New research lends a hint as to why women tend to experience severe allergic reactions — including rashes, swelling, trouble breathing, and heart attacks — more frequently than men. These life-threatening events, called anaphylaxis, might be influenced by estrogen levels, according to the National Institutes of Allergy and Infectious Diseases.
The researchers found female mice experience longer and more severe anaphylactic reactions, The Washington Post reports. Estrogen enhances an enzyme lining blood vessels, which in turn increases nitric oxide production. That drops blood pressure and causes swelling. Once the enzyme is blocked, male and female mice have similar allergic reactions.
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