A man with systemic mastocytosis (SM) experienced a fatal allergic reaction after being stung by a wasp despite quickly receiving epinephrine, according to a recently published case report in the International Journal of Legal Medicine.
The case involved a 41-year old man with indolent SM — the most common form of SM, which is characterized by the abnormal production and accumulation in the body of mast cells (a type of immune cell).
“Adult male patients suffering from indolent systemic mastocytosis (especially in cases without previous skin issues) are at extremely high risk of severe and recurrent systemic reactions to hymenoptera stings,” the report’s authors said. “Hymenoptera” is a term used by scientists to refer to insects like bees, wasps and ants.
Although previous bee and wasp stings had not been life-threatening and had only caused low blood pressure and fainting, exposure to bee and wasp venom had sensitized his immune system, making it more reactive. The combination of SM and previous stings put the man at very high risk of serious anaphylaxis, the authors said.
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The man was working in a vineyard when he was stung by an insect, started having trouble breathing and collapsed. His mother, who arrived quickly, gave him an epinephrine injection using an auto-injector (such as an EpiPen), but he soon lost consciousness and his heart stopped. Although doctors continued trying to revive him, he passed away in the hospital 12 hours after the sting.
In most cases of fatal allergic reactions, doctors don’t have blood test results from while the patient was still alive. This is because these lab tests take time and are not considered helpful in emergency clinical diagnosis and treatment.
In this case, however, the patient was considered as a possible organ donor and doctors took blood samples while he was in intensive care. Along with the autopsy and other evidence, these blood samples helped doctors confirm the man’s cause of death.
When the blood samples were analyzed, results showed that the patient had extremely high levels of tryptase, a chemical released during allergic reactions, confirming anaphylaxis. Additional tests showed the patient had a mild allergy to honeybee venom, but a much stronger allergy to a type of wasp called Polistes Dominulus.
Unfortunately, the patient had just started allergy treatment (venom immunotherapy, or VIT). He had completed one cycle (eight sessions) for bee venom but only had one session for wasp venom, meaning his body wasn’t yet protected against wasp stings. Based on this information, doctors concluded that the man died from a severe allergic reaction to a wasp sting.
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