What to know about alpha-gal syndrome, the life-threatening meat allergy
caused by tick bites
[June 15, 2026]
By MATTHEW PERRONE
WASHINGTON (AP) — It's common knowledge that ticks can spread infections
that cause serious illnesses, including Lyme disease. Now health
officials are trying to raise awareness of a lesser-known problem: a
life-threatening allergy to meat triggered by tick bites.
The problem, known as alpha-gal syndrome, was first linked to a
particular species of ticks about 15 years ago. But cases are on the
rise as more people report symptoms such as hives, diarrhea and
itchiness after eating as little as a mouthful of meat and — in some
cases — dairy. The allergy doesn’t impact consumption of seafood or
poultry. Chicken, turkey and eggs are all OK to eat.
For years, the standard treatment has involved avoiding foods that come
from cows, pigs and lambs while carrying an epinephrine injector in case
of medical emergency. But regulators recently approved the first drug
for the condition, and more therapies may be on the way.
Here's what to know about alpha-gal syndrome:
What causes it?
Unlike other tick-borne illnesses, such as Rocky Mountain spotted fever,
alpha-gal syndrome isn't caused by a bacteria or a virus. Instead, it
occurs when the human immune system triggers an allergic response to a
type of sugar, known as alpha-gal.
Alpha-gal is found in the meat of most mammals, but not in humans or
other primates. It's also found in the saliva of certain ticks.
When eaten, the sugar is normally harmless. But when ticks bite through
the skin, they can introduce the sugar directly into the bloodstream.
That triggers the development of antibodies — immune system proteins
that fight off foreign invaders — that quickly learn to identify and
attack alpha-gal sugar molecules.
“It turns out that the skin is a fantastic way to make an allergic
response," said Dr. Scott Commins, an alpha-gal syndrome researcher at
the University of North Carolina. "If this all happened orally, and we
were eating alpha-gal like we do with steaks or barbecue, then we
wouldn't become allergic.”
People that develop the antibodies will often experience a strong
allergic reaction a few hours after consuming meat or dairy. But it can
take weeks or months for the problem to develop, with the severity of
symptoms often increasing over time.
Why are more people being diagnosed with alpha-gal syndrome?
Experts point to increased awareness among health professionals and the
public.
“I think part of it is more people have learned about it and are on the
watch for this syndrome,” said Maria Diuk-Wasser, a Columbia University
researcher who studies tick-borne diseases.
But rising cases also reflect the expanding habitat range of the lone
star tick, the primary source of the condition in the U.S. Often
identifiable by a white dot on its back, the lone star tick is most
common in the eastern and southern U.S. But in recent years it's been
reported in new parts of the country, including the Great Lakes region
and as far north as Martha's Vineyard in Massachusetts.
Researchers worry that other types of ticks, including blacklegged
ticks, may also increasingly spread the condition.
Roughly 450,000 Americans are estimated to have developed the allergy,
according to a 2023 study by the the Centers for Disease Control and
Prevention.
When should someone get tested?
People usually seek medical attention after experiencing worrisome
symptoms, including hives, dizziness, difficulty breathing and swelling
of the lips, throat, tongue or eyelids. Some people may only experience
digestive issues, including diarrhea, stomach pain, vomiting and nausea.
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This photo provided by the U.S. Centers for Disease Control shows an
adult female lone star tick crawling on a blade of grass in 2023.
(Lauren Bishop/CDC via AP)
 Doctors diagnose the allergy based
on results from a blood test, symptoms and other details reported by
the patient, including whether they recall any recent bug bites.
The blood test detects the presence of alpha-gal antibodies, but not
all patients with a positive result develop the condition. Sometimes
the test can also be wrong.
“The blood test in and of itself is great, but you can’t rely on
that just for diagnosis. You need the actual symptoms too," Commins
said. “In the allergy world, we have a lot of trouble with false
positives on blood tests.”
Which foods are off limits?
Doctors generally advise patients to avoid beef, pork, lamb and
other meats from mammals. Some people are still be able to consume
dairy products from these animals, including milk, cheese and
butter. Those with particularly severe reactions may need to avoid
foods made with other animal byproducts such as gelatin, which is
found in marshmallows and gummy bears.
One rare exception: meat from a small number of pigs that have been
genetically modified to not produce alpha-gal. Approved for
consumption by the Food and Drug Administration in 2020, the pigs
are bred as part of an experimental effort to harvest animal organs
for transplantation into humans. Deactivating the alpha-gal gene was
a critical first step to make sure the human immune system wouldn't
immediately reject the foreign organs. Meat from these so-called
“GalSafe” pigs is available from a company called Amaroo Hills.
People with the syndrome may also have to avoid certain medical
products and implants. For instance, many heart valves are made from
cow or pig parts.
How long does it last?
The allergy can fade away in some people after several years.
Commins has seen that happen in about 15% to 20% of his patients.
But it's critical to avoid new tick bites.
What treatments are available?
In 2024, the FDA approved an injectable drug called Xolair for a
variety of food allergies, including alpha-gal syndrome. The drug
doesn't reverse the condition but helps reduce severe allergic
reactions after accidental exposure to meat.
The drug was first approved more than 20 years ago for patients with
hard-to-control asthma. It works by reducing the release of
biological chemicals that cause inflammation and other allergic
reactions.
Commins and other researchers hope to study other previously
approved drugs as new options for patients.
“There are certain (biologic drugs) out there nowadays that
interfere with the allergic signaling," Commins said. "We think that
if you were on one of those — or if you got one quickly enough after
a tick bite — perhaps it could interfere with the entire allergic
response process.”
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Associated Press video journalist Mary Conlon contributed to this
story.
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