How a Tick Bite Can Cause an Allergy to Red Meat

tick

Lyme disease is currently the most common illness associated with tick bites in the Northern Hemisphere, according to the Centers for Disease Control (CDC). Although a few cases were documented in the 1970s, since the late 1980s residents of the United States have been taught to be wary of ticks and ticks bites in order to prevent contracting this debilitating and sometimes deadly illness. But over the last 10 years, news reports regarding Lyme disease and resultant deaths have diminished considerably, potentially signaling that tick bites are no longer a real threat. However, in 2013 Lyme disease became the 6th most common “Nationally Notifiable disease.”

And while attention has largely been focused on ticks that carry the bacteria which causes Lyme Disease, a new player, the Lone Star tick, has silently emerged. Recently, its bite has been associated with the development of allergic reaction to red meat.

The Lone Star Tick, STARI and Alpha Gal

The Lone Star tick is most commonly found in the eastern, southeastern and south-central United States and has been increasing in numbers. People bitten by the Lone Star tick can develop rashes that appear similar to those that develop in cases of Lyme disease. However, the rash is caused by an unidentified source, not the bacteria that is found in Lyme disease, Borrelia burgdorferi. In fact, saliva from the Lone Start tick actually kills Borrelia burgdorferi. Yet, the similarities between the rash associated with Lyme disease and those resulting from Lone Star tick bites, called southern tick-associated rash illness (STARI), may be one of the reasons the Lone Star tick initially gained notoriety. But it is not the dermatological similarities with Lyme disease that currently has the attention of doctors and scientists across the nation.

The Lone Star tick carries a sugar known as Alpha-Gal, which also occurs in mammalian meat (beef, pork, lamb) but not in humans. When a Lone Star tick bites a person, it transmits the Alpha-Gal through saliva into the human body, which then begins producing IgE antibodies that attack the next time red meat is ingested. Researchers have noted that, in these cases, reaction to red meat is delayed, occurring between 4-8 hours after ingestion. Two things have baffled doctors to this point: usually proteins, not sugars, trigger allergic response, and allergic response is usually immediate rather than delayed several hours. These two differences seem to explain why doctors had previously been unable to explain why people without diagnosed meat allergies were suddenly becoming meat allergic. It wasn’t until 2008 that doctors finally made the correlation between tick bites and subsequent allergic reaction.

Symptoms of Alpha-Gal allergy can range from mild to severe and include itching, hives, swelling, vomiting and anaphylaxis.

Alpha-Gal occurs only in mammalian meat and does not occur in fish or poultry.

Can Other Ticks Be a Problem?

To date, no other ticks have been definitively associated with Alpha-Gal allergies in meat. Researchers continue to investigate other possible sources of Alpha-Gal introduction to humans, but currently a bite from the Lone Star tick is the only known source.

Preventing Tick Bites

Ticks generally are found in heavily wooded areas with lots of tall grass and bushes. You are not likely to encounter ticks in suburban areas, but if you frequent camping areas or hiking trails or engage in other similar outdoor activities, the following prevention tips may help:

  • Use an insecticide that contains DEET on any exposed skin as well as on clothing and gear, or one that contains Permethrin on clothing and gear. Always follow the manufacturer’s instructions when applying an insecticide to yourself or your children.
  • Avoid tall grass, bushes and heavily wooded areas when hiking or camping.
  • Stay in the center of trails if possible.
  • If you or your child does come in contact with ticks, find and remove them as soon as possible.
  • Use a full-length or hand-held mirror to do a full body check upon return from an area known for high tick infestation.
  • Check children carefully, especially in hair and skin creases.
  • Examine all gear and clothing.
  • Examine pets.
  • Place clothing in the dryer and tumble on high heat for at least one hour to kill any remaining ticks that may have been missed.
  • Ticks can ride home on gear or clothing and attach to pets or people later.

Since Alpha-Gal meat allergy is a fairly new food allergy diagnosis, information is unclear whether any treatment protocol other than avoidance is viable. Additionally, the amount of meat necessary to trigger a response varies widely, so reaction is hard to reproduce and often takes time to manifest, up to 8 hours, making investigation difficult.

Some evidence does suggest the allergy may resolve itself over time if further tick bites are avoided. However, as with all allergies, it is important to speak with your child’s doctor to discuss individual implications.


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