I've been following this protocol for ~4 days now and I'm sneezing, itchy, have brain fog, chest congestion and post nasal drip. Except for the itching, I wasn't feeling this way before I started these meds. WTH? Has anyone else experienced this when starting MCAS meds?