Alpha-gal syndrome – tick-borne food allergy infesting Orange County

A photo of a lone star tick carrier of alpha-galactose sugar that causes a recently discovered syndrome in humans called alpha-gal syndrome. Photo by Dr. Scott P. Commins, M.D., Ph.D


By Richard Greene, M.D., Ph.D.

ORANGE COUNTY-Mary Ellen Smith (name changed upon request) was attending a business conference at a remote mountain town in North Carolina. She had just finished a steak dinner at the banquet on the last day of the meetings when she suddenly had trouble breathing. The sense of panic and urgency overwhelmed her, “I was able to tell a friend near me that I could not breathe, and it was the last thing I remember,” said Smith.

Smith luckily got immediate help by being transported and given medication for anaphylactic shock. The cause, however, remained a mystery since she had no known food allergies, had not been stung or bitten recently, and was generally in excellent health.

It was when she returned home to Chapel Hill, and through her own year of investigations, she ultimately asked her doctor to do a blood test for alpha galactose syndrome (alpha-gal). Alpha-gal is not an infectious disease. It is a tick-borne food allergy to alpha-gal, a sugar not found in people but a normal component of meat from beef, pork, and lamb, as well as dairy products and gelatin used in capsules containing medicine.

“That was five years ago and I have not had any red meat or anything prepared in beef broth since then,” said Smith.

Smith is one of the numerous cases in Orange County that has come to light with the use of a blood test, not often given when treating cases of severe allergic reactions because the food allergy was not well-known.

The U.S. Centers for Disease Control recently posted information in July about a newly discovered food allergy called alpha galactose syndrome, estimating over 110,000 cases in the United States from 2010 to 2022. Most of these cases are concentrated in the Southeast United States, where deer and lone star ticks are prevalent. The CDC indicated the estimates of the number of United States cases are likely to be lower than the true numbers, because a recent CDC survey of primary care clinicians indicated that about half of them had never heard of alpha-gal syndrome.

Close-up photo of a lone star tick. Provided by Dr. Scott Commins.

Alpha-1,3-galactose (alpha-gal) syndrome is not an infectious disease. It is a tick-borne food allergy to alpha-gal, a sugar not found in people. The alpha galactose sugar is a normal component of meat from beef, pork and lamb as well as dairy products and gelatin capsules. The tick-borne alpha-gal allergy occurs when a person is bitten by a tick with alpha-gal in its saliva. According to the Mayo Clinic, alpha-gal makes people allergic to red meat and other products made from mammals. Note that fish, chicken and other fowl do not have alpha-gal sugar in their bodies, and eating food from these animals does not trigger an allergic reaction.

The tick transfers the alpha-gal sugar through its bite. Alpha-gal sugar is a foreign substance in people and triggers an immune reaction stimulating the person to make allergic antibodies to the alpha-gal. When the person subsequently eats red meat or other animal foods containing alpha-gal, the allergic antibodies are engaged and an allergic reaction may occur. These can range from a mild rash to severe, life-threatening anaphylactic shock that requires immediate emergency treatment.  Other symptoms can include swelling of the face, wheezing and shortness of breath and stomach distress, including diarrhea or vomiting.

Diagnosis of alpha-gal syndrome is complicated by the fact that the allergic symptoms may not occur immediately after eating food containing the sugar but could occur from 2 to 6 hours after the meal.

Dr. Scott P. Commins, M.D., Ph.D. at the University of North Carolina, Monday, February 29, 2016. Photo by Chris Polydoroff

Dr. Scott P. Commins, M.D., Ph.D., Medical Director of the University of North Carolina Allergy and Immunology Clinic. He is one of the leading experts on alpha-gal syndrome, told TLR the syndrome is unique in terms of public health and policy.

“The delayed reactions make it more difficult to diagnose than traditional food allergies. Also, we believe there is very likely an equity gap.  Allergists do not exist in every county and some patients would have to travel far to see a specialist.  This probably contributes to a fair amount of undiagnosed cases.  The new survey data suggests that primary care providers may not be as well versed in recognizing and diagnosing alpha-gal syndrome.” Dr. Commins is actively engaged in research on and in the clinical management of people with alpha-gal syndrome. He estimates approximately 1,500 known cases in Orange County this year.

 A blood test for alpha-gal syndrome can detect antibodies to the sugar in the blood. If you suspect that you have alpha-gal syndrome, you can see an allergist or ask your physician to test your blood for antibodies to the alpha-gal sugar.

There is no specific treatment for alpha-gal syndrome other than avoiding foods that contain alpha-gal sugar. However, Dr. Commins said, “The allergic response can resolve over time – typically 3-5 years after the initiating tick bite. Unfortunately, additional or subsequent tick bites will ‘reset’ the clock in most folks.”

Since the syndrome is relatively new, Commins said, “Patients need to understand that they might need to educate their providers about a diagnosis they believe they have, and be patient but persist if they think they have this.  Practitioners may need to consider referring to a specialist and possibly taking the free online educational webinar the CDC offers.”

Many people get tick bites in their own yard or neighborhood. Ticks do live in grassy, bushy or wooded areas, or on animals; however, many folks overlook the exposure to ticks nearby their own home. Spending time outside walking your dog, camping, gardening or hunting could bring you in close contact with ticks, according to Commins.

It is recommended to use Environmental Protection Agency (EPA) registered insect repellents containing DEET and picaridin. Treat clothing and gear such as boots, pants, socks and tents with products containing 0.5% permethrin.

The CDC recommends checking for ticks frequently, especially under the arms, in and around the ears, inside the belly button, behind the knees, between the legs, around the waist and on the hairline and scalp. And remove ticks promptly.  Shower soon after being outdoors.

The lone star tick is the second most commonly found tick in North Carolina, the first is the American dog tick, the third is the brown dog tick that rarely attacks humans and finally, the black-legged tick, the carrier of Lyme disease.

Michelle Cassell, Managing Editor, contributed to this article

Richard Greene, M.D., Ph.D.:
Education:  Johns Hopkins School of Medicine – M.D.   M.I.T. Ph.D. in Molecular Biology.
Research in molecular biology and health policy.
Research administration:  Directed the national medical research program for the U.S. Department of Veterans Affairs.

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