Idiopathic Anaphylaxis: Could It Be Alpha Gal Syndrome? (Recording)

This webinar was recorded on October 22, 2026

A tick bite can lead to alpha-gal syndrome, an allergy that may cause symptoms hours after a meal.

Imagine waking at 3 a.m. with hives and trouble breathing. You ate dinner hours ago. Nothing seemed wrong then.

When testing does not reveal a cause, healthcare professionals may call the reaction idiopathic anaphylaxis. This means a severe allergic reaction with no known trigger.

But there may be a missing clue: a tick bite.

In this webinar, Scott Commins, MD, PhD, explored the link between unexplained reactions and alpha-gal syndrome. Commins is an allergy specialist and researcher at the University of North Carolina at Chapel Hill.

What Is Alpha-Gal Syndrome?

Alpha-gal syndrome, or AGS, is an allergy to a sugar called alpha-gal. It is found in beef, pork, lamb, venison and other meat from mammals.

After certain tick bites, the immune system may begin treating this sugar as a threat. Later exposure can cause an allergic reaction.

The timing can make AGS hard to spot. Unlike many food allergies, symptoms often begin hours after eating, when a person may already be asleep. Symptoms can include hives, stomach pain, vomiting, swelling or trouble breathing. Some reactions cause anaphylaxis, which can be life-threatening.

Four Clues That May Help Explain Reactions

A meal alone may not tell the whole story. In his published review, Commins describes several factors that can change how and when people react:

1. Fat content. Fatty meat and foods made with animal fat may be more likely to cause reactions.
2. Amount eaten. The amount can affect a reaction, but a small serving should not be assumed safe.
3. Alcohol and activity. Drinking alcohol or being active may increase the chance of a reaction. Activity can include yardwork or physical labor.
4. New tick bites. Another bite may increase sensitivity, changing how someone responds to foods they could eat before.

Reactions can vary. A person may eat a food without symptoms one day and react to it another day. That pattern does not rule out AGS.

Alpha-Gal Triggers Can Go Beyond Meat

For some people, managing AGS means checking more than the main dish. Animal fat, meat broth and gelatin made from beef or pork may also cause reactions.

Dairy needs vary, too. Many people with AGS can still have milk or cheese, while others need to avoid them.

Certain medicines, vaccines and medical products may contain ingredients from mammals. Examples include some gelatin capsules, the blood thinner heparin and heart valves made from animal tissue. These products do not cause reactions in everyone with AGS.

Review possible triggers with an allergist and pharmacist. They can help assess specific products and find suitable options when needed. Do not stop a prescribed medicine or skip a vaccine without discussing it with your healthcare professional.

Why Alpha-Gal Syndrome Can Be Missed

Awareness remains a challenge. In a 2022 healthcare survey, 42% of 1,500 healthcare professionals had never heard of AGS. Another 35% were not confident diagnosing or managing it.

The number of people affected is also uncertain. More than 110,000 suspected U.S. cases were identified from 2010 through 2022. Accounting for people who may not have been tested, researchers estimated that as many as 450,000 people might have been affected. That estimate is not a count of confirmed diagnoses.

What to Do If You Suspect Alpha-Gal Syndrome

If you have unexplained reactions hours after meals, ask your healthcare professional whether AGS could be a cause. Share what you ate, when symptoms began and any tick bites or outdoor exposure you remember.

A blood test can check for allergy antibodies to alpha-gal. But a positive result alone does not prove you have AGS. Your symptoms and medical history matter, too.

If you are diagnosed, work with your allergist on a plan to avoid triggers, prevent tick bites and treat reactions.

Treat severe symptoms right away. If you suspect anaphylaxis, use prescribed epinephrine immediately and call 911. Seek emergency care even after using epinephrine.

Unexplained allergic reactions deserve answers. Looking at meals, symptom timing and tick exposure together may help uncover a cause that was missed.

Target Audience 
This recording is intended for allergists/immunologists, pulmonologists, primary care clinicians, nurse practitioners, physician assistants, and other healthcare professionals involved in the diagnosis, management, and coordination of care for patients with asthma and allergic conditions. 

Speaker: 

Scott Commins, MD, PhD 

Dr. Commins is the William J. Yount, MD Distinguished Professor at the University of North Carolina at Chapel Hill, where he is a member of the UNC Food Allergy Initiative, the Institute for Global Health and Infectious Diseases, and the Southeastern Center of Excellence for Vector-Borne Diseases. Dr. Commins maintains an active clinical practice and research program related to the alpha-gal mammalian meat allergy syndrome, eosinophilic esophagitis, venom allergy, and the human immune response to tick bites.  

This Advances webinar is in partnership with the American College of Allergy, Asthma & Immunology. ACAAI offers CMEs for physicians for this webinar. If you are an ACAAI member, you can obtain CME through the member portal for this Advances webinar.  

All attendees will be offered a certificate of attendance. No other continuing education credit is provided.  

Sponsored by the American College of Allergy, Asthma and Immunology