Anaphylactic reaction to the second dose of dacarbazine following initial exposure in patient with hodgkin lymphoma.

IntroductionDacarbazine is generally well-tolerated, apart from its hematologic toxicities; however, rare and life-threatening anaphylactic reactions have been reported. We aimed to describe a rare case of anaphylactic reaction to dacarbazine following a previously tolerated first dose.Case ReportWe report a case of a 69-year-old male patient with classical Hodgkin lymphoma, who was planned for nivolumab, doxorubicin, vinblastine, and dacarbazine (N + AVD) combination, day 1 and 15 every 28 days. The patient received day 1 of cycle#1, without any complications. On day 15, the patient developed a severe anaphylactic reaction 5 min after the start of dacarbazine infusion. The reaction was manifested by hypoxia, shivering, itching, and laryngeal edema.Management & OutcomePatient required immediate interruption of dacarbazine infusion and received 10 mg of intravenous chlorphenamine and 200 mg of intravenous hydrocortisone initially with no improvement. Hypoxia and laryngeal edema improved following the administration of 0.3 mg intramuscular epinephrine. The patient was transferred to the intensive care unit for close monitoring due to increased risk of biphasic anaphylactic reaction, in which symptoms can recur after initial resolution. Oxygen saturation improved from 82% to 90-93%, and the patient remained hemodynamically stable without complications. Dacarbazine was discontinued. Patient continued nivolumab, doxorubicin, and vinblastine (N + AV) for five cycles, and achieved complete metabolic response.DiscussionThis case highlights that anaphylactic reaction to dacarbazine may occur despite prior tolerance to the first dose. Physicians should suspect reaction during subsequent infusions of dacarbazine, even when initial cycle is tolerated.