[The alpha-gal syndrome: an allergic reaction to mammalian meat secondary to a tick bite].

Here we present the case of a 68-year-old patient with alpha-gal syndrome. This is a delayed-onset allergic reaction, characteristically occurring 2-6 hours after ingestion of mammalian meat products. The reaction occurs because the patient has developed IgE antibodies to a mammalian oligosaccharide epitope, galactose-α-1,3-galactose (alpha-gal); tick bites induce this IgE antibody response. Presentation varies from chronic urticaria to life-threatening anaphylaxis. The alpha-gal syndrome is usually self-limiting as long as there are no new tick bites. Clinicians should be aware of this syndrome, which is often not recognized as such.