A study by researchers of the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), may shed light on why women suffer more frequent and more severe instances of anaphylaxis than men.
Anaphylaxis – a life threatening allergic reaction triggered by foods, medication, and animal stings and bites – occurs when immune cells release enzymes that cause tissues to swell and blood vessels to widen. Clinical studies have shown that women experience anaphylaxis more often than men, though the mechanism for this has not been clearly understood.
NIAID researchers found that female mice experienced more severe and longer lasting anaphylactic reactions than males. They discovered that Estradiol – a type of estrogen – enhances the effect of endothelial nitric oxide synthase (eNOS), an enzyme that causes a number of symptoms of anaphylaxis.
When they blocked eNOS, they found the gender disparity of anaphylaxis symptoms disappeared, with the severity of anaphylactic reactions of female mice lessening to that of males.
Though this mechanism of Estradiol has yet to be confirmed in humans, it may someday yield more effective medications to treat anaphylaxis in women.