Ticks are arachnids that live in wooded and grassy areas. Ticks attach themselves to a human host as the person brushes past leaves, grass, etc. Ticks do not jump or fall on a person. Once on a host, ticks move to a warm and moist location (eg, armpit, groin, back of the knee, hairline), where they burrow into the host's skin and feed off their blood.

While most ticks are harmless, some carry disease and may transmit illness (eg, Lyme disease, Rocky Mountain spotted fever, Colorado tick fever) to their host. Certain ticks can even inject venom that causes temporary paralysis in their host (called tick paralysis).

Bites from some Amblyomma and Ixodes (and possibly Haemaphysalis) species have been associated with the subsequent development of allergies to mammalian meat (eg, beef, pork) in a small number of patients. It is thought that the allergy is mediated by induced IgE antibodies to alpha-gal (galactose-alpha-1,3-galactose), a mammalian oligosaccharide. Individuals with elevated IgE titers to alpha-gal have experienced urticaria, angioedema, and anaphylaxis symptoms either immediately or 3-6 hours (delayed onset) after ingesting mammalian meat. Exactly how the tick bite leads to development of this allergy is unclear. Implicated tick bites have been noted to itch for 2 or more weeks. A blood test for these IgE antibodies exists.