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New yardstick offers diagnostic and treatment guidance for idiopathic anaphylaxis

New yardstick offers diagnostic and treatment guidance for idiopathic anaphylaxis

Guidelines on next steps when there is no clear cause of severe reactions.

ARLINGTON HEIGHTS, Ill. (September 18, 2019) – Many people in danger of the severe allergic reaction known as anaphylaxis understand exactly what they need to avoid to stay safe. For some it’s an allergy to food, for others it can be insect stings, medications, hormones or even physical factors like exercise. But according to the new “Idiopathic Anaphylaxis Yardstick”, there are people for whom diagnosis and treatment of anaphylaxis are difficult because the cause is unknown and therefore labeled “idiopathic.” The yardstick is published in Annals of Allergy, Asthma and Immunology, the scientific journal of the American College of Allergy, Asthma and Immunology (ACAAI).

“Although Idiopathic Anaphylaxis (IA) is relatively rare, medical professionals do run across it,” says anaphylaxis researcher Melody Carter, MD, lead author of the yardstick. “Since avoidance is the first line of defense in preventing anaphylaxis, anyone who hasn’t had the cause identified is at a disadvantage, including physicians who are treating those with anaphylaxis. We developed the “Idiopathic Anaphylaxis Yardstick” to help physicians who might be searching for guidance on next steps after their patient has an anaphylactic reaction of an unknown origin.”

According to the yardstick, a patient history is a vital step in diagnosing IA. Several diseases and disorders have symptoms which mimic anaphylaxis related to an allergy, and some causes of anaphylaxis have been discovered or are better recognized in recent years. Thus, there are many diagnoses labeled as “differential” – not caused by allergy but a reaction to something else. The patient history must include events that happened just before the event – foods that were eaten, drugs taken, activities (ie, exercise) insect stings or exposure to heat or cold. The time, location and duration of the event should also be considered.

“Advances in diagnostics have led to the discovery of disorders that were likely the cause of IA for many patients in the past,” says allergist Phil Lieberman, MD, ACAAI member and co-author of the yardstick. “The yardstick contains a detailed discussion of the disorders that should be considered including alpha-gal, clonal mast disease, drug/alcohol induced flushing, tumor-related flushing and hereditary alpha tryptasemia syndrome. We outline diseases and disorders that can cause anaphylaxis or present with symptoms associated with anaphylaxis in order to assist allergists in examining a broad spectrum of possible causes. We also discuss laboratory tests that are essential diagnostic tools.”

The yardstick has special sections that address pediatric patients and also provides suggestions for how to proceed with patients who don’t respond to other treatments.

The “Idiopathic Anaphylaxis Yardstick” is published online in Annals of Allergy, Asthma and Immunology, the scientific journal of ACAAI. If you are seeking additional guidance on next steps for treating your patient with anaphylaxis, check the yardstick.


The ACAAI is a professional medical organization of more than 6,000 allergists-immunologists and allied health professionals, headquartered in Arlington Heights, Ill. The College fosters a culture of collaboration and congeniality in which its members work together and with others toward the common goals of patient care, education, advocacy and research. ACAAI allergists are board-certified physicians trained to diagnose allergies and asthma, administer immunotherapy, and provide patients with the best treatment outcomes. For more information and to find relief, visit Join us on FacebookPinterest and Twitter.