It sounds like science fiction.  A hideous blood-sucking alien creeps into the bedroom of an unsuspecting victim while they sleep.  With razor sharp fangs the monster begins to feed, injecting a cocktail of chemicals to keep the blood flowing. As the fiend’s venom works it’s way through the body, a frightening change takes hold.  Forever transformed, the victim is doomed to live in fear of pleasures he once enjoyed.

As bizarre as it sounds, this scary story (with a few embellishments) is not science fiction but true.  Here are the unsettling details.

The blood sucking alien is Amblyomma americanum – the lone star tick.  The tick is found primarily in the Southeastern part of the United States, although some believe that its territory may extend further west.  In some individuals, a bite from the tick triggers the immune system to produce antibodies to a substance found in the saliva of the tick called galactose-α-1,3-galactose or alpha-gal.   Alpha-gal is also found in meats such as beef, lamb, and pork and so once a victim becomes “immunized” by the tick bite, eating a steak, for example, can cause hives or even more severe allergic symptoms.

Unlike most allergic reactions to foods, the alpha-gal reaction can occur 4-6 hours after eating meat.  And although a blood test for the alpha-gal antibody is available, it may not be ordered if the connection between a patients severe allergic reaction and eating a hamburger six hours earlier is not made. To make matters worse, patients who have become sensitized to alpha-gal by a tick bite can also have severe allergic reactions to cetuximab, a new medication used to treat cancer.

So far, the only treatment for alpha-gal sensitivity and the resulting meat allergy is avoidance.