Scientists relate the bite of the tick to the allergy to meat: what are its chances of developing it?
More and more people claim to have allergies to any food, and proof of this is the obligation to report the presence of allergens on nutritional labels and restaurant menus. But one thing is what we perceive and the social concern that exists on this issue and a different one is reality. If we stick to the objective data, the prevalence of food allergy is maintained between 1% and 3% of the general population , as in 2004, according to the Alergológica 2015 report, prepared by the Spanish Society of Allergology and Clinical Immunology (chapter 8), which does admit that, in fact, there may be an increase in allergy although it has not been demonstrated.
Fruits (for 44.7% of those allergic to food), nuts (28.4%), shellfish (14.8%), milk (11.2%), fish (10%) and eggs (9.8%) are in the spotlight of many people, who flee from them because a simple bite causes them an attack that usually remains in a skin reaction, itching in the mouth and digestive discomfort (annoying but not serious), although for 12% of those affected who have an anaphylactic reaction they are a vital threat .
Lovers of hamburgers, steak or any cut of beef, beef, pork or lamb breathe easy because, who knows an allergic to meat? Yes, there are and are more and more, especially in the United States, but in other countries, such as Sweden, France, Japan and also in Spain, there are allergic to meat, with the aggravating circumstance that while the reaction to The most common allergenic foods occur within a few minutes of eating them, the symptoms of meat allergy (urticaria, anaphylaxis, angioedema) are delayed for hours, from 3 to 6 , which makes it difficult to relate the burger with itching and rashes.
Therefore, the immunologist Thomas Platts-Mills, of the University of Virginia (USA), and one of the leading researchers on this allergy warned in the Journal of Allergy and Clinical Immunology that doctors have to know that peculiarity of delayed reaction to prevent very serious consequences .
The topic of meat allergy colea in the United States since the 90s without knowing why people who were used to eating meat one day stopped tolerating it . Meanwhile, Platts-Mills investigated in his laboratory the reason why some patients treated with cetuximab – a monoclonal antibody used for advanced colorectal cancer – developed an allergic reaction, and detected that all patients allergic to the drug had IgE antibodies to alpha -gal (a type of sugar linked to meat proteins of non-hominid mammals).
In new research, the immunologist crossed the data of those allergic to cetuximab with those of allergic to meat and found that all belonged to an area of the Rocky Mountains in which people were infected with spotted fever, a disease transmitted by the sting of the tick lone star ( Ammblyoma americanum). Shortly afterwards, Platts-Mills himself and two other members of his team developed an allergy to meat and it was then that, Eureka !, they found a common bond: they had bitten everyone who manifested allergy (to medicine and meat). a tick .
José de La Fuente, research professor of the CSIC of the Health and Biotechnology group of the Research Institute for Hunting Resources, has published several investigations on this matter and confirms that ” the origin of the allergy to red meat is the tick bite , which promotes an immune response that may not always result in the development of anaphylaxis to red meat consumption. ” The explanation for this fact is that “hominids, including humans, evolved losing the ability to produce alpha-gal carbohydrate and the only contact we have with this naturally are intestinal bacteria.”
That is, we are used to the contact with this meat sugar by the digestive route and “the normal response is tolerance”, explains Moisés Labrador, chairman of the immunology committee of the Spanish Society of Allergology and Clinical Immunology (SEAIC). But when he is bitten by a tick “the contact is transdermal with the saliva of this mite” and that is when he may have a delayed anaphylactic reaction (3 to 6 hours after the intake of red meat).
In Spain it is more common in the Cantabrian and the Atlantic areas than in the Mediterranean
The mechanism by which the tick bite modifies the immune response to a type of response that leads to the development of anaphylaxis by consumption of red meat “is not discovered”, says the CSIC researcher, but there is no doubt that a thing is a consequence of the other .
Spain does not get rid of this threat. In fact, “we have reports of individuals who have elevated levels of IgE antibodies to [sugar] alpha-gal that can lead to anaphylaxis due to consumption of red meat.” The risk is real and is not associated with a single species of tick. “, adds De la Fuente. “It is a problem known to allergists and can be diagnosed anywhere in Spain There are cases of delayed anaphylaxis due to meat, especially in Galicia and all the Cantabrian and Atlantic cornices ,” confirms the SEAIC representative. “In the Mediterranean area, it seems to be less frequent.”
In the US, the most problematic are hamburgers on the grill; here, the pig kidneys
The type and manner of preparing the meat also influences the appearance of the symptoms, according to the immunologist. Thus, “in the US it is mainly associated with hamburgers cooked on the grill and in Spain, with pig kidneys.” Although patients may have different sensitivity according to the number of bites, the greater the number of bites, the greater the levels of IgE to alpha. gal and more possibility of allergy with more different meats “.
The message from the specialists is of tranquility, which does not mean that the risk should be underestimated. For the representative of the CSIC it is “an emerging problem, as there are different factors, such as the fact that some species of ticks are spreading in some regions, and also that we have more and more contact with ticks because we are going more to country areas where they live. ” In addition, we must count on that until recently this problem “was not identified and nobody associated that the high levels of antibodies against alpha-gal with an anaphylaxis”.
And given the link found with cetuximab, Labrador notes that “we should ask all patients who are going to be treated with this monoclonal antibody if they have ever been bitten by a tick, and if the answer is affirmative, measure the levels of IgE to alpha-gal. “
If a tick bites you do not try to remove it like a mosquito
Once the danger is identified, the important thing is to protect yourself: go to the field with long pants, check the pets after walking through wild areas and use acaricides. José de la Fuente emphasizes that if we find a tick in a person or an animal,
“you do not have to try to pull it out or tighten it because you can inoculate all the poison it has, it is best to remove them with tweezers, taking them at the junction point. You never have to try to get rid of it like a mosquito. “Here we explain how to treat this bite and the bites of insects and other animals that you will encounter this summer .
So, having had an outbreak of meat allergy implies saying goodbye to the pleasure of eating a hamburger forever? The experts differ . De la Fuente, of the CSIC, considers that it does and argues: “We do not know the mechanism that leads some people to develop allergies and others do not, there are many questions in the air, so it is best to avoid eating red meat.”
Labrador allergist believes that “after a few years the IgE to alpha-gal disappear and that person can return to eat a hamburger, as happened to Platts-Mills.” However, “someone who has had a delayed allergy after eating red meat should consult an allergist to confirm or rule out the diagnosis,” he advises.
For them, there is still the option of eating poultry meat, for which, for now, there is no record of food allergies.