Interesting side note. The "sulfa" abx I took that "caused" my colitis: sulfamethoxazole and trimethoprim could have indeed caused a massive mast cell cascade that flipped the switch on: "sulfonamide antimicrobials interact with the MRGPRX2 receptor and trigger a mast cell response."
If anyone else here had a sudden onset after taking a sulfa drug, holler :-0
Ref article: "Typical antimicrobials induce mast cell degranulation and anaphylactoid reactions via MRGPRX2 and its murine homologue MRGPRB2"