FOR THE PEOPLE
When Melody Adams ’ 85 woke up covered in an itchy rash, her husband grabbed
the Benadryl and Adams jumped in the
shower, thinking, “I bet it was those weird
Asian spices I ate.” But the hives reappeared a week later. Then it happened
again, and again, and again, always in the
middle of the night.
One day, a rare midday trip to a fast-food joint at the mall caused her to break
out in hives around dinnertime, with the
added bonus of vomiting.
“That’s when I thought it was the red
meat,” Adams remembered.
At a friend’s birthday party, she struck
up a conversation with another guest —
Scott Commins, an allergist and researcher
at UNC’s Thurston Arthritis Research
Center. Commins told her he specializes
in a weird tick-borne meat allergy called
“I think I have that!” Adams blurted.
A week later, Commins ran a simple blood
test — a test he helped develop — to
confirm she was now allergic to a sugar in
red meat and pork called alpha-gal, which
is short for galactose-alpha- 1,3-galactose.
This sugar is not in poultry, fish or,
importantly, in humans.
Typically, when we eat meat, antibodies
in our digestive tract recognize alpha-gal
— and all sugars, fats and proteins in food
— but the antibodies do not trigger allergic
reactions. These antibodies fall into two
classes of immunoglobulins.
But people allergic to meat have
different antibodies that can cause a violent
immune response to alpha-gal. This
involves a third class of immunoglobulins
(call it IgE), which go haywire in the
presence of alpha-gal, causing symptoms
that include abdominal pain, diarrhea,
vomiting, hives, itchy hands, trouble
swallowing and anaphylactic shock — the
medical emergency that requires a 911 call
Commins and a UNC colleague,
Maya Jerath, are conducting research
to characterize this relatively new
phenomenon, determine the pathology
and hopefully develop treatments. They
are two of the few researchers in the U.S.
working on this strange allergy they simply
refer to as alpha-gal. And it turns out the
culprit that causes people such as Adams
to conjure up these antibodies is our
summertime arch-nemesis, the tick.
“To be honest, we can’t say for sure
exactly how ticks cause the allergy,” Com-
mins said. “But we think we know, and
we’re trying to prove it.”
Commins’ and Jerath’s working hypoth-
esis is that a tick bites an animal, such as a
dog, cow, cat, pig or deer, and then falls
off. The tick has alpha-gal in its saliva from
the blood meal. Then it bites a human,
injecting alpha-gal under the person’s skin.
This alpha-gal enters a lymph node and
triggers the creation of the IgE antibodies.
These antibodies become soldiers-in-wait-
ing throughout the body, including the
digestive tract. When this person eats meat,
alpha-gal binds to the specific IgE antibod-
ies, triggering an allergic reaction.
Unfortunately, the allergy is not so easy
to recognize as an allergy. Symptoms don’t
appear until three to six hours after a meal.
Sometimes, a person eats meat and nothing
happens. But the next time the person eats
meat, he or she can break out in hives.
Some people have severe gut discomfort.
People don’t typically associate that with an
“I suspect there are a lot of undiagnosed
people,” Commins said. “They might go
to a GI specialist and be diagnosed with
irritable bowel syndrome, which is a sort
of catch-all diagnosis. But in reality, some
of these people are probably allergic to
It’s the hives or trouble breathing that
clue people in to a potential allergy. Even
then — say you land in the ER due to a
swollen airway or because you passed out
The Mystery Meat Allergy:
You Don’t Hate Ticks Enough?