One morning in 2021, I started seeing black spots. I decided that it was probably just because of my iron deficiency, but five minutes later, my vision went entirely black, and I realized that I needed help immediately. When I made it downstairs to my mom's bedroom, I collapsed on the floor and turned bright red from head to toe. After a visit to Urgent Care, it was determined that I was having an anaphylactic reaction. My parents thought I was allergic to the cinnamon in the bagel I had eaten that morning.

Then, almost a year later, I had another reaction. I had not eaten cinnamon. Turns out, I’m basically allergic to everything. Beef, pork, lamb, gelatin, dairy—but not cinnamon. I was diagnosed with alpha-gal syndrome on January 14, 2022. Caused by a bite from a lone star tick, alpha-gal syndrome (AGS) is an allergy to mammalian by-products, but like many others with AGS, I don’t remember getting a tick bite or even seeing a one on me. 

So, how does a tick bite cause an allergy to red meat? According to the CDC, alpha-gal (galactose-α-1,3-galactose) is a type of sugar found in mammals. That same sugar is found in the saliva of lone star ticks. When a tick bites a human, it transfers the alpha-gal sugar into their bloodstream, causing a sensitivity to it. Alpha-gal is found in mammalian meat and other by-products like dairy and gelatin. If someone with AGS eats a food containing alpha-gal, it can trigger an allergic reaction. In some cases, even exposure to fumes from meat or dairy cooking can be enough to cause anaphylaxis, a life threatening reaction. 

Alpha-gal was first observed in the 1990s but wasn’t reported until much later. Compared to other allergies, it’s still relatively new. In 2006, oncologists at the University of Virginia were bewildered by the fact that almost one in four patients had an anaphylactic reaction to a new cancer drug called cetuximab. Thomas Platts-Mills, an allergist at UVA, agreed to help solve the medical mystery. In the southeast in particular, patients experienced more frequent and more severe reactions. 22% of patients in Tennessee and North Carolina had reactions, and anaphylaxis was even more common in patients from Arkansas, Missouri, and Virginia. However, only 1% of patients living in the Northeast had reactions. In the end, Platts-Mills and his team found that most patients with a sensitivity to cetuximab had certain antibodies that attacked the alpha-gal in the drug. 

In 2007, after taking a hike in the Blue Ridge Mountains, Platts-Mills discovered hundreds of ticks feeding on his ankles. A few months later, he had a reaction to two lamb chops while on a trip to Europe, proving that ticks had caused the allergy. 

Alpha-gal syndrome is different from other food allergies in several regards. First is the delayed reaction. With other food allergies, reactions usually happen within minutes. Conversely, those with alpha-gal often experience reactions hours later, and as opposed to being set off by a protein, AGS is triggered by a sugar. 

Another difference between alpha-gal and other allergies is that it often appears suddenly after a lifetime of eating meat without a reaction. Scientists believe that in other allergies, the immune system never tolerates the food in the first place, but with alpha-gal, the tick bite causes an intolerance to a food that was previously tolerated. 

After the intolerance is created, patients can no longer eat red meat, dairy, and other foods containing alpha-gal, but reactions don’t occur after every exposure. Multiple factors contribute to the severity of the reaction, if there is one at all. For example, grilling meat is less likely to cause a reaction than other cooking methods that preserve more fat. 

Alpha-gal is becoming more and more common, especially in the southeastern United States. Up to 3% of the US population has a red meat allergy. Despite the growing number of cases, restaurants and food companies are not required to label if their products contain ingredients that could trigger a reaction. Alpha-gal is far more common than other food allergies, including peanut allergies, which affect around 1.2% of the population. 

The FDA requires packaged foods sold in the US to show if they contain a major food allergen, but alpha-gal isn’t considered one. The only indication that a food is safe for people with AGS is a vegan certification. Even items that don’t contain dairy could be unsafe if they contain gelatin, natural flavors, or sugar that was filtered through bone char. 

And it’s not just food that contains mammalian by-products. Those with alpha-gal often have to stop using their usual cosmetics, which often contain ingredients made from animal products. Even clothing items like wool sweaters or leather shoes could cause a reaction. 

There is no cure for alpha-gal. The only option for those with AGS is to avoid all mammalian by-products. The good news is that if patients aren’t bitten again, the allergy might go away. Giving meat up hasn’t been easy, but even if I get the chance to eat it again, I don’t know if I will. Some days, I wish I could go back to eating beef, but then I remember the terrifying drive to Urgent Care and gladly stick to chicken, turkey, and fish.