BACITRACIN ANAPHYLAXIS WITH MUCOSAL BUT NOT CUTANEOUS EXPOSURE

Abstract

<h3>Introduction</h3> Evaluation of anaphylaxis involves obtaining a detailed history of medications and potential patient exposures, as well as documenting medications a patient currently tolerates. The route of administration of specific medications can sometimes be overlooked. <h3>Case Description</h3> A 58 year-old woman experienced an acute anaphylactic reaction consisting of cough, dyspnea, abdominal pain, and hypotension with systolic BP in the 80's, occurring 30 minutes after an outpatient surgery for scalp cyst removal. Peri-event tryptase was 30 ug/L and baseline tryptase was 6 ug/L. She had negative skin testing to latex and all local anesthetics used during the procedure. She subsequently had two additional episodes of anaphylaxis at home requiring self-administration of epinephrine and ER evaluation, but no clear inciting cause was identified. She was diagnosed with idiopathic anaphylaxis and started on H1 and H2 blockers, Montelukast, and Doxepin with no recurrence of symptoms. Further history revealed topical Neomycin/polymyxin B/Bacitracin ointment was applied to the scalp wound after cyst removal, and self-applied to the rectal mucosa due to diarrhea with both later episodes. She tolerated applying the ointment to intact skin. Skin testing was positive to bacitracin zinc and Polysporin (bacitracin + polymyxin); testing to neomycin and to polymyxin B sulfate alone were negative. <h3>Discussion</h3> Testing to bacitracin is indicated in peri operative anaphylaxis evaluation. In this case, anaphylactic reactions occurred when this was applied to incision wounds and mucosal surfaces which presumably increase systemic absorption. Bacitracin should be ruled out as a cause of peri operative anaphylaxis even with tolerance of topical bacitracin.