From the Guidelines
The Lone Star tick (Amblyomma americanum) is the primary cause of alpha-gal syndrome, an allergy to red meat, as it triggers the body to produce antibodies against alpha-gal, a sugar molecule found in most mammals but not in humans 1.
Key Points
- Alpha-gal syndrome is an IgE-mediated reaction that occurs hours after eating beef, pork, other mammalian meat, or mammalian-derived products 1.
- The allergy is caused by the bite of a tick, with the Lone Star tick being the primary culprit in the United States 1.
- Symptoms of alpha-gal syndrome can range from hives, itching, and gastrointestinal distress to life-threatening anaphylaxis, and typically appear 3-6 hours after meat consumption 1.
- Prevention involves avoiding tick bites through protective clothing, using insect repellents containing DEET or picaridin, performing thorough tick checks after outdoor activities, and promptly removing any attached ticks 1.
- Those who suspect they have developed alpha-gal syndrome should seek medical evaluation from an allergist who can confirm the diagnosis through blood tests and provide guidance on dietary restrictions and emergency treatment options 1.
Management
- A suggested diagnostic and management algorithm for alpha-gal syndrome is provided, which includes avoiding further tick bites, pursuing an alpha-gal avoidance diet, and referring patients with systemic symptoms to an allergy and immunology specialist 1.
- It is also important to counsel patients on the potential for reactions to certain medications and medical products that contain alpha-gal, such as cetuximab 1.
From the Research
Tick-Associated Red Meat Allergy
The tick-associated red meat allergy, also known as Alpha-Gal Syndrome (AGS), is caused by the Lone Star Tick (Amblyomma americanum) [ 2 ].
Key Characteristics of the Allergy
- The allergy is associated with a specific IgE antibody to the oligosaccharide galactose-α-1,3-galactose (alpha-gal) [ 3 ]
- Reactions are delayed 3-6 hours after exposure to red meat [ 3 ]
- Patients may have tolerated red meat for many years prior to the development of allergic reactions [ 3 ]
Identification of the Tick Vector
- The Lone Star Tick (Amblyomma americanum) is identified as the primary tick vector responsible for the red meat allergy [ 2 ]
- Other ticks may also be involved, but the Lone Star Tick is the most commonly associated with this allergy [ 2 ]
Clinical Manifestations and Diagnosis
- The allergy can cause delayed-onset allergic reactions or anaphylaxis due to molecular mimicry [ 4 ]
- Diagnosis is confirmed through challenge testing and avoidance of red meats, foods containing gelatin, and certain medications [ 2 ]