Understanding Alpha-Gal Syndrome: Causes, Symptoms, and Prevention

Although often overlooked, alpha-gal syndrome (AGS) can cause severe and potentially life-threatening allergic reactions. In 2024, a 47-year-old pilot from New Jersey died from anaphylaxis linked to AGS after experiencing a delayed allergic reaction several hours after eating a hamburger.

What is Alpha-Gal Syndrome?

Alpha-gal syndrome (AGS) is an emerging tick bite-associated allergy that may affect up to 450,000 people in the United States, according to CDC estimates. The number of diagnosed cases has increased substantially in recent years, although the true number of affected individuals may be even higher due to underdiagnosis and lack of awareness. Both children and adults can develop the condition.

AGS occurs when the immune system reacts to galactose-alpha-1,3-galactose (alpha-gal), a sugar molecule found in most mammals, including cows, pigs, lambs, and goats. After becoming sensitized, some individuals may develop allergic reactions after consuming meat or other mammalian-derived products.

Unlike many food allergies that cause immediate symptoms, AGS reactions are typically delayed and often occur several hours after eating.

Causes of Alpha-Gal Syndrome

AGS most commonly develops after bites from certain tick species, especially the Lone Star tick in the United States. Tick bites may sensitize the immune system to alpha-gal, leading to allergic reactions after consuming mammalian meat or related products.

Symptoms of Alpha-Gal Syndrome

Symptoms of AGS usually appear 2–6 hours after consuming meat or other mammalian products. Reactions can range from mild discomfort to life-threatening emergencies.

Common symptoms include:

• Hives or skin rash

• Swelling of the lips, tongue, throat, or eyelids

• Coughing or difficulty breathing

• Wheezing

• Indigestion or heartburn

• Nausea or vomiting

• Abdominal pain or diarrhea

• Dizziness or decreased blood pressure

In severe cases, AGS may cause anaphylaxis, a potentially life-threatening allergic reaction that requires immediate medical attention.

Diagnosis of Alpha-Gal Syndrome

Diagnosis may include blood testing for alpha-gal-specific IgE antibodies, although results must be interpreted alongside symptoms and clinical history since some individuals test positive without experiencing reactions.

Unlike most food allergies, AGS reactions are often delayed by several hours, making the condition more difficult to recognize and diagnose.

Treatment and Lifestyle Adjustments

There is currently no cure for AGS. Treatment focuses on avoiding trigger foods and managing allergic reactions.

Many individuals with AGS need to avoid meat from mammals, including:

• Beef

• Pork

• Lamb

• Venison

  
  

Some people may also react to dairy products, gelatin, or other mammalian-derived ingredients.

Certain medications and medical products derived from mammals may also trigger reactions in sensitive individuals, including cetuximab (Erbitux) and some animal-derived medical products.

Mild reactions are often treated with antihistamines. Individuals at risk for severe reactions are typically prescribed an epinephrine auto-injector for emergency use.

Preventing Alpha-Gal Syndrome

Preventing tick bites is currently the best way to reduce the risk of developing AGS.

Helpful prevention strategies include:

• Avoiding grassy, brushy, and wooded areas where ticks are common whenever possible

• Walking in the center of trails

• Using EPA-registered insect repellents

• Wearing long sleeves and long pants outdoors

• Treating clothing and gear with permethrin

• Checking skin, clothing, and pets carefully after spending time outdoors

If a tick is found attached to the skin, it should be removed promptly using fine-tipped tweezers. Grasp the tick as close to the skin as possible and pull upward with steady, even pressure.

Conclusion

Greater awareness among both healthcare professionals and the public may help reduce delayed or missed diagnoses. Recognizing symptoms early, avoiding trigger foods, and preventing future tick bites are important steps in managing this condition.

Individuals who suspect they may have AGS should consult a qualified healthcare professional for proper evaluation and personalized medical advice.

References:

• Mollah F, Zacharek MA, Benjamin MR. What Is Alpha-Gal Syndrome? JAMA. Published online December 08, 2023. doi:10.1001/jama.2023.23097.

• https://www.cdc.gov/alpha-gal-syndrome/about/index.html, Accessed May 31, 2024