A new study by Susan Wolver, MD, and Diane Sun, MD, from Virginia Commonwealth University, and colleagues, discovered that the tick bite is the cause for a delayed allergic reaction to red meat. Their research, published by Springer in the Journal of General Internal Medicine, explains why people bitten by a tick may become allergic to red meat.
Delayed anaphylaxis – a severe, life-threatening allergic reaction to meat – is a new syndrome that was initially identified in the southeastern United States.
Ticks are tiny spider-like bugs. When they bite, they latch onto skin and feed on blood. Tick bites occur most often during early spring and late summer months. Simple ways to prevent tick bites include avoiding bushy and wooded areas with high grass, walking in the center of trails, and applying insect repellent. It is recommended to shower as soon as returning inside after exploring or working outdoors and also to perform a full body inspection for any ticks.
The researchers state that any time around three to six hours after eating red meat for dinner, patients may wake up in the middle of the night with hives or anaphylaxis. The link between anaphylaxis and eating red meat had remained indefinable until recent research.
The examination of three patient case studies, by Sun, Wolver, and colleagues, revealed insight on this reaction. Antibodies to a carbohydrate (alpha-gal) that are produced in a patient’s blood after a tick bite, specifically the Lone Star tick, is believed to be the cause of the allergy. Lone Star ticks are aggressive females that can be identified by the white spot, or star, on the center of their back and are known to go long distances in search of their host.
The alpha-gel is also found in meat. After a person is bitten by a tick and eats meat, his or her immune system triggers the release of histamine in response to the presence of this carbohydrate substance. The person may then develop hives and anaphylaxis.
Meat-induced anaphylaxis is the first food-induced severe allergic reaction due to a carbohydrate rather than a protein. Usually, anaphylaxis occurs immediately after exposure; but in this case, the reaction is delayed.
The experts concluded:
“Where ticks are endemic, for example in the southeastern United States, clinicians should be aware of this new syndrome when presented with a case of anaphylaxis. Current guidance is to counsel patients to avoid all mammalian meat- beef, pork, lamb, and venison.”
Written by Sarah Glynn