Alpha-gal syndrome

Overview

Alpha-gal syndrome is a type of food allergy. It can happen after a tick bite. The allergy is to red meat and other products that come from mammals. Alpha-gal syndrome can be life-threatening.

In the United States, the condition most often begins with the bite of the lone star tick. Other types of ticks cause the condition in different parts of the world, mainly in parts of Europe, Australia, Asia, South Africa, and South and Central America.

Alpha-gal syndrome causes mild to intense allergies to red meat, such as beef, pork or lamb. It also can cause reactions to other foods that come from mammals, such as dairy products or gelatin.

Some people may have alpha-gal syndrome and not know it. There are people who have serious allergic reactions, called anaphylactic reactions, for no known reason. Because the reactions can be delayed for hours, researchers think that some of these people may be affected by alpha-gal syndrome.

The only treatment for alpha-gal syndrome is to not eat red meat or other products from mammals that can trigger reactions. A serious allergic reaction may need medicine called epinephrine and treatment in an emergency room.

Symptoms

An alpha-gal allergic reaction often starts about 2 to 6 hours after you eat something with the alpha-gal molecule.

Symptoms may be mild or lead to serious illness, and include:

• Hives and itching.
• Swelling of the lips, face, throat or eyelids.
• Wheezing or shortness of breath.
• Stomach pain, diarrhea, nausea or vomiting.

Symptoms of alpha-gal syndrome may lessen or go away over time.

When to see a doctor

Get help if you have food allergy symptoms after you eat, even several hours after you eat. See your main healthcare professional or an allergy specialist, called an allergist.

Get emergency medical treatment if you have symptoms of a serious allergic reaction that causes trouble breathing, called anaphylaxis. Symptoms may include:

• Trouble breathing.
• Fast, weak pulse.
• Dizzy or lightheaded feeling.

Causes

Most people with alpha-gal syndrome in the U.S. get the condition from lone star tick bites. Other types of ticks can cause the condition too, mainly in parts of Europe, Australia, Asia, South Africa, and South and Central America.

Experts think the ticks that cause alpha-gal syndrome carry alpha-gal molecules. When a tick that carries these molecules bites a human, the tick sends alpha-gal into the person's body. Experts don't know why some people have strong reactions to alpha-gal.

Risk factors

You're at higher risk if you live or spend time in areas that have ticks that carry alpha-gal. Having more than one tick bite seems to raise the risk even more.

Complications

Alpha-gal syndrome can cause a serious allergic reaction called anaphylaxis. It can be deadly without treatment. A prescription medicine called epinephrine treats anaphylaxis. You can give yourself a shot of epinephrine, also called adrenaline, with a device called an autoinjector (EpiPen, Auvi-Q, others). You also need to go to an emergency room.

Anaphylaxis symptoms can include:

• Tight, narrow airways.
• Swelling of the throat that makes it hard to breathe.
• Fast pulse.
• Feeling dizzy or lightheaded, or passing out.

Healthcare professionals think that some people who get anaphylaxis often and for no clear reason may be living with alpha-gal syndrome that hasn't been diagnosed.

Reactions to medicines and vaccines

Although it's rare, people with antibodies related to alpha-gal syndrome can have allergic reactions to certain medicines and vaccines. These may include the cancer medicine cetuximab (Erbitux). Talk to your healthcare professional before taking a new medicine or getting a vaccine.

Prevention

The best way to prevent alpha-gal syndrome is to prevent tick bites. Stay away from areas where ticks live. Be careful in wooded, bushy areas with long grass. You can lower your risk of getting alpha-gal syndrome by following some simple tips:

• Cover up. When you're in wooded or grassy areas, wear shoes, long pants tucked into your socks, a long-sleeved shirt, a hat and gloves. Try to stay on trails. Don't walk through low bushes and long grass. Keep dogs on leashes.
• Use bug spray. Apply insect repellent with 20% or more of the ingredient DEET to your skin. Adults should apply it to children. Stay away from hands, eyes and mouths. Follow directions carefully. Put products with the ingredient permethrin on clothing or buy pretreated clothing.
• Check yourself, your children and your pets for ticks. Take a good look after you spend time in wooded or grassy areas.
• Shower as soon as you come indoors. Ticks often stay on your skin for hours before they attach themselves. Shower and use a washcloth to try to remove any ticks.
• Remove a tick with tweezers as soon as you can. Gently grasp the tick near its head or mouth. Don't squeeze or crush the tick. Pull out the whole tick with a careful, steady grip. Then get rid of the tick. Clean the area of the bite.