NOV 29, 2017 5:51 AM PST

Rare Red Meat Allergy to Blame for Unexplained Anaphylaxis

WRITTEN BY: Kara Marker

Unexplained bouts of anaphylaxis, a serious allergic reaction, could be a direct result of a rare allergy to meat originating from a tick bite. From the National Institute of Allergy and Infectious Diseases (NIAID), a new study showed that, at least for some “mystery cases” of anaphylaxis, a rare allergy to a molecule in red meat was to blame.

When the immune system overreacts to an allergen and releases inflammatory chemicals all over the body, the result is a life-threatening process called anaphylaxis. Airway constriction, sudden drop in blood pressure, rash, wheezing, vomiting, diarrhea, and even a “feeling of impending doom” are all symptoms of this dangerous response, which is often a result of food allergies. Anaphylaxis requires an injection of epinephrine to stop the reaction, and sometimes the cause for anaphylaxis is unknown.

In a study with 70 participants with “unexplained frequent anaphylaxis,” six people tested positive for an “alpha-gal” allergy, a rare allergy triggered by a sugar molecule in beef, pork, lamb, and other red meats called galactose-a-1,3-galactose.

All six of these participants shared certain antibodies to alpha-gal in their bloodstream, IgE antibodies that are generally associated with allergies. A diet free of red meat prevented anaphylaxis for all six study participants. Researchers followed them for a time between 18 months and three years.

The prevalence of the alpha-gal allergy is mostly unknown; because of its rarity, typical allergy tests do not look for alpha-gal antibodies. Plus, allergic reactions to alpha-gal do not appear within minutes of eating red meat, unlike common food allergies like peanuts and shellfish. Instead, a person allergic to alpha-gal could go up to six hours before experiencing any allergic reactions.

"This unusually long time gap between a meal and an allergic reaction is probably a big reason that alpha-gal allergies are often initially misdiagnosed," explained the NIAID’s Dean Metcalfe, MD. "If you start to have trouble breathing in the middle of the night, you probably are not going to blame the hamburger you had for dinner."

This is an adult female Lone Star tick climbing on a plant. Bites from the juvenile form of this species, sometimes called seed ticks, are linked to the development of red meat allergy. Credit: NIAID

However, scientists do see a trend in where cases of alpha-gal allergies tend to occur: the Southeast region of the United States and certain areas of New York, New Jersey, and New England. This is likely due to the allergy’s connection to the “Lone Star tick,” Ambylomma americanum. Unfortunately, other than understanding that there is a connection, researchers do not know how the Lone Star tick bite causes the allergy to alpha-gal to develop.

"Alpha-gal allergy appears to be yet another reason to protect oneself from tick bites," said NIAID Director Anthony S. Fauci, MD. "Food allergies can range from an inconvenience to a life-threatening condition and pose a serious and growing public health problem that urgently requires more research."

The present study is published in the journal Allergy.

Sources: University of Florida Entomology & Nematology, American Academy of Allergy, Asthma, & Immunology, NIH/National Institute of Allergy and Infectious Diseases

About the Author
  • I am a scientific journalist and enthusiast, especially in the realm of biomedicine. I am passionate about conveying the truth in scientific phenomena and subsequently improving health and public awareness. Sometimes scientific research needs a translator to effectively communicate the scientific jargon present in significant findings. I plan to be that translating communicator, and I hope to decrease the spread of misrepresented scientific phenomena! Check out my science blog: ScienceKara.com.
You May Also Like
DEC 24, 2020
Cardiology
The Detrimental Health Impact of Ultra-Processed Foods
DEC 24, 2020
The Detrimental Health Impact of Ultra-Processed Foods
Prepared and highly processed foods have become very common, and they've been linked to negative health effects like obe ...
JAN 06, 2021
Genetics & Genomics
Junk DNA Helps Control the Body Clock
JAN 06, 2021
Junk DNA Helps Control the Body Clock
Our bodies run on a kind of molecular clock, which helps regulate and time certain functions beyond just waking and slee ...
JAN 11, 2021
Cancer
Sentinel Nodes Could Reveal a Tumor's Prognosis
JAN 11, 2021
Sentinel Nodes Could Reveal a Tumor's Prognosis
For many diseases, the ability to quickly and effectively diagnose or prognose a patient is critical. If caught early on ...
JAN 14, 2021
Health & Medicine
Where There's Recreational Cannabis Junk Food Sales Are Higher
JAN 14, 2021
Where There's Recreational Cannabis Junk Food Sales Are Higher
In areas where recreational cannabis has been legalized, sales of “junk” foods such as ice cream, cookies an ...
JAN 17, 2021
Genetics & Genomics
New Insights Into Kabuki Syndrome
JAN 17, 2021
New Insights Into Kabuki Syndrome
Kabuki syndrome is a rare multisystemic disorder that causes delays in growth, distinctive facial features, short statur ...
JAN 24, 2021
Genetics & Genomics
Rare Neurodevelopment Disorder LINKED is IDed
JAN 24, 2021
Rare Neurodevelopment Disorder LINKED is IDed
Scientists have now characterized a genetic disorder called linkage-specific-deubiquitylation-deficiency-induced embryon ...
Loading Comments...