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Lone Star Tick Bites, Alpha-Gal, and Red Meat Allergies

Linda Crampton is an experienced teacher with a first-class honors degree in biology. She writes about the scientific basis of disease.

The bite of a lone star tick can trigger a red meat allergy in sensitive people.

The bite of a lone star tick can trigger a red meat allergy in sensitive people.

A Strange Cause of a Food Allergy

As strange as it may sound, researchers have discovered that some cases of red meat allergy are caused by a bite from an animal called the lone star tick. The animal normally lives in the southeastern United States but is gradually spreading up the east coast of North America. Its spread to a new area corresponds to an increase in the incidence of meat allergy in that area.

Researchers have noticed that people with major allergy symptoms after lone star tick bites—such as the appearance of large, red welts—are more likely to develop a meat allergy. Blood tests have shown that the affected people are allergic to a sugar in the meat called alpha-gal. The tick bite is believed to sensitize people to the sugar.

Several thousand people in the United States are thought to have developed a red meat allergy due to a bite from a lone star tick. The number of affected people is expected to rise as the tick spreads to other parts of the country on the bodies of animals.

The lone star tick is named from the single light spot on the female's back.

The lone star tick is named from the single light spot on the female's back.

The meat allergy caused by the lone star tick is sometimes referred to as as alpha-gal allergy or alpha-gal syndrome.

Lone Star Tick Facts

Like other ticks, the lone star tick (Amblyomma americanum) isn't an insect. Ticks are relatives of spiders and belong to the same group of animals—the class Arachnida. Insects belong to the class Insecta. The lone star tick belongs to the family Ixodidae or the hard tick family within the class Arachnida.

The species has a brown or red-brown body. It gets its name from the single light spot on the back of the female. This spot may be white, cream, yellow, or gold. Like a spider, the tick has eight legs. It also has appendages called pedipalps around its mouth. Its body is up to a quarter of an inch long. The male is generally smaller than the female. Ticks feed on blood and look larger when they have just had a meal.

A tick's life cycle consists of four stages—the egg, larva, nymph, and adult. The egg hatches into the larva, which looks like a very tiny adult. It has only six legs, however. The larva eventually sheds its outer layer to become a slightly larger nymph, which has eight legs. The nymph finally molts to become the adult.

Since each stage of a tick's life cycle looks almost the same apart from size, its development process is known as incomplete metamorphosis. An animal such as a butterfly undergoes complete metamorphosis because the larva (the caterpillar) looks very different from the adult (the butterfly).

How Do Ticks Find Humans?

Ticks are ectoparasites (ones that live on the outside of a person's body) and can't fly or jump. Nevertheless, they are very good at finding and attaching to people. Some clues that ticks use to detect a suitable host include the heat, moisture, breath, and odours released by a human or animal. Some ticks detect vibrations created by a moving host or the shadow created by the host's body as it moves near the parasite.

Ticks wait on leaves or grass near areas where suitable hosts travel, sensing their environment. Many wait with their front legs outstretched so that they can quickly climb on to a human or an animal as it passes by. This process is known as questing. Others wait in a shelter until they sense that a host is approaching and then run towards it. The lone star tick seems to use both of these strategies. It's described as being "aggressive" in its search for a victim.

A tick grabs hold of a human with the claws at the end of its legs and then searches for an attachment spot. Once it finds a good place, it cuts into the skin with sharp mouthparts. The animal then inserts a feeding tube to withdraw blood. These preparation steps take from minutes to hours. A person may not feel the tick's presence because the animal injects an anesthetic. This prevents the person from feeling pain and trying to dislodge the animal. Once the animal begins feeding, it may continue to do so for hours, days, or even weeks if it isn't removed. The video below shows a nymph attaching to a material.

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What Is Alpha-Gal?

Alpha-gal is the short name for a carbohydrate called galactose-alpha-1,3-galactose. This chemical is found in the muscles (or meat) of all mammals except primates, the order to which humans belong.

Beef, lamb, and pork come from mammals and contain alpha-gal. Meat from mammals is red in colour before being cooked and is therefore known as "red meat". Chickens, turkeys, and other poultry aren't mammals and produce white meat that doesn't contain alpha-gal. Fish don't contain alpha-gal, either.

Alpha-gal is a sugar, or carbohydrate. It's unusual for a sugar to cause a food allergy. Most food allergies are caused by proteins.


How Do the Ticks Cause Red Meat Allergies?

Lone star tick saliva is a complex mixture containing many different chemicals. When a tick bites us, some of its saliva enters our body. The mechanism by which the tick's saliva causes an alpha-gal allergy isn't certain, but the process is thought to be as follows.

When a tick bites an animal, a chemical that either is alpha-gal or closely resembles it enters the tick's gut. When the tick later bites a human, it injects saliva containing alpha-gal into the victim's bloodstream. Up until this point, the person's body may have been able to deal with alpha-gal entering the digestive tract in food. When the alpha-gal enters the blood of a sensitive person via a tick bite, however, the immune system creates antibodies to destroy the irritating chemical. Histamine is also made to help the attack. Unfortunately, the histamine produces the unpleasant symptoms of an allergy.

When a person eats red meat after being sensitized to alpha-gal, their immune system responds as though it has been exposed to the tick chemical again. It creates an even stronger attack against the alpha-gal molecules found in the meat. The overreaction of the immune system produces an allergic response.

Bites From Other Ticks and Meat Allergies

In 2019, researchers from the University of North Carolina found evidence suggesting that although the above scenario may happen, it may not be essential that a tick has recently fed on a mammal's blood in order to cause an allergic reaction to alpha-gal. The research was done in cells placed in lab equipment, not in animals, but it suggests that we may not completely understand the link between lone star tick bites and red meat allergies yet.

Another observation also suggests that we don't have a full explanation for the effect at the moment. People have developed allergies to red meat after a tick bite in Europe, Asia, and Australia. Species other than the loan star tick trigger the allergies in these areas. This leads one to wonder why bites from the lone star tick trigger meat allergies in North America but (apparently) not bites from other ticks.


The proposal that lone star ticks could cause red meat allergies was first suggested in 2007. In North America the link is now generally accepted and is becoming well known. Nevertheless, anyone who suddenly experiences an allergic reaction when they eat red meat shouldn't assume that a tick bite is the cause, even if they know that they've been bitten. It's important to consult a doctor for a diagnosis.

Symptoms of anaphylaxis and anaphylactic shock, which may develop during a severe allergic response

Symptoms of anaphylaxis and anaphylactic shock, which may develop during a severe allergic response

Possible Symptoms of a Red Meat Allergy

The symptoms of an alpha-gal allergy are sometimes severe, which is why the allergy is so worrying. The affected person may experience itching, hives, and swelling. These symptoms may be restricted in range or may be part of anaphylaxis, which is a severe allergic response that affects the whole body. Anaphylaxis may be accompanied by symptoms of anaphylactic shock, which include vomiting, diarrhea, difficulty in breathing, and a rapid and dramatic drop in blood pressure. Anaphylactic shock is a life-threatening condition.

The symptoms of a red meat allergy don't appear immediately after eating the meat but are delayed for several hours. The reason for this isn't known for certain. It's been suggested that the alpha-gal is concentrated in the fatty parts of the meat, which take longer to digest than the protein component. The delay often means that it takes a while to link the allergy symptoms with red meat ingestion (assuming that this is the cause of the condition).

An allergy to red meat due to the presence of alpha-gal may not be permanent. In at least some people it seems to weaken after a few years. This may not be true in every case, however.

Fish and shellfish are a good source of protein for people who can't eat red meat.

Fish and shellfish are a good source of protein for people who can't eat red meat.

Possible Treatment for the Allergy

Anybody with a suspected red meat allergy should consult a doctor. People with a serious allergy are often given an epinephrine auto-injector to carry around with them. A common brand is the EpiPen. Epinephrine is a hormone that counteracts the symptoms of anaphylactic shock, including the low blood pressure and the difficulty in breathing. It also relaxes muscles in the digestive tract.

An alpha-gal sensitive person must avoid red meat (and should always have their epinephrine injector with them if it has been prescribed). Chicken, turkey, eggs, fish, shellfish, beans, and lentils don't contain alpha-gal and are a good source of protein. Vegan "meats", which are really meat substitutes made from plant material, are also available.

In some cases a sensitive person may have to avoid dairy milk, since this also contains alpha-gal. Luckily, a range of non-dairy milks are available today for people who choose not to drink milk or who are allergic to dairy products. Some of these milks are rice, oat, almond, soy, and coconut milks. Alpha-gal is also present in some medical drugs, so it's important that all doctors seen by a patient with an alpha-gal allergy know that the person has the disorder.

Beans are a good source of protein.

Beans are a good source of protein.

Preventing Tick Bites

Red meat allergies can develop due to other causes beside tick bites. Taking steps to avoid bites could be very helpful in preventing an allergy in some people, however. Since the animals can transmit diseases, it's a good idea for everyone to avoid them.

Methods to help prevent the bites are described below. Ticks are small animals and can crawl through small spaces, which needs to be remembered when trying to create a barrier to prevent them from contacting the skin.

  • Avoid woods and bushy areas as well as places known to have a large population of ticks.
  • If you do enter a wooded area, cover your skin as much as possible. Wear long pants tucked into boots or socks. Wear a long sleeved shirt and tuck the shirt into the waistband of pants. Also consider wearing a wide brimmed hat.
  • Stick to established trails instead of making your own. Don't walk through tall grass or other vegetation.
  • Walk near the centre of a trail to avoid overhanging branches or plants where ticks may be waiting for victims.
  • Wear light coloured clothing so that ticks can easily be seen if they get on to your body.
  • Chemical prevention is somewhat controversial, but the standard recommendation for avoiding ticks with a chemical barrier is to apply DEET to exposed skin and permethrin to clothing and shoes.
  • When you get home after a hike, examine your skin carefully for ticks. The sooner the animals are removed from the body, the less likely they are to transmit disease. Pay special attention to hidden areas of the body such as the armpit and the back of the knee, which is where ticks often settle.

Removing Ticks From the Skin

If you do discover a tick attached to your skin, a pair of fine-tipped tweezers is the best tool for removing it. It's a good idea to carry the tweezers in a portable first aid kit while hiking or walking in rural areas. Fine-tipped tweezers should also be available at home, since ticks are sometimes found in gardens. The University of Manitoba video above demonstrates the proper technique for tick removal. Once the animal has been removed, the skin should be disinfected with alcohol and the area monitored.

Tick bites don't necessarily lead to disease. However, pathogens (microbes that cause disease) sometimes pass from the animal’s mouth into the bite site. If unusual or unpleasant symptoms develop at the site of a tick bite or elsewhere in the body soon after the bite, a doctor should be consulted. In addition, if you develop an apparent allergy to red meat (or another food) after previously being able to eat it, a doctor should be consulted for a diagnosis and treatment recommendations.


  • "Allergists say alpha-gal red meat allergy better understood, as numbers continue to increase" from the Vanderbilt University Medical Center
  • Information about ticks from the CDC (Centers for Disease Control and Prevention)
  • "Aggressive tick whose bite makes people allergic to meat is arriving in Canada" from the Canadian Broadcasting Corporation
  • Meat allergies from tick bites are on the rise from NPR (National Public Radio)
  • Probability of red meat allergy from tick bite could be higher than thought from the ScienceDaily news service
  • Alpha-gal syndrome information from the Mayo Clinic
  • Facts about an alpha-gal allergy from the CDC

This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

© 2014 Linda Crampton


Linda Crampton (author) from British Columbia, Canada on September 17, 2014:

It's great that you finally found the cause of your symptoms, Magdalena! It sounds like you've had a very frustrating time. Good luck with your meatless diet.

Magdalena on September 17, 2014:

I was just diagnosed with the Mammalian Meat Allergy and I still can't believe that ticks can cause such allergic reaction... I guess there are worse things that can happen but after four outbreaks of excruciating itchiness and hives, followed by steroids treatments for misdiagnosed illnesses, I'm happy to know what's causing it! Now off to learning how to live without red meat

Linda Crampton (author) from British Columbia, Canada on August 31, 2014:

Hi, lisavanvorst. Thank you for the visit and the comment. Yes, as you say, the connection between the meat and the tick bite is fascinating, but it's also worrying.

Lisa VanVorst from New Jersey on August 31, 2014:

Very interesting and yet scary article. The reaction to this tick bite is so severe. The correlation between the tick bite and red meat is fascinating.

Linda Crampton (author) from British Columbia, Canada on August 30, 2014:

Hi, Audrey. Yes, ticks are abundant in some areas. Unfortunately, red meat allergies seem to be becoming more common. Thanks for the visit.

Audrey Howitt from California on August 30, 2014:

Ticks seem to be all over this time of year in the brush--and they are no laughing matter---I didn't know that there was such a thing as a red meat allergy--

Linda Crampton (author) from British Columbia, Canada on July 26, 2014:

Thank you, MsDora. I appreciate your visit and comment.

Dora Weithers from The Caribbean on July 26, 2014:

Thank you for sharing this very valuable information. So many things which we think are unexplainable just have hidden explanations. I'm sure your article clears up some mystery for red-meat eaters. Good to learn something new.

Linda Crampton (author) from British Columbia, Canada on July 16, 2014:

Hi, Monis Mas. Thanks for the visit and the comment. It must be hard to avoid ticks where you live!

Agnes on July 16, 2014:

Very educational hub. I hate those little creatures, and I try to avoid them, although I live in a very woody area, so it can be difficult.

Linda Crampton (author) from British Columbia, Canada on July 01, 2014:

Hi, Larry. Thank you very much for the great comment! Unfortunately the lone star tick has reached as far west as Oklahoma, but I don't how far it's penetrated into the state.

Larry Rankin from Oklahoma on July 01, 2014:

Extremely informative and expertly researched. I was bitten by a tick several days ago and a red welt appeared. This is a reaction I haven't experienced before. Do you know if these ticks would likely be in Central Oklahoma?

Linda Crampton (author) from British Columbia, Canada on June 29, 2014:

Hi, Cynthia. Yes, although there are other good sources of protein, people who love red meat would probably be very unhappy if they couldn't eat it! Ticks can certainly be a big problem. Thank you very much for the comment.

CMHypno from Other Side of the Sun on June 29, 2014:

Another great hub Alicia and great advice. Tick borne diseases seem to be spreading worldwide and there are more cases of Lyme disease year on year over here in the UK. Not really come across red meat allergy before, but certainly distressing for sufferers who like their steak!

Linda Crampton (author) from British Columbia, Canada on June 26, 2014:

Thanks, Dianna. I appreciate the comment. You're right - it is very important to know about ticks during the summer months!

Dianna Mendez on June 26, 2014:

This is really good information to have, especially with the hot summer months upon us. I didn't know they inject an anesthetic into your skin. No wonder people can't detect them earlier. Great read and very interesting.

Linda Crampton (author) from British Columbia, Canada on June 25, 2014:

Thanks for the visit, Deb. Hopefully you'll never develop a milk allergy!

Deb Hirt from Stillwater, OK on June 25, 2014:

This was something that I didn't know about, but since it is very rare that I eat meat, it could be a moot point. However, I do drink milk...

Linda Crampton (author) from British Columbia, Canada on June 25, 2014:

Hi, Nell. I expect you're right. Some people may never discover that their red meat allergy is due to a tick bite! Thank you very much for the visit and the comment.

Nell Rose from England on June 25, 2014:

Hi Alicia, I never knew that! imagine being allergic to red meat because of the chemical from the tick! I wonder how many doctors actually diagnose it right when someone goes to them? not many I would imagine! I learned something new, so thanks, nell

Linda Crampton (author) from British Columbia, Canada on June 19, 2014:

Thank you very much for the comment, Peggy, as well as the pin, tweet and share! I suspect that most people think of Lyme disease when they think of a disease transmitted by ticks. If lone star ticks continue to spread, though, we may be hearing more about red meat allergies caused by tick bites.

Peggy Woods from Houston, Texas on June 19, 2014:

I had no idea that ticks could cause red meat allergies. Lyme Disease is the first thing that I think of with regard to adverse effects from tick bites. Very informative post. It is good to know of these potential dangers and take precautions rather than suffer the consequences. Will share this by pinning, tweeting and sharing.

Linda Crampton (author) from British Columbia, Canada on June 19, 2014:

I'm glad that your wife had tweezers with her when you met the ticks, Mel! Tweezers can be very useful for removing ticks from the skin. Thanks for the visit and the comment.

Mel Carriere from Snowbound and down in Northern Colorado on June 19, 2014:

I am fortunate to live in the West, where I have never had a problem with ticks. One time after exploring a grassy civil war battlefield in northern Georgia I found two ticks in my abdomen and I was absolutely horrified. Luckily the wife was there to do surgery with the tweezers. I don't think they were the ticks you described because they were black. I have also never suffered from red meat allergies. I could eat an entire side of beef for dinner with no ill effects. Great hub!

Linda Crampton (author) from British Columbia, Canada on June 17, 2014:

Thank you very much, Vicki! I appreciate your kind comment. I'm very glad that we don't have lone star ticks here, too!

Vickiw on June 17, 2014:

Great Hub Alicia! Glad we don't have them on the west coast of BC. Your information is very comprehensive, as all your Hubs are!

Linda Crampton (author) from British Columbia, Canada on June 17, 2014:

Hi, Liz. Lyme disease is definitely something that I would like to avoid! I'm glad your dog recovered from this illness. Thanks for the visit and the comment.

Elizabeth Parker from Las Vegas, NV on June 17, 2014:

Oh, I hate ticks. When I lived in NY, I remember there were so many of them. Here in Vegas, we don't really have them, however, my dog (foster dog at the time) had gotten lyme disease. Thankfully, we found it in time. Thanks for posting!

Linda Crampton (author) from British Columbia, Canada on June 17, 2014: