How ticks can cause a meat and dairy allergy called alpha-gal syndrome that can kill
Alpha-gal syndrome triggered by tick bites can cause serious allergic reactions after eating meat and dairy – but now there’s a drug for it
It is common knowledge that ticks can spread infections that cause serious illnesses, including Lyme disease. Now health officials are trying to raise awareness of a lesser-known problem: a life-threatening allergy to meat triggered by tick bites.
The problem, known as alpha-gal syndrome, was first linked to a particular species of tick about 15 years ago. But cases are on the rise as more people report symptoms such as hives, diarrhoea and itchiness after eating as little as a mouthful of meat or – in some cases – dairy. The allergy does not affect the consumption of seafood, poultry or eggs.
For years, the standard treatment has involved avoiding foods that come from cows, pigs and lambs while carrying an epinephrine injector in case of medical emergency. But regulators recently approved the first drug for the condition and more therapies may be on the way.
Unlike other tick-borne illnesses, such as Rocky Mountain spotted fever, alpha-gal syndrome is not caused by bacteria or a virus. Instead, it occurs when the human immune system triggers an allergic response to a type of sugar known as alpha-gal.
Alpha-gal is found in the meat of most mammals, but not in humans or other primates. It is also found in the saliva of certain ticks.
When eaten, the sugar is normally harmless. But when ticks bite through the skin, they can introduce the sugar directly into the bloodstream. That triggers the development of antibodies – immune system proteins that fight off foreign invaders – that quickly learn to identify and attack alpha-gal sugar molecules.