What to know about alpha-gal syndrome, the life-threatening meat allergy caused by tick bites
By AP and William Muthama, June 14, 2026Ticks are widely known for spreading infections that can cause serious illnesses, including Lyme disease. But health officials are also highlighting a lesser-known condition linked to tick bites: a potentially life-threatening allergy to meat.
Known as alpha-gal syndrome, the condition was first linked to a particular tick species about 15 years ago. It occurs when the body’s immune system reacts to a sugar found in most mammals.
People with the allergy can develop symptoms such as hives, itching and diarrhoea, sometimes several hours after eating meat. In some cases, reactions can be severe.
The condition does not affect poultry or seafood. People with alpha-gal syndrome can generally eat chicken, turkey, eggs and fish.
For years, treatment has mainly involved avoiding foods made from mammals, including beef, pork and lamb, and carrying an epinephrine injector in case of a severe allergic reaction. A drug approved by US regulators has also provided another option for reducing the risk of serious reactions.
What causes alpha-gal syndrome?
Unlike some tick-borne diseases, alpha-gal syndrome is not caused by a bacterium or virus. It is an allergic reaction to a sugar known as alpha-gal.
The sugar is found naturally in most mammals but is not found in humans or other primates. It is also present in the saliva of some ticks.
When a tick carrying alpha-gal bites a person, the sugar can enter the body through the skin. The immune system may then produce antibodies against it.
Once this immune response develops, eating meat or other products containing alpha-gal can trigger an allergic reaction.
Scott Commins, an alpha-gal syndrome researcher at the University of North Carolina, said the way the substance enters the body through the skin may help explain why an allergic response develops.
The reaction does not necessarily happen immediately. Some people experience symptoms several hours after eating meat or dairy products, while the allergy itself may take weeks or months to develop after a tick bite.
Why are more cases being diagnosed?
Researchers say the increase in diagnosed cases may partly be due to greater awareness among doctors and the public.
Maria Diuk-Wasser, a Columbia University researcher who studies tick-borne diseases, said more people are now aware of the condition and know what symptoms to look for.
The spread of ticks into new areas may also be contributing to the increase.
The lone star tick, which is considered the main source of alpha-gal syndrome in the United States, is commonly found in the eastern and southern parts of the country. However, it has increasingly been reported in areas farther north, including parts of the Great Lakes region and Martha’s Vineyard in Massachusetts.
Researchers are also studying whether other tick species could transmit the condition.
A 2023 study by the US Centres for Disease Control and Prevention estimated that about 450,000 Americans had developed alpha-gal syndrome.
What are the symptoms?
People with alpha-gal syndrome can experience a range of symptoms.
These may include hives, itching, dizziness, difficulty breathing and swelling of the lips, tongue, throat or eyelids. Some people experience mainly digestive symptoms, such as stomach pain, nausea, vomiting and diarrhoea.
Anyone experiencing difficulty breathing or swelling of the throat after eating should seek emergency medical attention.
Doctors generally diagnose the condition using a combination of symptoms, a patient’s medical history and a blood test that looks for antibodies against alpha-gal.
However, a positive blood test does not necessarily mean that a person has the syndrome.
Scott Commins noted that some people can test positive for alpha-gal antibodies without developing symptoms, meaning the test needs to be considered alongside the patient’s actual symptoms and history.
Which foods should people avoid?
People diagnosed with alpha-gal syndrome are generally advised to avoid meat from mammals, including beef, pork and lamb.
Some people may still be able to consume dairy products such as milk, cheese and butter, although this varies from person to person.
Those with more severe reactions may also need to avoid products containing mammalian ingredients such as gelatin, which can be found in foods including some marshmallows and gummy sweets.
The condition can also have implications beyond food. Some medical products and implants contain materials derived from cows or pigs, including certain types of heart valves.
For some people, the allergy may eventually become less severe or disappear. Commins has observed this in around 15% to 20% of his patients. However, avoiding further tick bites remains important.
What treatments are available?
There is currently no treatment that removes alpha-gal syndrome altogether. Avoiding exposure to foods and products that trigger reactions remains an important part of managing the condition.
In 2024, the US Food and Drug Administration approved Xolair, an injectable medicine, for the treatment of certain food allergies. The drug can help reduce the risk of severe allergic reactions following accidental exposure, although it does not cure the underlying allergy.
Xolair works by targeting a part of the immune system involved in allergic reactions. The medicine had previously been used for conditions including asthma.
Researchers are continuing to study alpha-gal syndrome and are looking at whether other existing medicines could provide additional treatment options.
For now, understanding the condition, recognising its symptoms and preventing further tick bites remain important for people who develop this unusual allergy.