“… 30 Ironically, in the case of immediate type B (IgE-mediated) adverse reactions (eg, urticaria or anaphylaxis), trimethoprim is more often the culprit. 31 , 32 , 33 , 34 , 35 Incorrect allergy labeling of patients who have had an allergic reaction to TMP-SMX as “sulfur allergic” may result in them receiving trimethoprim which could be dangerous.…”