While rare, some people experience recurrent episodes of anaphylaxis—a life-threatening allergic reaction that causes symptoms such as the constriction of airways and a dangerous drop in blood pressure—for which the triggers are never identified. Recently, researchers at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, found that some patients’ seemingly inexplicable anaphylaxis was actually caused by an uncommon allergy to a molecule found naturally in red meat. They note that the allergy, which is linked to a history of a specific type of tick bite, may be difficult for patients and health care teams to identify.
