Alpha-gal Syndrome

Alpha-gal syndrome (AGS) is a serious and unusual food allergy to red (mammalian) meat. It occurs in people who have been bitten by certain types of ticks, usually if they’ve been bitten more than once. Ticks are mite-like parasites that feed on blood.

The saliva of some ticks contains a sugar molecule called alpha-gal (α-Gal). When alpha-gal enters the bloodstream, it can increase your sensitivity to red meat. This can trigger an immune system response. Your body reacts as if red meat is harmful, causing allergic symptoms. People with AGS may also react to other products containing alpha-gal, including medications and personal care products.

Currently, there isn’t a cure for AGS. Work with your healthcare provider to find ways to avoid triggers and stay healthy.

What is alpha-gal?

Alpha-gal is a carbohydrate (sugar) molecule found in most mammals. It doesn’t naturally occur in people.

What foods and products contain alpha-gal?

Alpha-gal can be found in:

• Meat, including pork, beef, rabbit, lamb, goat, buffalo or venison.
• Medical products and medications, including the cancer drug cetuximab.
• Products made from mammals, such as gelatin and cow’s milk, as well as personal care and household items.

People with AGS may also react to products with carrageenan. This additive is often used to thicken and preserve food and drinks such as nut milks, meat products and yogurt.

Who gets alpha-gal syndrome?

Alpha-gal syndrome can affect anyone, including those who’ve never previously reacted to red meat. In most cases, it occurs in adults.

People throughout the U.S. have reported this syndrome. You’re more likely to develop AGS if you spend time outdoors in areas where ticks are present.

What types of ticks can cause AGS?

In the U.S., alpha-gal syndrome is most often linked to the lone star tick. It’s the most common human-biting tick in the southeastern states, responsible for more than 90% of all tick bites. It’s also found in the eastern states and parts of the Midwest.

Other species that may cause alpha-gal syndrome include:

• Blacklegged tick in the U.S.
• Cayenne tick in Central America.
• Asian longhorned tick in Asia.

Are there other conditions like alpha-gal syndrome?

Other allergies have symptoms that resemble alpha-gal syndrome, affecting the skin, heart, digestive system and lungs. But symptoms usually develop faster. Getting an accurate diagnosis is important so you can receive appropriate care.

Are there other names for alpha-gal syndrome?

Other names for alpha-gal syndrome are:

• Alpha-gal allergy.
• Mammalian meat allergy.
• Red meat allergy.
• Tick bite meat allergy.

How common is alpha-gal syndrome?

Cases of tick-borne disease doubled from 2004 to 2016, according to the U.S. Centers for Disease Control and Prevention (CDC). The exact number of people diagnosed with AGS is unknown.