Alphagal Syndrome

The alpha-gal syndrome is a severe allergic reaction caused by a food item containing alpha-gal. It is a rare condition that affects less population of people. Meat from mammals, such as beef, hog, lamb, and venison, can provoke an allergic reaction in people with alpha-gal syndrome. Alpha-gal is a sugar molecule commonly present in most mammals but absent in humans and other primates and it is spread by ticks.

The alpha-gal syndrome presents with itching, hives, stomach cramps, nausea, vomiting, and diarrhea, typically developing several hours after consuming mammal flesh. Anaphylaxis, a potentially fatal reaction, can also happen in some individuals

The alpha-gal syndrome is diagnosed based on the symptoms, clinical presentation, and skin or blood tests. There is no known specific treatment, hence treatment is mainly aimed to treat the symptoms and stay away from mammal flesh.

Alphagal Syndrome: Causes

The causes of alpha-gal syndrome include the following −

  • The Lone Star tick, which is frequently found in the southeast and east of the United States, is known to cause alpha-gal syndrome. Alpha-gal, a sugar molecule commonly present in most mammals but absent in humans and other primates, is the substance that the tick spreads. The immune system detects alpha-gal as an allergen following a tick bite and creates antibodies to combat it.

  • When the individual consumes meat containing alpha-gal the immune system then recognizes the alpha-gal sugar causing the production of histamine and other substances that result in an allergic reaction. Mild to severe symptoms are seen within a few hours after beef consumption.

  • Alpha-gal syndrome is an allergy to the alpha-gal sugar molecule found in mammal meat rather than in meat itself. Alpha-gal syndrome patients can consume fish, fowl, and other non-mammal meats without experiencing any negative side effects. Gelatin, which is made from mammal collagen and other dairy products, can also cause an allergic reaction in people with alpha-gal syndrome.

  • Alpha-gal is recognized by the immune system as an allergen for unknown reasons hence the IgE antibodies are formed against it and these together bind to the mast cells which later released the allergic mediators such as histamine causing the symptoms

Alphagal Syndrome: Symptoms

Alpha gal syndrome presents with the following symptoms −

  • Itching all the body or in some parts, reddish lines or rashes, swelling of the face, lips, and tongue can be seen

  • Gastrointestinal symptoms such as cramps in the stomach, nausea, vomiting, and diarrhea can be present

  • Respiratory symptoms can be present in some patients developing severe allergic reactions presenting with wheezing, chest tightness, and difficulty in breathing.

  • Anaphylaxis is a potentially fatal reaction that results in a rapid heartbeat, low blood pressure, and breathing difficulties in extreme cases.

  • Other signs and symptoms include Headache, fatigue, and general weakness.

Alphagal Syndrome: Risk Factors

The important risk factors of the alpha-gal syndrome include

  • Family history − Individuals who have a personal or family history of allergies or other allergic diseases

  • Smoking − It has been shown that smoking increases the likelihood of getting alpha-gal syndrome may be a result of the immune system-damaging effects of smoke

  • Tick bites − A bite from an infected Lone Star tick is the main risk factor for alpha-gal syndrome. Being outside in places where Lone Star ticks are present increases your risk of getting bitten and developing alpha-gal syndrome. Hikers and hunters may be more likely to get bitten by a Lone Star tick than people who don't work outdoors or in wooded areas. South-eastern and eastern United States, where the Lone Star tick is abundant, are the regions where the alpha-gal syndrome is more commonly seen.

  • Age − More commonly seen in the middle age group and old aged people

Alphagal Syndrome: Diagnosis

The diagnosis of alpha-gal syndrome is based on the history, presentation, and some of the tests which include −

  • Medical history − History of tick bites and any symptoms of an allergic reaction after eating mammal meat is very important to know

  • Physical examination − should be done to look for signs of an allergic reaction, such as rashes, red lines, or swelling

  • Skin test − A skin prick test is done to determine the presence of antibodies to alpha-gal. In this test, a small amount of the allergen-containing alpha-gal is placed on the skin, and a needle is used to gently prick the skin. If a person is allergic to alpha-gal, a raised bump will appear at the site of the prick.

  • Blood test − A blood test helps to measure the levels of alpha-gal antibodies in the blood.

  • Food challenge test − In this test, a person is given a small amount of mammal meat to eat, and the symptoms appear.

Alphagal Syndrome: Treatment

The treatment of alpha-gal syndrome includes −

  • Pharmacological therapy − Antihistamines are used to relieve symptoms such as itching and rashes. In severe cases, adrenaline may be required for use in case of anaphylaxis.

  • Dietary changes − The primary treatment for alpha-gal syndrome is avoiding mammalian meat and products made from it, including beef, pork, lamb, and venison. People with alpha-gal syndrome should also be cautious about consuming processed foods that may contain meat products, such as hot dogs and sausage.

  • Food labeling − People with alpha-gal syndrome should be careful when reading food labels and should always check for any ingredients made from mammal meat or products.

  • Eating out − People with alpha-gal syndrome should be very careful when eating out and ask about the ingredients in the dishes they are ordering.

Alphagal Syndrome: Prevention

Some of the measures to be taken to prevent alpha-gal syndrome include −

  • The main precautionary measure is to avoid tick bites which can be done by wearing protective clothing and using insect repellent when spending time outdoors, especially in wooded areas or areas with tall grass.

  • Cooking the mammalian meat thoroughly can help reduce the risk of alpha-gal syndrome, as the allergen is destroyed by heat

  • Using tick repellent should be done when spending time in tick-infested areas, tick repellent should be used on clothing and exposed skin.

  • Keeping lawns short and removing tall grass, weeds, and leaf litter can help reduce the risk of tick bites.

  • If the individual has a pet in the home, they also carry ticks into the home, so it is important to protect them with tick repellent and to check them regularly for ticks.


The alpha-gal syndrome is the severe reaction to products containing alpha-gal which can become life-threatening if neglected. mainly the mammalian, meat contains alpha-gal. It is transferred from the bite of ticks. It is mainly an allergic reaction that is mediated through IgE antibodies, mast cells, and histamines. People may present mild to severe symptoms, including severe itching, redness, rashes, and anaphylactic reactions.

The diagnosis is mainly based on the history, clinical presentation, and some of the tests such as skin and blood tests. As this condition is life-threatening should be immediately treated with adrenaline if has got a severe reaction. Mild symptoms should be treated with antihistamines. This can be prevented by using tick repellent, which is caused by tick bites, and mainly avoiding meat containing alpha-gal.

Dr. Durgesh Kumar Sinha
Dr. Durgesh Kumar Sinha


Updated on: 02-Mar-2023


Kickstart Your Career

Get certified by completing the course

Get Started