Patients with meat allergy who take omalizumab may see improvement of symptoms

PHOENIX (Nov. 12, 2026) – The summer of 2026 was a particularly bad season for ticks. And with it came a rising number of cases of alpha-gal syndrome (AGS) thanks to bites from the Lone Star Tick. A new study presented at the American College of Allergy, Asthma and Immunology (ACAAI) 2026 Annual Scientific Meeting shows that a biologic treatment already in use for allergic asthma, food allergies and chronic hives may help protect people with AGS. A separate report on a medically challenging case shows how often doctors miss the allergy, and how it can affect mental health.

AGS occurs following a bite from the Lone Star tick. The bite can make the body react to alpha-gal, a sugar found in red meat such as beef, pork and lamb. It can also be found in some dairy foods and other products made from mammals. Between 96,000 and 450,000 Americans may have AGS. Unlike most food allergies, the reaction often starts hours after eating. That delay makes it hard to connect the reaction to the food.

The first study looked at 64 people with AGS who were treated with omalizumab (Xolair). The medicine is a biologic given as a shot and is already used to treat other allergic conditions. Before treatment, 81% of the patients had experienced a severe, allergic reaction called anaphylaxis. More than half had needed epinephrine.

While taking omalizumab, none of the patients needed epinephrine for a food reaction. Almost all of them (95%) said their reactions happened less often or were less severe. About one in three were able to add some or all red meat or mammal products back into their lives. Side effects were uncommon and mostly mild, such as joint pain. Only two patients stopped the medication because of side effects.

“Even patients who are very careful about avoiding mammalian products can experience accidental exposures and reactions, said Collette M. Tilly, MD, lead author of the study and ACAAI member. “In our study, patients treated with omalizumab had fewer or less severe reactions, and none required epinephrine for a food-related reaction while on therapy. These findings suggest that omalizumab may offer an additional layer of protection for patients living with alpha-gal syndrome.”

The second study describes a medically challenging case. A 66-year-old man who previously had a tick bite broke out in hives, started coughing and had trouble getting enough oxygen. Both times, it happened hours after eating red meat and drinking alcohol. Because he was sometimes able to eat red meat with no problem, AGS was not the first thing suspected by his physician. A blood test finally showed he was highly allergic to alpha-gal. He was given epinephrine to carry and told to avoid red meat. He was also warned that alcohol can make reactions worse.

“In this case, even an experienced physician didn’t think of alpha-gal at first, and that happens frequently,” said Jeffrey Yu, MS, lead author and ACAAI member. “On average, people wait about seven years to get the right diagnosis. As ticks spread to more regions in the US, a simple blood test for alpha-gal could save lives.”

The authors note that in 2025, a New Jersey man became the first known person to die from AGS. They also point out that AGS affects more than the body. About two out of three people with AGS report anxiety or depression. More than half avoid social events that involve food.

“Living with AGS means worrying about every meal,” said Yu. “Patients need mental health support along with good medical care.”

Abstract Title: Omalizumab Eliminates Epinephrine Use and Reduces Anaphylaxis Burden in Alpha-Gal Syndrome

Presenter: Collette Tilly, MD 

Abstract Title: Alpha-Gal Syndrome: An Underrecognized Cause of Delayed Anaphylaxis With Potential Impact on Mental Health

Presenter: Jeffrey Yu, MS

People who think they may have AGS should see a board-certified allergist. An allergist can test for alpha-gal and create a treatment plan. To find an allergist near you, visit AllergyandAsthmaRelief.org The ACAAI Annual Scientific Meeting is Nov. 12-16. For more news and research from the ACAAI Scientific Meeting, go to our newsroom and follow the conversation on X/Twitter #ACAAI26.

About ACAAI

The American College of Allergy, Asthma & Immunology (ACAAI) is a professional medical organization of more than 6,500 allergists-immunologists and allied health professionals, headquartered in Arlington Heights, Ill. Founded in 1942, 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 AllergyandAsthmaRelief.org. Join us on Facebook, Instagram, Threads and X.

OMALIZUMAB ELIMINATES EPINEPHRINE USE AND REDUCES ANAPHYLAXIS BURDEN IN ALPHA-GAL SYNDROME
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C. Tilly^*, S. Commins, Chapel Hill, NC. Introduction: Alpha-gal syndrome (AGS) is an IgE-mediated allergy characterized by delayed hypersensitivity reactions to mammalian-derived food and products. Despite strict avoidance, patients remain vulnerable to accidental exposures and recurrent anaphylaxis requiring epinephrine. Real-world evidence evaluating the impact of omalizumab on severe allergic outcomes in AGS is limited. 
Methods: We conducted a retrospective cohort analysis of 64 patients with confirmed AGS treated with omalizumab between April 2022 and November 2025. Inclusion criteria included a compatible clinical history, positive alpha-gal-specific IgE, and a minimum of 3 months of follow-up. The primary endpoint was food-related epinephrine utilization during therapy. Secondary outcomes included patient-reported changes in reaction burden, mammalian product reintroduction, adverse events, and treatment discontinuation.
Results: Median age was 55 years (range, 20-89 years), and 36/64 (56%) were female. At baseline, 52/64 (81%) had documented anaphylaxis and 34/64 (53%) required epinephrine. Median treatment duration was 23 months (range, 3-83). During omalizumab therapy, no patients required epinephrine for food-triggered reactions. Patient-defined, clinically meaningful reduction in reaction frequency or severity was reported by 61/64 (95%). Mammalian food and/or product reintroduction was achieved in 20/64 (31%), including full reintroduction in 8/64 (13%) and partial in 12/64 (19%). Adverse events were infrequent and predominantly mild, most commonly arthralgias. Only 2/64 (3%) discontinued therapy due to adverse events. 
Conclusion: In this high-risk AGS cohort with substantial baseline anaphylaxis, omalizumab was associated with complete elimination of food-related epinephrine utilization, marked reduction in reaction burden, and favorable tolerability. Prospective studies evaluating anaphylaxis and epinephrine use as predefined clinical endpoints in AGS are warranted.

ALPHA-GAL SYNDROME: AN UNDERRECOGNIZED CAUSE OF DELAYED ANAPHYLAXIS WITH POTENTIAL IMPACT ON MENTAL HEALTH
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J. Yu^*1, J. Ho², A. Luc³, S. Yee⁴, M. Lee-Wong⁵, 1. New York, NY; 2. Philadelphia, PA; 3. Hempstead, NY; 4. Nyack, NY; 5. Brooklyn, NY.

Introduction
Alpha-gal syndrome (AGS) is an IgE-mediated allergic reaction to galactose-alpha-1,3-galactose, a carbohydrate introduced into the bloodstream via the Lone Star tick (Amblyomma americanum). Despite an estimated 96,000 to 450,000 affected Americans, AGS remains underdiagnosed, with an average time to diagnosis of 7 years. In 2025, a 47-year-old New Jersey man became the first documented AGS fatality, highlighting the need for broader clinical recognition.

Case Description
A 66-year-old male with a history of tick bite, asthma, and urticaria presented with two episodes of delayed-onset hives, coughing, and oxygen desaturation to 90 percent after consuming red meat and alcohol. AGS was not the primary clinical suspicion, especially given toleration of red meat between episodes. Alpha-gal IgE testing returned markedly elevated at greater than 100 kU/L, with specific IgE confirming sensitization to beef (52.00 kU/L), lamb (29.80 kU/L), and pork (28.80 kU/L). Tryptase was 5.3 mcg/L, ruling out mastocytosis. The patient was prescribed epinephrine and counseled on red meat avoidance and alcohol as a known cofactor.

Discussion
This case illustrates a classic but frequently missed presentation of AGS. The diagnosis was not the initial clinical impression of an experienced physician and was identified only through broad serologic testing, reflecting a systemic awareness gap. As tick populations expand, routine alpha-gal IgE screening may be lifesaving. Two-thirds of AGS patients report anxiety or depressive disorders, and 63 percent avoid social situations involving food, underscoring the need for integrated mental health support alongside routine screening protocols.