Ticks and Alpha-gal Syndrome

I remember finding what I thought was a dog tick on my belly and thinking, “Oh good! It is not a deer tick! I don’t have to worry about Lyme with this one!” HA! Five weeks later, I woke in a full body rash. Four additional weeks later, I was diagnosed with Alpha Gal. Life has been on an unchartered course ever since. However, I remain hopeful and positive!

—Charlotte Meyer

Which Tick Species Can Cause Alpha-gal Syndrome?

Ticks associated with, or in some cases suspected of being associated with, the onset of alpha-gal syndrome include:

  • In the U.S., the Lone Star Tick (Amblyomma americanum) (1)
  • In Europe, the Castor Bean Tick (Ixodes ricinus)(2), Rhipicephalus bursa (3), and Hyalomma marginatum (3)
  • In Australia, the Australian Paralysis Tick (Ixodes holocyclus) (4) and (Ixodes endopalpiger australiensis) (5)
  • In Central America, Ixodes cajennense(6)
  • In Japan and Korea, possibly Ixodes nipponensis? (7)
  • Also in Japan, Haemaphysalis longicornis (8) and Amblyomma testudinarium (9)
  • In Brazil, possibly Amblyomma sculptum? (7)
  • In the Ivory Coast, possibly Amblyomma variegatum? (7)
  • In South Africa, the vector of sensitization has not yet been identified.

What We Don’t Know About Ticks and AGS

  • We don’t know which other species of ticks can cause alpha-gal syndrome, although it’s likely that others do.
  • We don’t know if Black-legged Ticks (Ixodes scapularis) can cause alpha-gal syndrome. They may, as they have alpha-gal in their saliva and are closely related to other species that do. (10)
  • We don’t know if chiggers can cause AGS. There is speculation that they might. (11)
  • We don’t know if other ectoparasites or endoparasites can trigger AGS, although it’s thought that they may. ()

How Do Ticks Cause AGS?

  • Ticks eject saliva into the bite sites they create in the skin.
  • The saliva triggers an immune response that leads to alpha-gal syndrome.
  • The mechanism by which this occurs is still being studied, but it’s believed that AGS is triggered by alpha-gal in ticks’ saliva, possibly in conjunction with adjuvants.

How Long Does a Tick Have to Feed to Trigger AGS?

  • It can take many hours for ticks to transmit some diseases, but they can trigger AGS as soon as they bite you and eject their saliva into your skin.
  • For this reason, it is best to avoid tick bites in the first place, not just remove ticks promptly after they bite you, although you should do that, too.

I was at a party and felt something crawling on my leg inside my jeans. I pulled down my jeans and looked for the critter. My gf got poed and interrupted my search. Got home a few hours later and she found the Lonestar tick attached on my hip. Looking for a new gf.

—Claiborne Taylor

Do All People Who Are Bitten by Ticks That Can Trigger AGS Get It?

  • No, most people who are bitten by ticks that can trigger AGS do not develop AGS.

What Other Illnesses Can I Get from Ticks?

If you are bitten by a tick, you might not just develop AGS. You might also acquire a tick-borne disease.

  • Ticks transmit many diseases.
  • Different tick species transmit different diseases.
  • If you get AGS after a tick bite, don’t assume that all the symptoms you experience afterwards are caused by it.
  • Talk to your doctor about ruling out tick-borne diseases and other illnesses which could be contributing to your symptoms.
  • Learn more about North American tick-borne diseases and the species that transmit them from the CDC.

References–in development

1. Commins, S. P., et al. (2011). “The relevance of tick bites to the production of IgE antibodies to the mammalian oligosaccharide galactose-α-1,3-galactose.” Journal of Allergy and Clinical Immunology 127(5): 1286-1293.e1286.
2. Hamsten, C., et al. (2013). “Identification of galactose-alpha-1,3-galactose in the gastrointestinal tract of the tick Ixodes ricinus; possible relationship with red meat allergy.” Allergy 68(4): 549-552.
3.Mateos-Hernandez, L., et al. (2017). “Tick-host conflict: immunoglobulin E antibodies to tick proteins in patients with anaphylaxis to tick bite.” Oncotarget 8(13): 20630-20644.
4. Van Nunen, S. (2007). “THE ASSOCIATION BETWEEN IXODES HOLOCYCLUS TICK BITE REACTIONS AND RED MEAT ALLERGY” ASCIA 2007 ALLERGIC DISEASE POSTERS.” Internal Medicine Journal 37(s5): A128-A135.
5. Kwak, M., et al. (2018). “A novel Australian tick Ixodes (Endopalpiger) australiensis inducing mammalian meat allergy after tick bite.” Asia Pac Allergy 8(3): e31.
6. Wickner, P. G. and S. P. Commins (2014). “The First 4 Central American Cases Of Delayed Meat Allergy With Galactose-Alpha-1,3-Galactose Positivity Clustered Among Field Biologists In Panama.” Journal of Allergy and Clinical Immunology 133(2, Suppl. S): AB212.
7. van Nunen, S. A. (2018). “Tick-induced allergies: mammalian meat allergy and tick anaphylaxis.” Med J Aust 208(7): 316-321.
8.Chinuki, Y., et al. (2016). “Haemaphysalis longicornis tick bites are a possible cause of red meat allergy in Japan.” Allergy 71(3): 421-425.
9. Hashizume, H., et al. (2018). “Repeated Amblyomma testudinarium tick bites are associated with increased galactose-α-1,3-galactose carbohydrate IgE antibody levels: a retrospective cohort study in a single institution.” J Am Acad Dermatol 78(6): 1135-1141.e1133.
10. Crispell, G., et al. (2019). “Discovery of Alpha-Gal-Containing Antigens in North American Tick Species Believed to Induce Red Meat Allergy.” Front Immunol 10: 1056.
11. Stoltz, L. P., et al. (2019). “Could chiggers be contributing to the prevalence of galactose-alpha-1,3-galactose sensitization and mammalian meat allergy?” J Allergy Clin Immunol Pract 7(2): 664-666.