This report describes a rare, life-threatening allergic reaction to dacarbazine occurring after an initially tolerated dose in a patient with classical Hodgkin lymphoma. Dacarbazine is generally well tolerated aside from expected hematologic toxicities, but rare anaphylactic events have been documented. The case underscores that hypersensitivity can present on subsequent exposures even when the first administration produced no immediate adverse events.
The patient was a 69-year-old man with classical Hodgkin lymphoma. He was planned to receive combination therapy consisting of nivolumab, doxorubicin, vinblastine, and dacarbazine (abbreviated as N + AVD), administered on a day 1 and day 15 schedule every 28 days.
Cycle 1 day 1 was completed without complications. On cycle 1 day 15, shortly after starting the dacarbazine infusion, the patient developed an acute, severe allergic reaction.
The anaphylactic reaction began approximately 5 minutes after the start of the dacarbazine infusion. Clinical manifestations reported included:
These features indicate immediate systemic hypersensitivity consistent with anaphylaxis and prompted urgent intervention.
The dacarbazine infusion was stopped immediately upon recognition of the reaction. Initial pharmacologic measures given were 10 mg intravenous chlorphenamine and 200 mg intravenous hydrocortisone; these did not result in clinical improvement.
Because hypoxia and laryngeal edema persisted, the team administered 0.3 mg intramuscular epinephrine, after which the patient’s respiratory status and laryngeal swelling improved. Following epinephrine, oxygen saturation rose from 82% to a range of 90–93%.
Given the risk of a biphasic anaphylactic reaction — a recurrent set of symptoms that can arise after initial resolution — the patient was transferred to the intensive care unit for close monitoring. He remained hemodynamically stable during his ICU observation and did not develop reported complications during that period.
Dacarbazine was discontinued permanently following this event.
After dacarbazine cessation, the patient’s lymphoma-directed therapy continued with the remaining agents: nivolumab, doxorubicin, and vinblastine (N + AV). He completed five cycles of this adjusted regimen and achieved a complete metabolic response as reported by the authors.
This case highlights several clinically important points:
Anaphylactic reactions to chemotherapy agents such as dacarbazine can occur despite prior uneventful exposure; tolerance of an initial dose does not exclude the risk of a subsequent severe hypersensitivity reaction.
Early recognition of anaphylaxis features — hypoxia, airway edema, cutaneous signs, and systemic manifestations — and prompt administration of intramuscular epinephrine are critical steps that produced clinical improvement in this patient when initial antihistamine and corticosteroid treatment alone did not suffice.
Transfer to a higher level of care for observation is advisable given the possibility of a biphasic reaction after apparent recovery.
When a culprit agent is suspected to have caused an anaphylactic event, discontinuation of that agent is a commonly chosen management approach; in this instance, dacarbazine was stopped and the remaining regimen was continued, with reported complete metabolic remission.
This report serves as an important reminder for oncology and critical care teams to maintain vigilance for immediate hypersensitivity reactions during all chemotherapy infusions, including subsequent doses. Clinicians should ensure rapid access to epinephrine and airway management resources during infusions and consider alternative regimens when a life-threatening allergic event implicates a specific chemotherapeutic agent.
Note: The source article is a single-case report; detailed diagnostic testing for mechanism (for example, skin testing or serum tryptase levels) was not reported in the abstract and therefore is not available from the provided source.