People who take cholesterol-lowering medications may face a higher risk of severe allergic reactions to stings from insects in the order Hymenoptera, a group that includes bees, yellowjackets, wasps, hornets and fire ants, according to a new study published in The Journal of Allergy and Clinical Immunology: In Practice.
Many people with systemic mastocytosis (SM) have a hymenoptera venom allergy and are already at significant risk of suffering from a severe reaction to a sting.
In this multinational cohort study, researchers reviewed records of patients with Hymenoptera venom allergy from Canada, the United States and Germany and identified 778 patients with a systemic presentation of the allergy between 2010 and 2023. A systemic reaction spreads beyond the sting site to affect the whole body, with symptoms such as widespread hives, flushing, swelling, trouble breathing, stomach upset or a drop in blood pressure.
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Each patient’s reaction was rated on the Brown scale, which grades reactions as mild, moderate or severe. Among all 778 patients, 29% had a severe reaction, while 71% had a mild or moderate one. But among the 111 patients taking cholesterol drugs, nearly half had a severe reaction.
The analysis showed a twofold difference in the odds of a severe reaction among patients taking cholesterol-lowering medications, even after adjusting for factors such as age, sex, certain blood pressure and heart medications, respiratory conditions, and mast cellMast cell A type of white blood cell produced in the bone marrow. They help defend against infections and play a key role in allergic reactions. In SM, mast cells become overactive and build up throughout the body. disorders, which include systemic mastocytosisMastocytosis Rare disease caused by the buildup of mast cells. Cutaneous mastocytosis primarily affects the skin and is more common in children, while systemic mastocytosis affects internal organs and is more common in adults..
Moreover, the researchers ran an additional analysis to see whether existing cardiovascular disease — conditions affecting the heart and blood vessels — might influence the difference, and found it did not, though they noted that the number of patients with such conditions was small.
The proposed explanation centers on platelet-activating factor (PAF), a molecule that drives many of the dangerous effects of anaphylaxisAnaphylaxis A severe allergic reaction that can turn fatal without treatment. Patients with SM are at a higher risk of developing anaphylaxis..
The body normally breaks down PAF using an enzyme. Earlier research has linked lower levels of that enzyme to more severe, and even fatal, reactions. Because the enzyme travels through the blood largely attached to LDL — the “bad” cholesterol these drugs lower — the authors propose that reducing LDL may also reduce the enzyme, allowing PAF to linger and reactions to intensify.
The study’s assessment for mast cell disorders was not standardized across the full cohort, and only 3% of patients were recorded as having hereditary alpha tryptasemia or mastocytosis — a figure the authors say likely undercounts the true number. That gap matters, because earlier research suggests up to 30% of people with Hymenoptera venom allergy may have an underlying clonal mast cell diseaseMast cell disease A group of conditions in which mast cells behave abnormally by building up in excess, releasing chemicals too easily or both. Includes mastocytosis, mast cell activation syndrome and hereditary alpha-tryptasemia. such as SM.
Importantly, the findings are not a reason to stop taking prescribed medications — cholesterol-lowering drugs such as statins are important for reducing cardiovascular risk and preventing serious, potentially fatal events such as heart attacks. Instead, the authors suggest patients at risk for anaphylaxis talk with their allergist about precautions such as venom immunotherapy and always carrying an epinephrineEpinephrine Also called adrenaline, this hormone is used in emergency situations to reverse symptoms during a severe allergic reaction (anaphylaxis). auto-injector.
The researchers call for larger studies to confirm the results.
Read more about Hymenoptera venom immunotherapy: “Should people with SM consider venom immunotherapy?”
