A type of estrogen, called estradiol, may explain why women often experience more severe allergies than men.
Researchers at the U.S. National Institutes of Allergy and Infectious diseases found in mice that estradiol enhanced an enzyme that is involved in life-threatening allergic reactions.
Anaphylaxis, a severe allergic reaction, can be triggered by some foods, medication and insect stings and bites. Anaphylaxis occurs when immune cells release proteins that cause tissues to swell. Symptoms include flushing, trouble breathing, shock or heart attack.
Estrogen influences blood vessels, and researchers found the hormone stimulates more severe and longer-lasting anaphylaxis in female than in male rodents.
By giving estrogen-blocking agents to the female mice, researchers blunted their allergic responses to a degree similar to the male animals.
Investigators say more work is needed before a similar treatment is given to people to prevent anaphylaxis.
The study was published in The Journal of Allergy and Clinical Immunology.